Unterschiede

Hier werden die Unterschiede zwischen zwei Versionen angezeigt.

--- lpic:bash [2009/02/12 16:15] – gelöscht d.weller
+++ lpic:bash [2009/02/12 16:29] (aktuell) – angelegt d.weller
@@ Zeile 1: / Zeile 1: @@
+bash(1)                                                                bash(1)
+NAME
+       bash - GNU Bourne-Again SHell
+SYNOPSIS
+       bash [options] [file]
+COPYRIGHT
+       Bash is Copyright (C) 1989-2005 by the Free Software Foundation, Inc.
+DESCRIPTION
+       Bash  is  an  sh-compatible  command language interpreter that executes
+       commands read from the standard input or from a file.  Bash also incor-
+       porates useful features from the Korn and C shells (ksh and csh).
+       Bash  is  intended  to  be a conformant implementation of the Shell and
+       Utilities portion  of  the  IEEE  POSIX  specification  (IEEE  Standard
+.1).  Bash can be configured to be POSIX-conformant by default.
+OPTIONS
+       In  addition  to  the  single-character shell options documented in the
+       description of the set builtin command, bash interprets  the  following
+       options when it is invoked:
+       -c string If  the  -c  option  is  present, then commands are read from
+                 string.  If there are arguments after the  string,  they  are
+                 assigned to the positional parameters, starting with $0.
+       -i        If the -i option is present, the shell is interactive.
+       -l        Make bash act as if it had been invoked as a login shell (see
+                 INVOCATION below).
+       -r        If the -r option is present,  the  shell  becomes  restricted
+                 (see RESTRICTED SHELL below).
+       -s        If  the -s option is present, or if no arguments remain after
+                 option processing, then commands are read from  the  standard
+                 input.   This  option  allows the positional parameters to be
+                 set when invoking an interactive shell.
+       -D        A list of all double-quoted strings preceded by $ is  printed
+                 on  the standard output.  These are the strings that are sub-
+                 ject to language translation when the current locale is not C
+                 or  POSIX.   This  implies the -n option; no commands will be
+                 executed.
+       [-+]O [shopt_option]
+                 shopt_option is one of the  shell  options  accepted  by  the
+                 shopt   builtin  (see  SHELL  BUILTIN  COMMANDS  below).   If
+                 shopt_option is present, -O sets the value of that option; +O
+                 unsets  it.   If  shopt_option is not supplied, the names and
+                 values of the shell options accepted by shopt are printed  on
+                 the  standard  output.   If  the invocation option is +O, the
+                 output is displayed in a format that may be reused as  input.
+       --        A  --  signals the end of options and disables further option
+                 processing.  Any arguments after the -- are treated as  file-
+                 names and arguments.  An argument of - is equivalent to --.
+       Bash  also  interprets  a  number  of  multi-character  options.  These
+       options must appear on the command  line  before  the  single-character
+       options to be recognized.
+       --debugger
+              Arrange for the debugger profile to be executed before the shell
+              starts.  Turns on extended debugging mode (see  the  description
+              of  the  extdebug  option  to the shopt builtin below) and shell
+              function tracing (see the description of the -o functrace option
+              to the set builtin below).
+       --dump-po-strings
+              Equivalent  to -D, but the output is in the GNU gettext po (por-
+              table object) file format.
+       --dump-strings
+              Equivalent to -D.
+       --help Display a usage message on standard  output  and  exit  success-
+              fully.
+       --init-file file
+       --rcfile file
+              Execute commands from file instead of the standard personal ini-
+              tialization file ~/.bashrc if  the  shell  is  interactive  (see
+              INVOCATION below).
+       --login
+              Equivalent to -l.
+       --noediting
+              Do  not  use the GNU readline library to read command lines when
+              the shell is interactive.
+       --noprofile
+              Do not read either the system-wide startup file /etc/profile  or
+              any   of  the  personal  initialization  files  ~/.bash_profile,
+              ~/.bash_login, or ~/.profile.   By  default,  bash  reads  these
+              files  when  it  is  invoked  as  a  login shell (see INVOCATION
+              below).
+       --norc Do  not  read  and  execute  the  personal  initialization  file
+              ~/.bashrc  if  the  shell  is interactive.  This option is on by
+              default if the shell is invoked as sh.
+       --posix
+              Change the behavior of bash where the default operation  differs
+              from the POSIX standard to match the standard (posix mode).
+       --restricted
+              The shell becomes restricted (see RESTRICTED SHELL below).
+       --verbose
+              Equivalent to  -v.
+       --version
+              Show  version information for this instance of bash on the stan-
+              dard output and exit successfully.
+ARGUMENTS
+       If arguments remain after option processing, and neither the -c nor the
+       -s  option  has  been supplied, the first argument is assumed to be the
+       name of a file containing shell commands.  If bash is invoked  in  this
+       fashion,  $0 is set to the name of the file, and the positional parame-
+       ters are set to the remaining arguments.  Bash reads and executes  com-
+       mands  from this file, then exits.  Bash's exit status is the exit sta-
+       tus of the last command executed in the script.   If  no  commands  are
+       executed,  the  exit status is 0.  An attempt is first made to open the
+       file in the current directory, and, if no file is found, then the shell
+       searches the directories in PATH for the script.
+INVOCATION
+       A  login shell is one whose first character of argument zero is a -, or
+       one started with the --login option.
+       An interactive shell is one started without  non-option  arguments  and
+       without the -c option whose standard input and error are both connected
+       to terminals (as determined by isatty(3)), or one started with  the  -i
+       option.   PS1 is set and $- includes i if bash is interactive, allowing
+       a shell script or a startup file to test this state.
+       The following paragraphs describe how bash executes its startup  files.
+       If  any  of  the files exist but cannot be read, bash reports an error.
+       Tildes are expanded in file names as described below under Tilde Expan-
+       sion in the EXPANSION section.
+       When  bash is invoked as an interactive login shell, or as a non-inter-
+       active shell with the --login option, it first reads and executes  com-
+       mands  from  the file /etc/profile, if that file exists.  After reading
+       that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile,
+       in  that order, and reads and executes commands from the first one that
+       exists and is readable.  The --noprofile option may be  used  when  the
+       shell is started to inhibit this behavior.
+       When  a  login  shell  exits, bash reads and executes commands from the
+       file ~/.bash_logout, if it exists.
+       When an interactive shell that is not a login shell  is  started,  bash
+       reads  and executes commands from ~/.bashrc, if that file exists.  This
+       may be inhibited by using the --norc option.  The --rcfile file  option
+       will  force  bash  to  read  and  execute commands from file instead of
+       ~/.bashrc.
+       When bash is started non-interactively, to  run  a  shell  script,  for
+       example, it looks for the variable BASH_ENV in the environment, expands
+       its value if it appears there, and uses the expanded value as the  name
+       of  a  file to read and execute.  Bash behaves as if the following com-
+       mand were executed:
+              if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
+       but the value of the PATH variable is not used to search for  the  file
+       name.
+       If  bash  is  invoked  with  the name sh, it tries to mimic the startup
+       behavior of historical versions of sh as  closely  as  possible,  while
+       conforming  to the POSIX standard as well.  When invoked as an interac-
+       tive login shell, or a non-interactive shell with the  --login  option,
+       it  first  attempts  to read and execute commands from /etc/profile and
+       ~/.profile, in that order.  The  --noprofile  option  may  be  used  to
+       inhibit  this  behavior.  When invoked as an interactive shell with the
+       name sh, bash looks for the variable ENV, expands its value  if  it  is
+       defined,  and uses the expanded value as the name of a file to read and
+       execute.  Since a shell invoked as sh does not attempt to read and exe-
+       cute  commands from any other startup files, the --rcfile option has no
+       effect.  A non-interactive shell invoked with  the  name  sh  does  not
+       attempt  to  read  any  other  startup files.  When invoked as sh, bash
+       enters posix mode after the startup files are read.
+       When bash is started in posix mode, as with the  --posix  command  line
+       option, it follows the POSIX standard for startup files.  In this mode,
+       interactive shells expand the ENV variable and commands  are  read  and
+       executed  from  the  file  whose  name is the expanded value.  No other
+       startup files are read.
+       Bash attempts to determine when it is being run  by  the  remote  shell
+       daemon,  usually  rshd.  If bash determines it is being run by rshd, it
+       reads and executes commands from ~/.bashrc, if that file exists and  is
+       readable.  It will not do this if invoked as sh.  The --norc option may
+       be used to inhibit this behavior, and the --rcfile option may  be  used
+       to  force  another  file to be read, but rshd does not generally invoke
+       the shell with those options or allow them to be specified.
+       If the shell is started with the effective user (group) id not equal to
+       the real user (group) id, and the -p option is not supplied, no startup
+       files are read, shell functions are not inherited from the environment,
+       the  SHELLOPTS  variable, if it appears in the environment, is ignored,
+       and the effective user id is set to the real user id.  If the -p option
+       is  supplied  at  invocation, the startup behavior is the same, but the
+       effective user id is not reset.
+DEFINITIONS
+       The following definitions are used throughout the rest  of  this  docu-
+       ment.
+       blank  A space or tab.
+       word   A  sequence  of  characters  considered  as a single unit by the
+              shell.  Also known as a token.
+       name   A word consisting only of  alphanumeric  characters  and  under-
+              scores,  and beginning with an alphabetic character or an under-
+              score.  Also referred to as an identifier.
+       metacharacter
+              A character that, when unquoted, separates words.   One  of  the
+              following:
+              |  & ; ( ) < > space tab
+       control operator
+              A token that performs a control function.  It is one of the fol-
+              lowing symbols:
+              || & && ; ;; ( ) | <newline>
+RESERVED WORDS
+       Reserved words are words that have a special meaning to the shell.  The
+       following words are recognized as reserved when unquoted and either the
+       first word of a simple command (see SHELL GRAMMAR below) or  the  third
+       word of a case or for command:
+       !  case  do done elif else esac fi for function if in select then until
+       while { } time [[ ]]
+SHELL GRAMMAR
+   Simple Commands
+       A simple command is a sequence of optional  variable  assignments  fol-
+       lowed  by  blank-separated  words and redirections, and terminated by a
+       control operator.  The first word specifies the command to be executed,
+       and  is  passed  as  argument  zero.  The remaining words are passed as
+       arguments to the invoked command.
+       The return value of a simple command is its exit status,  or  128+n  if
+       the command is terminated by signal n.
+   Pipelines
+       A pipeline is a sequence of one or more commands separated by the char-
+       acter |.  The format for a pipeline is:
+              [time [-p]] [ ! ] command [ | command2 ... ]
+       The standard output of command is connected via a pipe to the  standard
+       input  of  command2.   This connection is performed before any redirec-
+       tions specified by the command (see REDIRECTION below).
+       The return status of a pipeline is the exit status of the last command,
+       unless  the  pipefail  option  is enabled.  If pipefail is enabled, the
+       pipeline's return status is the value of the last  (rightmost)  command
+       to  exit  with a non-zero status, or zero if all commands exit success-
+       fully.  If the reserved word !  precedes a pipeline, the exit status of
+       that  pipeline  is the logical negation of the exit status as described
+       above.  The shell waits for all commands in the pipeline  to  terminate
+       before returning a value.
+       If  the  time reserved word precedes a pipeline, the elapsed as well as
+       user and system time consumed by its execution are  reported  when  the
+       pipeline  terminates.   The -p option changes the output format to that
+       specified by POSIX.  The TIMEFORMAT variable may be  set  to  a  format
+       string  that  specifies how the timing information should be displayed;
+       see the description of TIMEFORMAT under Shell Variables below.
+       Each command in a pipeline is executed as a separate process (i.e.,  in
+       a subshell).
+   Lists
+       A  list  is a sequence of one or more pipelines separated by one of the
+       operators ;, &, &&, or ||, and optionally terminated by one of ;, &, or
+       <newline>.
+       Of these list operators, && and || have equal precedence, followed by ;
+       and &, which have equal precedence.
+       A sequence of one or more newlines may appear in a list  instead  of  a
+       semicolon to delimit commands.
+       If  a  command  is terminated by the control operator &, the shell exe-
+       cutes the command in the background in a subshell.  The shell does  not
+       wait  for  the command to finish, and the return status is 0.  Commands
+       separated by a ; are executed sequentially; the shell  waits  for  each
+       command  to terminate in turn.  The return status is the exit status of
+       the last command executed.
+       The control operators && and || denote AND lists and OR lists,  respec-
+       tively.  An AND list has the form
+              command1 && command2
+       command2  is  executed if, and only if, command1 returns an exit status
+       of zero.
+       An OR list has the form
+              command1 || command2
+       command2 is executed if and only if command1 returns  a  non-zero  exit
+       status.   The  return  status of AND and OR lists is the exit status of
+       the last command executed in the list.
+   Compound Commands
+       A compound command is one of the following:
+       (list) list is executed in a subshell environment (see  COMMAND  EXECU-
+              TION  ENVIRONMENT below).  Variable assignments and builtin com-
+              mands that affect the  shell's  environment  do  not  remain  in
+              effect  after  the  command completes.  The return status is the
+              exit status of list.
+       { list; }
+              list is simply executed in the current shell environment.   list
+              must  be  terminated with a newline or semicolon.  This is known
+              as a group command.  The return status is  the  exit  status  of
+              list.   Note that unlike the metacharacters ( and ), { and } are
+              reserved words and must occur where a reserved word is permitted
+              to  be  recognized.   Since they do not cause a word break, they
+              must be separated from list by whitespace.
+       ((expression))
+              The expression is evaluated according  to  the  rules  described
+              below  under ARITHMETIC EVALUATION.  If the value of the expres-
+              sion is non-zero, the return status is 0; otherwise  the  return
+              status is 1.  This is exactly equivalent to let "expression".
+       [[ expression ]]
+              Return  a  status  of  0 or 1 depending on the evaluation of the
+              conditional expression expression.  Expressions are composed  of
+              the  primaries  described  below  under CONDITIONAL EXPRESSIONS.
+              Word splitting and pathname expansion are not performed  on  the
+              words  between  the  [[  and  ]]; tilde expansion, parameter and
+              variable expansion, arithmetic expansion, command  substitution,
+              process  substitution,  and quote removal are performed.  Condi-
+              tional operators such as -f must be unquoted to be recognized as
+              primaries.
+              When  the  == and != operators are used, the string to the right
+              of the operator is considered a pattern and matched according to
+              the  rules described below under Pattern Matching.  If the shell
+              option nocasematch is enabled, the match  is  performed  without
+              regard  to  the case of alphabetic characters.  The return value
+              is 0 if the string matches (==) or does not match (!=) the  pat-
+              tern, and 1 otherwise.  Any part of the pattern may be quoted to
+              force it to be matched as a string.
+              An additional binary operator, =~, is available, with  the  same
+              precedence  as  ==  and  !=.  When it is used, the string to the
+              right of the operator is considered an extended regular  expres-
+              sion and matched accordingly (as in regex(3)).  The return value
+              is 0 if the string matches the pattern, and 1 otherwise.  If the
+              regular  expression  is syntactically incorrect, the conditional
+              expression's return value is 2.  If the shell option nocasematch
+              is enabled, the match is performed without regard to the case of
+              alphabetic  characters.   Substrings  matched  by  parenthesized
+              subexpressions  within  the  regular expression are saved in the
+              array variable BASH_REMATCH.  The element of  BASH_REMATCH  with
+              index 0 is the portion of the string matching the entire regular
+              expression.  The element of BASH_REMATCH with  index  n  is  the
+              portion  of the string matching the nth parenthesized subexpres-
+              sion.
+              Expressions may  be  combined  using  the  following  operators,
+              listed in decreasing order of precedence:
+              ( expression )
+                     Returns  the  value  of  expression.  This may be used to
+                     override the normal precedence of operators.
+              ! expression
+                     True if expression is false.
+              expression1 && expression2
+                     True if both expression1 and expression2 are true.
+              expression1 || expression2
+                     True if either expression1 or expression2 is true.
+              The && and || operators do not evaluate expression2 if the value
+              of  expression1  is  sufficient to determine the return value of
+              the entire conditional expression.
+       for name [ in word ] ; do list ; done
+              The list of words following in is expanded, generating a list of
+              items.  The variable name is set to each element of this list in
+              turn, and list is executed each time.  If the in word  is  omit-
+              ted,  the  for  command  executes  list once for each positional
+              parameter that is set (see PARAMETERS below).  The return status
+              is  the  exit  status of the last command that executes.  If the
+              expansion of the items following in results in an empty list, no
+              commands are executed, and the return status is 0.
+       for (( expr1 ; expr2 ; expr3 )) ; do list ; done
+              First, the arithmetic expression expr1 is evaluated according to
+              the rules described  below  under  ARITHMETIC  EVALUATION.   The
+              arithmetic  expression  expr2 is then evaluated repeatedly until
+              it evaluates to zero.  Each time expr2 evaluates to  a  non-zero
+              value,  list  is executed and the arithmetic expression expr3 is
+              evaluated.  If any expression is omitted, it behaves  as  if  it
+              evaluates to 1.  The return value is the exit status of the last
+              command in list that is executed, or false if any of the expres-
+              sions is invalid.
+       select name [ in word ] ; do list ; done
+              The list of words following in is expanded, generating a list of
+              items.  The set of expanded words is  printed  on  the  standard
+              error,  each  preceded  by a number.  If the in word is omitted,
+              the positional parameters are printed  (see  PARAMETERS  below).
+              The  PS3 prompt is then displayed and a line read from the stan-
+              dard input.  If the line consists of a number  corresponding  to
+              one  of  the  displayed  words, then the value of name is set to
+              that word.  If the line is empty, the words and prompt are  dis-
+              played again.  If EOF is read, the command completes.  Any other
+              value read causes name to be set to  null.   The  line  read  is
+              saved  in  the  variable REPLY.  The list is executed after each
+              selection until a break command is executed.  The exit status of
+              select  is the exit status of the last command executed in list,
+              or zero if no commands were executed.
+       case word in [ [(] pattern [ | pattern ] ... ) list ;; ] ... esac
+              A case command first expands word, and tries to match it against
+              each pattern in turn, using the same matching rules as for path-
+              name expansion (see Pathname  Expansion  below).   The  word  is
+              expanded  using  tilde  expansion, parameter and variable expan-
+              sion, arithmetic  substitution,  command  substitution,  process
+              substitution  and  quote  removal.   Each  pattern  examined  is
+              expanded using tilde expansion, parameter  and  variable  expan-
+              sion, arithmetic substitution, command substitution, and process
+              substitution.  If the shell option nocasematch is  enabled,  the
+              match  is  performed  without  regard  to the case of alphabetic
+              characters.  When a match is found, the  corresponding  list  is
+              executed.   After  the  first  match,  no subsequent matches are
+              attempted.  The exit status is zero if no pattern matches.  Oth-
+              erwise,  it  is  the exit status of the last command executed in
+              list.
+       if list; then list; [ elif list; then list; ] ... [ else list; ] fi
+              The if list is executed.  If its exit status is zero,  the  then
+              list  is  executed.   Otherwise,  each  elif list is executed in
+              turn, and if its exit status is  zero,  the  corresponding  then
+              list is executed and the command completes.  Otherwise, the else
+              list is executed, if present.  The exit status is the exit  sta-
+              tus of the last command executed, or zero if no condition tested
+              true.
+       while list; do list; done
+       until list; do list; done
+              The while command continuously executes the do list as  long  as
+              the  last  command  in list returns an exit status of zero.  The
+              until command is identical to the while command, except that the
+              test  is  negated;  the  do list is executed as long as the last
+              command in list returns a non-zero exit status.  The exit status
+              of  the  while and until commands is the exit status of the last
+              do list command executed, or zero if none was executed.
+   Shell Function Definitions
+       A shell function is an object that is called like a simple command  and
+       executes  a  compound  command with a new set of positional parameters.
+       Shell functions are declared as follows:
+       [ function ] name () compound-command [redirection]
+              This defines a function named name.  The reserved word  function
+              is  optional.   If  the  function reserved word is supplied, the
+              parentheses are optional.  The body of the function is the  com-
+              pound  command  compound-command  (see Compound Commands above).
+              That command is usually a list of commands between { and },  but
+              may  be  any command listed under Compound Commands above.  com-
+              pound-command is executed whenever name is specified as the name
+              of  a  simple command.  Any redirections (see REDIRECTION below)
+              specified when a function is  defined  are  performed  when  the
+              function  is executed.  The exit status of a function definition
+              is zero unless a syntax error occurs or a readonly function with
+              the same name already exists.  When executed, the exit status of
+              a function is the exit status of the last  command  executed  in
+              the body.  (See FUNCTIONS below.)
+COMMENTS
+       In a non-interactive shell, or an interactive shell in which the inter-
+       active_comments option to the  shopt  builtin  is  enabled  (see  SHELL
+       BUILTIN  COMMANDS  below), a word beginning with # causes that word and
+       all remaining characters on that line to be  ignored.   An  interactive
+       shell  without  the  interactive_comments option enabled does not allow
+       comments.  The interactive_comments option is on by default in interac-
+       tive shells.
+QUOTING
+       Quoting  is used to remove the special meaning of certain characters or
+       words to the shell.  Quoting can be used to disable  special  treatment
+       for special characters, to prevent reserved words from being recognized
+       as such, and to prevent parameter expansion.
+       Each of the metacharacters listed above under DEFINITIONS  has  special
+       meaning to the shell and must be quoted if it is to represent itself.
+       When  the command history expansion facilities are being used (see HIS-
+       TORY EXPANSION below), the history expansion character, usually !, must
+       be quoted to prevent history expansion.
+       There  are  three  quoting  mechanisms:  the  escape  character, single
+       quotes, and double quotes.
+       A non-quoted backslash (\) is the escape character.  It  preserves  the
+       literal value of the next character that follows, with the exception of
+       <newline>.  If a \<newline> pair appears,  and  the  backslash  is  not
+       itself  quoted,  the \<newline> is treated as a line continuation (that
+       is, it is removed from the input stream and effectively ignored).
+       Enclosing characters in single quotes preserves the  literal  value  of
+       each character within the quotes.  A single quote may not occur between
+       single quotes, even when preceded by a backslash.
+       Enclosing characters in double quotes preserves the  literal  value  of
+       all  characters  within the quotes, with the exception of $, `, \, and,
+       when history expansion is enabled, !.  The characters $  and  `  retain
+       their  special meaning within double quotes.  The backslash retains its
+       special meaning only when followed by one of the following  characters:
+       $,  `,  ", \, or <newline>.  A double quote may be quoted within double
+       quotes by preceding it with a backslash.  If enabled, history expansion
+       will  be  performed  unless an !  appearing in double quotes is escaped
+       using a backslash.  The backslash preceding the !  is not removed.
+       The special parameters * and @ have  special  meaning  when  in  double
+       quotes (see PARAMETERS below).
+       Words of the form $'string' are treated specially.  The word expands to
+       string, with backslash-escaped characters replaced as specified by  the
+       ANSI  C  standard.  Backslash escape sequences, if present, are decoded
+       as follows:
+              \a     alert (bell)
+              \b     backspace
+              \e     an escape character
+              \f     form feed
+              \n     new line
+              \r     carriage return
+              \t     horizontal tab
+              \v     vertical tab
+              \\     backslash
+              \'     single quote
+              \nnn   the eight-bit character whose value is  the  octal  value
+                     nnn (one to three digits)
+              \xHH   the  eight-bit  character  whose value is the hexadecimal
+                     value HH (one or two hex digits)
+              \cx    a control-x character
+       The expanded result is single-quoted, as if the  dollar  sign  had  not
+       been present.
+       A  double-quoted  string  preceded  by a dollar sign ($) will cause the
+       string to be translated according to the current locale.  If  the  cur-
+       rent  locale  is C or POSIX, the dollar sign is ignored.  If the string
+       is translated and replaced, the replacement is double-quoted.
+PARAMETERS
+       A parameter is an entity that stores values.  It can be a name, a  num-
+       ber, or one of the special characters listed below under Special Param-
+       eters.  A variable is a parameter denoted by a name.  A variable has  a
+       value  and  zero or more attributes.  Attributes are assigned using the
+       declare builtin command (see declare below in SHELL BUILTIN  COMMANDS).
+       A parameter is set if it has been assigned a value.  The null string is
+       a valid value.  Once a variable is set, it may be unset only  by  using
+       the unset builtin command (see SHELL BUILTIN COMMANDS below).
+       A variable may be assigned to by a statement of the form
+              name=[value]
+       If  value  is not given, the variable is assigned the null string.  All
+       values undergo tilde expansion, parameter and variable expansion,  com-
+       mand  substitution, arithmetic expansion, and quote removal (see EXPAN-
+       SION below).  If the variable has its integer attribute set, then value
+       is evaluated as an arithmetic expression even if the $((...)) expansion
+       is not used (see Arithmetic Expansion below).  Word  splitting  is  not
+       performed,  with the exception of "$@" as explained below under Special
+       Parameters.  Pathname expansion is not  performed.   Assignment  state-
+       ments  may  also  appear  as  arguments to the alias, declare, typeset,
+       export, readonly, and local builtin commands.
+       In the context where an assignment statement is assigning a value to  a
+       shell variable or array index, the += operator can be used to append to
+       or add to the variable's previous value.  When += is applied to a vari-
+       able  for  which the integer attribute has been set, value is evaluated
+       as an arithmetic expression and added to the variable's current  value,
+       which is also evaluated.  When += is applied to an array variable using
+       compound assignment (see Arrays below), the  variable's  value  is  not
+       unset (as it is when using =), and new values are appended to the array
+       beginning at one greater than the array's maximum index.  When  applied
+       to  a  string-valued  variable,  value  is expanded and appended to the
+       variable's value.
+   Positional Parameters
+       A positional parameter is a parameter denoted by one  or  more  digits,
+       other than the single digit 0.  Positional parameters are assigned from
+       the shell's arguments when it is invoked, and may be  reassigned  using
+       the  set builtin command.  Positional parameters may not be assigned to
+       with assignment statements.  The positional parameters are  temporarily
+       replaced when a shell function is executed (see FUNCTIONS below).
+       When  a  positional parameter consisting of more than a single digit is
+       expanded, it must be enclosed in braces (see EXPANSION below).
+   Special Parameters
+       The shell treats several parameters specially.   These  parameters  may
+       only be referenced; assignment to them is not allowed.
+       *      Expands  to  the positional parameters, starting from one.  When
+              the expansion occurs within double quotes, it expands to a  sin-
+              gle word with the value of each parameter separated by the first
+              character of the IFS special variable.  That is, "$*" is equiva-
+              lent to "$1c$2c...", where c is the first character of the value
+              of the IFS variable.  If IFS is unset, the parameters are  sepa-
+              rated  by  spaces.   If  IFS  is null, the parameters are joined
+              without intervening separators.
+       @      Expands to the positional parameters, starting from  one.   When
+              the  expansion  occurs  within  double  quotes,  each  parameter
+              expands to a separate word.  That is, "$@" is equivalent to "$1"
+              "$2"  ...   If the double-quoted expansion occurs within a word,
+              the expansion of the first parameter is joined with  the  begin-
+              ning  part  of  the original word, and the expansion of the last
+              parameter is joined with the last part  of  the  original  word.
+              When  there  are no positional parameters, "$@" and $@ expand to
+              nothing (i.e., they are removed).
+       #      Expands to the number of positional parameters in decimal.
+       ?      Expands to the status of the most recently  executed  foreground
+              pipeline.
+       -      Expands  to  the  current option flags as specified upon invoca-
+              tion, by the set builtin command, or  those  set  by  the  shell
+              itself (such as the -i option).
+       $      Expands  to  the  process ID of the shell.  In a () subshell, it
+              expands to the process ID of the current  shell,  not  the  sub-
+              shell.
+       !      Expands  to  the  process ID of the most recently executed back-
+              ground (asynchronous) command.
+      Expands to the name of the shell or shell script.  This  is  set
+              at shell initialization.  If bash is invoked with a file of com-
+              mands, $0 is set to the name of that file.  If bash  is  started
+              with  the  -c option, then $0 is set to the first argument after
+              the string to be executed, if one is present.  Otherwise, it  is
+              set  to  the file name used to invoke bash, as given by argument
+              zero.
+       _      At shell startup, set to the absolute pathname  used  to  invoke
+              the  shell or shell script being executed as passed in the envi-
+              ronment or argument list.  Subsequently,  expands  to  the  last
+              argument  to the previous command, after expansion.  Also set to
+              the full pathname used  to  invoke  each  command  executed  and
+              placed in the environment exported to that command.  When check-
+              ing mail, this parameter holds the name of the  mail  file  cur-
+              rently being checked.
+   Shell Variables
+       The following variables are set by the shell:
+       BASH   Expands  to  the  full file name used to invoke this instance of
+              bash.
+       BASH_ARGC
+              An array variable whose values are the number of  parameters  in
+              each frame of the current bash execution call stack.  The number
+              of parameters to  the  current  subroutine  (shell  function  or
+              script  executed  with  . or source) is at the top of the stack.
+              When a subroutine is executed, the number of  parameters  passed
+              is pushed onto BASH_ARGC.  The shell sets BASH_ARGC only when in
+              extended debugging mode (see the  description  of  the  extdebug
+              option to the shopt builtin below)
+       BASH_ARGV
+              An  array  variable containing all of the parameters in the cur-
+              rent bash execution call stack.  The final parameter of the last
+              subroutine  call is at the top of the stack; the first parameter
+              of the initial call is at the bottom.  When a subroutine is exe-
+              cuted,  the  parameters supplied are pushed onto BASH_ARGV.  The
+              shell sets BASH_ARGV only when in extended debugging  mode  (see
+              the  description  of  the  extdebug  option to the shopt builtin
+              below)
+       BASH_COMMAND
+              The command currently being executed or about  to  be  executed,
+              unless the shell is executing a command as the result of a trap,
+              in which case it is the command executing at  the  time  of  the
+              trap.
+       BASH_EXECUTION_STRING
+              The command argument to the -c invocation option.
+       BASH_LINENO
+              An  array  variable whose members are the line numbers in source
+              files   corresponding    to    each    member    of    FUNCNAME.
+              ${BASH_LINENO[$i]}  is  the line number in the source file where
+              ${FUNCNAME[$ifP]} was called.   The  corresponding  source  file
+              name  is  ${BASH_SOURCE[$i]}.   Use LINENO to obtain the current
+              line number.
+       BASH_REMATCH
+              An array variable whose members are assigned by  the  =~  binary
+              operator  to the [[ conditional command.  The element with index
+is the portion of  the  string  matching  the  entire  regular
+              expression.   The  element  with  index  n is the portion of the
+              string matching the nth parenthesized subexpression.  This vari-
+              able is read-only.
+       BASH_SOURCE
+              An  array variable whose members are the source filenames corre-
+              sponding to the elements in the FUNCNAME array variable.
+       BASH_SUBSHELL
+              Incremented by one each time a subshell or subshell  environment
+              is spawned.  The initial value is 0.
+       BASH_VERSINFO
+              A readonly array variable whose members hold version information
+              for this instance of bash.  The values  assigned  to  the  array
+              members are as follows:
+              BASH_VERSINFO[0]        The  major version number (the release).
+              BASH_VERSINFO[1]        The minor version number (the  version).
+              BASH_VERSINFO[2]        The patch level.
+              BASH_VERSINFO[3]        The build version.
+              BASH_VERSINFO[4]        The release status (e.g., beta1).
+              BASH_VERSINFO[5]        The value of MACHTYPE.
+       BASH_VERSION
+              Expands  to  a string describing the version of this instance of
+              bash.
+       COMP_CWORD
+              An index into ${COMP_WORDS} of the word containing  the  current
+              cursor position.  This variable is available only in shell func-
+              tions invoked by the  programmable  completion  facilities  (see
+              Programmable Completion below).
+       COMP_LINE
+              The  current  command  line.  This variable is available only in
+              shell functions  and  external  commands  invoked  by  the  pro-
+              grammable  completion  facilities  (see  Programmable Completion
+              below).
+       COMP_POINT
+              The index of the current cursor position relative to the  begin-
+              ning  of the current command.  If the current cursor position is
+              at the end of the current command, the value of this variable is
+              equal  to  ${#COMP_LINE}.   This  variable  is available only in
+              shell functions  and  external  commands  invoked  by  the  pro-
+              grammable  completion  facilities  (see  Programmable Completion
+              below).
+       COMP_WORDBREAKS
+              The set of characters that the Readline library treats  as  word
+              separators  when performing word completion.  If COMP_WORDBREAKS
+              is unset, it loses its special properties, even if it is  subse-
+              quently reset.
+       COMP_WORDS
+              An  array variable (see Arrays below) consisting of the individ-
+              ual words in the current command line.  The words are  split  on
+              shell  metacharacters  as  the shell parser would separate them.
+              This variable is available only in shell  functions  invoked  by
+              the programmable completion facilities (see Programmable Comple-
+              tion below).
+       DIRSTACK
+              An array variable (see Arrays below) containing the current con-
+              tents  of  the directory stack.  Directories appear in the stack
+              in the order they are displayed by the dirs builtin.   Assigning
+              to members of this array variable may be used to modify directo-
+              ries already in the stack, but the pushd and popd builtins  must
+              be used to add and remove directories.  Assignment to this vari-
+              able will not change the  current  directory.   If  DIRSTACK  is
+              unset,  it  loses  its  special properties, even if it is subse-
+              quently reset.
+       EUID   Expands to the effective user ID of the current  user,  initial-
+              ized at shell startup.  This variable is readonly.
+       FUNCNAME
+              An  array  variable  containing the names of all shell functions
+              currently in the execution call stack.  The element with index 0
+              is the name of any currently-executing shell function.  The bot-
+              tom-most element is "main".  This variable exists  only  when  a
+              shell  function  is  executing.  Assignments to FUNCNAME have no
+              effect and return an error status.  If  FUNCNAME  is  unset,  it
+              loses  its special properties, even if it is subsequently reset.
+       GROUPS An array variable containing the list of  groups  of  which  the
+              current  user is a member.  Assignments to GROUPS have no effect
+              and return an error status.  If GROUPS is unset,  it  loses  its
+              special properties, even if it is subsequently reset.
+       HISTCMD
+              The history number, or index in the history list, of the current
+              command.  If HISTCMD is unset, it loses its special  properties,
+              even if it is subsequently reset.
+       HOSTNAME
+              Automatically set to the name of the current host.
+       HOSTTYPE
+              Automatically  set  to a string that uniquely describes the type
+              of machine on which bash is executing.  The default  is  system-
+              dependent.
+       LINENO Each  time this parameter is referenced, the shell substitutes a
+              decimal number representing the current sequential  line  number
+              (starting  with  1)  within a script or function.  When not in a
+              script or function, the value substituted is not  guaranteed  to
+              be meaningful.  If LINENO is unset, it loses its special proper-
+              ties, even if it is subsequently reset.
+       MACHTYPE
+              Automatically set to a string that fully  describes  the  system
+              type  on  which  bash is executing, in the standard GNU cpu-com-
+              pany-system format.  The default is system-dependent.
+       OLDPWD The previous working directory as set by the cd command.
+       OPTARG The value of the last option argument processed by  the  getopts
+              builtin command (see SHELL BUILTIN COMMANDS below).
+       OPTIND The  index  of  the next argument to be processed by the getopts
+              builtin command (see SHELL BUILTIN COMMANDS below).
+       OSTYPE Automatically set to a string that describes the operating  sys-
+              tem  on  which  bash is executing.  The default is system-depen-
+              dent.
+       PIPESTATUS
+              An array variable (see Arrays below) containing a list  of  exit
+              status  values  from the processes in the most-recently-executed
+              foreground pipeline (which may contain only a single command).
+       PPID   The process ID of the shell's parent.  This  variable  is  read-
+              only.
+       PWD    The current working directory as set by the cd command.
+       RANDOM Each time this parameter is referenced, a random integer between
+and 32767 is generated.  The sequence of random numbers may be
+              initialized by assigning a value to RANDOM.  If RANDOM is unset,
+              it loses its special properties,  even  if  it  is  subsequently
+              reset.
+       REPLY  Set  to  the line of input read by the read builtin command when
+              no arguments are supplied.
+       SECONDS
+              Each time this parameter is referenced, the  number  of  seconds
+              since  shell  invocation is returned.  If a value is assigned to
+              SECONDS, the value returned upon subsequent  references  is  the
+              number  of seconds since the assignment plus the value assigned.
+              If SECONDS is unset, it loses its special properties, even if it
+              is subsequently reset.
+       SHELLOPTS
+              A  colon-separated  list of enabled shell options.  Each word in
+              the list is a valid argument  for  the  -o  option  to  the  set
+              builtin command (see SHELL BUILTIN COMMANDS below).  The options
+              appearing in SHELLOPTS are those reported as on by set  -o.   If
+              this  variable  is  in the environment when bash starts up, each
+              shell option in the list will  be  enabled  before  reading  any
+              startup files.  This variable is read-only.
+       SHLVL  Incremented by one each time an instance of bash is started.
+       UID    Expands to the user ID of the current user, initialized at shell
+              startup.  This variable is readonly.
+       The following variables are used by the shell.   In  some  cases,  bash
+       assigns a default value to a variable; these cases are noted below.
+       BASH_ENV
+              If  this parameter is set when bash is executing a shell script,
+              its value is interpreted as a filename  containing  commands  to
+              initialize the shell, as in ~/.bashrc.  The value of BASH_ENV is
+              subjected to  parameter  expansion,  command  substitution,  and
+              arithmetic  expansion  before  being interpreted as a file name.
+              PATH is not used to search for the resultant file name.
+       CDPATH The search path for the cd command.  This is  a  colon-separated
+              list  of  directories  in  which the shell looks for destination
+              directories specified by the cd  command.   A  sample  value  is
+              ".:~:/usr".
+       COLUMNS
+              Used  by  the  select  builtin command to determine the terminal
+              width when printing selection  lists.   Automatically  set  upon
+              receipt of a SIGWINCH.
+       COMPREPLY
+              An array variable from which bash reads the possible completions
+              generated by a shell function invoked by the  programmable  com-
+              pletion facility (see Programmable Completion below).
+       EMACS  If  bash  finds  this variable in the environment when the shell
+              starts with value "t", it assumes that the shell is  running  in
+              an emacs shell buffer and disables line editing.
+       FCEDIT The default editor for the fc builtin command.
+       FIGNORE
+              A  colon-separated  list  of  suffixes to ignore when performing
+              filename completion (see READLINE below).  A filename whose suf-
+              fix  matches  one of the entries in FIGNORE is excluded from the
+              list of matched filenames.  A sample value is ".o:~".
+       GLOBIGNORE
+              A colon-separated list of patterns defining the set of filenames
+              to be ignored by pathname expansion.  If a filename matched by a
+              pathname expansion pattern also matches one of the  patterns  in
+              GLOBIGNORE, it is removed from the list of matches.
+       HISTCONTROL
+              A  colon-separated  list  of values controlling how commands are
+              saved on the history list.   If  the  list  of  values  includes
+              ignorespace,  lines  which  begin with a space character are not
+              saved in the history list.  A value of ignoredups  causes  lines
+              matching the previous history entry to not be saved.  A value of
+              ignoreboth is shorthand for ignorespace and ignoredups.  A value
+              of erasedups causes all previous lines matching the current line
+              to be removed from the history list before that line  is  saved.
+              Any  value  not in the above list is ignored.  If HISTCONTROL is
+              unset, or does not include a valid value, all lines read by  the
+              shell parser are saved on the history list, subject to the value
+              of HISTIGNORE.  The second and subsequent lines of a  multi-line
+              compound  command  are  not tested, and are added to the history
+              regardless of the value of HISTCONTROL.
+       HISTFILE
+              The name of the file in which command history is saved (see HIS-
+              TORY  below).   The default value is ~/.bash_history.  If unset,
+              the command history is  not  saved  when  an  interactive  shell
+              exits.
+       HISTFILESIZE
+              The maximum number of lines contained in the history file.  When
+              this variable is assigned a value, the  history  file  is  trun-
+              cated,  if necessary, by removing the oldest entries, to contain
+              no more than that number of lines.  The default  value  is  500.
+              The history file is also truncated to this size after writing it
+              when an interactive shell exits.
+       HISTIGNORE
+              A colon-separated list of patterns used to decide which  command
+              lines  should  be  saved  on  the history list.  Each pattern is
+              anchored at the beginning of the line and must  match  the  com-
+              plete  line  (no  implicit  `*'  is  appended).  Each pattern is
+              tested against the line after the checks specified  by  HISTCON-
+              TROL  are  applied.   In  addition  to  the normal shell pattern
+              matching characters, `&' matches the previous history line.  `&'
+              may  be  escaped  using  a  backslash;  the backslash is removed
+              before attempting a match.  The second and subsequent lines of a
+              multi-line compound command are not tested, and are added to the
+              history regardless of the value of HISTIGNORE.
+       HISTSIZE
+              The number of commands to remember in the command  history  (see
+              HISTORY below).  The default value is 500.
+       HISTTIMEFORMAT
+              If  this  variable  is  set and not null, its value is used as a
+              format string for strftime(3) to print the time stamp associated
+              with  each  history  entry displayed by the history builtin.  If
+              this variable is set, time stamps are  written  to  the  history
+              file so they may be preserved across shell sessions.
+       HOME   The home directory of the current user; the default argument for
+              the cd builtin command.  The value of this variable is also used
+              when performing tilde expansion.
+       HOSTFILE
+              Contains  the  name  of  a file in the same format as /etc/hosts
+              that should be read when the shell needs to complete a hostname.
+              The  list  of possible hostname completions may be changed while
+              the shell is running;  the  next  time  hostname  completion  is
+              attempted  after the value is changed, bash adds the contents of
+              the new file to the existing list.  If HOSTFILE is set, but  has
+              no value, bash attempts to read /etc/hosts to obtain the list of
+              possible hostname completions.   When  HOSTFILE  is  unset,  the
+              hostname list is cleared.
+       IFS    The  Internal  Field  Separator  that is used for word splitting
+              after expansion and to split lines  into  words  with  the  read
+              builtin  command.   The  default  value  is  ``<space><tab><new-
+              line>''.
+       IGNOREEOF
+              Controls the action of an interactive shell on receipt of an EOF
+              character as the sole input.  If set, the value is the number of
+              consecutive EOF characters which must  be  typed  as  the  first
+              characters  on an input line before bash exits.  If the variable
+              exists but does not have a numeric value, or has no  value,  the
+              default  value  is  10.  If it does not exist, EOF signifies the
+              end of input to the shell.
+       INPUTRC
+              The filename for  the  readline  startup  file,  overriding  the
+              default of ~/.inputrc (see READLINE below).
+       LANG   Used  to  determine  the  locale  category  for any category not
+              specifically selected with a variable starting with LC_.
+       LC_ALL This variable overrides the value of  LANG  and  any  other  LC_
+              variable specifying a locale category.
+       LC_COLLATE
+              This  variable  determines the collation order used when sorting
+              the results of pathname expansion, and determines  the  behavior
+              of   range   expressions,  equivalence  classes,  and  collating
+              sequences within pathname expansion and pattern matching.
+       LC_CTYPE
+              This variable determines the interpretation  of  characters  and
+              the  behavior of character classes within pathname expansion and
+              pattern matching.
+       LC_MESSAGES
+              This variable determines the locale used  to  translate  double-
+              quoted strings preceded by a $.
+       LC_NUMERIC
+              This  variable  determines  the  locale category used for number
+              formatting.
+       LINES  Used by the select  builtin  command  to  determine  the  column
+              length  for  printing  selection  lists.  Automatically set upon
+              receipt of a SIGWINCH.
+       MAIL   If this parameter is set to a file name and the  MAILPATH  vari-
+              able is not set, bash informs the user of the arrival of mail in
+              the specified file.
+       MAILCHECK
+              Specifies how often (in seconds)  bash  checks  for  mail.   The
+              default  is  60 seconds.  When it is time to check for mail, the
+              shell does so before displaying the  primary  prompt.   If  this
+              variable  is  unset,  or  set  to  a  value that is not a number
+              greater than or equal to zero, the shell disables mail checking.
+       MAILPATH
+              A  colon-separated  list  of  file names to be checked for mail.
+              The message to be printed when mail arrives in a particular file
+              may  be  specified  by separating the file name from the message
+              with a `?'.  When used in the text of the message, $_ expands to
+              the name of the current mailfile.  Example:
+              MAILPATH='/var/mail/bfox?"You  have  mail":~/shell-mail?"$_  has
+              mail!"'
+              Bash supplies a default value for this variable, but  the  loca-
+              tion  of  the  user  mail files that it uses is system dependent
+              (e.g., /var/mail/$USER).
+       OPTERR If set to the value 1, bash displays error messages generated by
+              the  getopts builtin command (see SHELL BUILTIN COMMANDS below).
+              OPTERR is initialized to 1 each time the shell is invoked  or  a
+              shell script is executed.
+       PATH   The  search  path for commands.  It is a colon-separated list of
+              directories in which the shell looks for commands  (see  COMMAND
+              EXECUTION  below).   A  zero-length (null) directory name in the
+              value of PATH indicates the current directory.  A null directory
+              name  may  appear  as  two  adjacent colons, or as an initial or
+              trailing colon.  The default path is  system-dependent,  and  is
+              set  by  the administrator who installs bash.  A common value is
+              ``/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin''.
+       POSIXLY_CORRECT
+              If this variable is in the environment  when  bash  starts,  the
+              shell  enters posix mode before reading the startup files, as if
+              the --posix invocation option had been supplied.  If it  is  set
+              while  the  shell is running, bash enables posix mode, as if the
+              command set -o posix had been executed.
+       PROMPT_COMMAND
+              If set, the value is executed as a command prior to issuing each
+              primary prompt.
+       PS1    The  value  of  this parameter is expanded (see PROMPTING below)
+              and used as the primary prompt string.   The  default  value  is
+              ``\s-\v\$ ''.
+       PS2    The  value of this parameter is expanded as with PS1 and used as
+              the secondary prompt string.  The default is ``> ''.
+       PS3    The value of this parameter is used as the prompt for the select
+              command (see SHELL GRAMMAR above).
+       PS4    The  value  of  this  parameter  is expanded as with PS1 and the
+              value is printed before each command  bash  displays  during  an
+              execution  trace.  The first character of PS4 is replicated mul-
+              tiple times, as necessary, to indicate multiple levels of  indi-
+              rection.  The default is ``+ ''.
+       SHELL  The full pathname to the shell is kept in this environment vari-
+              able.  If it is not set when the shell starts, bash  assigns  to
+              it the full pathname of the current user's login shell.
+       TIMEFORMAT
+              The  value of this parameter is used as a format string specify-
+              ing how the timing information for pipelines prefixed  with  the
+              time  reserved word should be displayed.  The % character intro-
+              duces an escape sequence that is expanded to  a  time  value  or
+              other  information.  The escape sequences and their meanings are
+              as follows; the braces denote optional portions.
+              %%        A literal %.
+              %[p][l]R  The elapsed time in seconds.
+              %[p][l]U  The number of CPU seconds spent in user mode.
+              %[p][l]S  The number of CPU seconds spent in system mode.
+              %P        The CPU percentage, computed as (%U + %S) / %R.
+              The optional p is a digit specifying the precision,  the  number
+              of fractional digits after a decimal point.  A value of 0 causes
+              no decimal point or fraction to be output.  At most three places
+              after  the  decimal  point may be specified; values of p greater
+              than 3 are changed to 3.  If p is not specified, the value 3  is
+              used.
+              The  optional l specifies a longer format, including minutes, of
+              the form MMmSS.FFs.  The value of p determines  whether  or  not
+              the fraction is included.
+              If  this  variable  is not set, bash acts as if it had the value
+              $'\nreal\t%3lR\nuser\t%3lU\nsys%3lS'.  If the value is null,  no
+              timing  information  is  displayed.  A trailing newline is added
+              when the format string is displayed.
+       TMOUT  If set to a value greater than zero, TMOUT  is  treated  as  the
+              default timeout for the read builtin.  The select command termi-
+              nates if input does not arrive after TMOUT seconds when input is
+              coming  from  a terminal.  In an interactive shell, the value is
+              interpreted as the number of seconds to  wait  for  input  after
+              issuing  the  primary prompt.  Bash terminates after waiting for
+              that number of seconds if input does not arrive.
+       TMPDIR If set, Bash uses its value as the name of a directory in  which
+              Bash creates temporary files for the shell's use.
+       auto_resume
+              This variable controls how the shell interacts with the user and
+              job control.  If this variable is set, single word  simple  com-
+              mands without redirections are treated as candidates for resump-
+              tion of an existing stopped job.  There is no ambiguity allowed;
+              if  there  is more than one job beginning with the string typed,
+              the job most recently accessed  is  selected.   The  name  of  a
+              stopped  job, in this context, is the command line used to start
+              it.  If set to the value exact, the string supplied  must  match
+              the  name  of  a  stopped  job exactly; if set to substring, the
+              string supplied needs to match a substring  of  the  name  of  a
+              stopped  job.  The substring value provides functionality analo-
+              gous to the %?  job identifier (see JOB CONTROL below).  If  set
+              to  any  other  value, the supplied string must be a prefix of a
+              stopped job's name; this provides functionality analogous to the
+              %string job identifier.
+       histchars
+              The  two or three characters which control history expansion and
+              tokenization (see HISTORY EXPANSION below).  The first character
+              is  the history expansion character, the character which signals
+              the start of a history  expansion,  normally  `!'.   The  second
+              character  is the quick substitution character, which is used as
+              shorthand for re-running the previous command  entered,  substi-
+              tuting  one  string  for another in the command.  The default is
+              `^'.  The optional third character is the character which  indi-
+              cates  that the remainder of the line is a comment when found as
+              the first character of a word, normally `#'.  The  history  com-
+              ment character causes history substitution to be skipped for the
+              remaining words on the line.  It does not necessarily cause  the
+              shell parser to treat the rest of the line as a comment.
+   Arrays
+       Bash  provides  one-dimensional  array  variables.  Any variable may be
+       used as an array; the declare builtin will explicitly declare an array.
+       There  is no maximum limit on the size of an array, nor any requirement
+       that members be indexed or assigned contiguously.  Arrays  are  indexed
+       using integers and are zero-based.
+       An  array is created automatically if any variable is assigned to using
+       the syntax name[subscript]=value.   The  subscript  is  treated  as  an
+       arithmetic  expression  that  must evaluate to a number greater than or
+       equal to zero.  To explicitly declare an array,  use  declare  -a  name
+       (see SHELL BUILTIN COMMANDS below).  declare -a name[subscript] is also
+       accepted; the subscript is ignored.  Attributes may be specified for an
+       array variable using the declare and readonly builtins.  Each attribute
+       applies to all members of an array.
+       Arrays  are  assigned  to  using  compound  assignments  of  the   form
+       name=(value1  ...  valuen),  where  each  value  is  of  the form [sub-
+       script]=string.  Only string is required.  If the optional brackets and
+       subscript  are supplied, that index is assigned to; otherwise the index
+       of the element assigned is the last index assigned to by the  statement
+       plus  one.   Indexing  starts at zero.  This syntax is also accepted by
+       the declare builtin.  Individual array  elements  may  be  assigned  to
+       using the name[subscript]=value syntax introduced above.
+       Any  element  of  an  array may be referenced using ${name[subscript]}.
+       The braces are required to avoid conflicts with pathname expansion.  If
+       subscript  is  @  or *, the word expands to all members of name.  These
+       subscripts differ only when the word appears within double quotes.   If
+       the word is double-quoted, ${name[*]} expands to a single word with the
+       value of each array member separated by the first character of the  IFS
+       special variable, and ${name[@]} expands each element of name to a sep-
+       arate word.  When there are no array  members,  ${name[@]}  expands  to
+       nothing.   If  the  double-quoted  expansion  occurs within a word, the
+       expansion of the first parameter is joined with the beginning  part  of
+       the  original  word,  and the expansion of the last parameter is joined
+       with the last part of the original word.   This  is  analogous  to  the
+       expansion  of  the  special  parameters * and @ (see Special Parameters
+       above).  ${#name[subscript]}  expands  to  the  length  of  ${name[sub-
+       script]}.   If subscript is * or @, the expansion is the number of ele-
+       ments in the array.  Referencing an array variable without a  subscript
+       is equivalent to referencing element zero.
+       The  unset  builtin  is  used to destroy arrays.  unset name[subscript]
+       destroys the array element at index subscript.  Care must be  taken  to
+       avoid unwanted side effects caused by filename generation.  unset name,
+       where name is an array, or unset name[subscript], where subscript is  *
+       or @, removes the entire array.
+       The  declare,  local,  and readonly builtins each accept a -a option to
+       specify an array.  The read builtin accepts a -a  option  to  assign  a
+       list  of  words  read from the standard input to an array.  The set and
+       declare builtins display array values in a way that allows them  to  be
+       reused as assignments.
+EXPANSION
+       Expansion is performed on the command line after it has been split into
+       words.  There are seven kinds of expansion performed: brace  expansion,
+       tilde  expansion,  parameter  and variable expansion, command substitu-
+       tion, arithmetic expansion, word splitting, and pathname expansion.
+       The order of expansions is: brace expansion, tilde  expansion,  parame-
+       ter,  variable  and arithmetic expansion and command substitution (done
+       in a left-to-right fashion), word splitting, and pathname expansion.
+       On systems that can support it, there is an additional expansion avail-
+       able: process substitution.
+       Only brace expansion, word splitting, and pathname expansion can change
+       the number of words of the expansion; other expansions expand a  single
+       word  to a single word.  The only exceptions to this are the expansions
+       of "$@" and "${name[@]}" as explained above (see PARAMETERS).
+   Brace Expansion
+       Brace expansion is a mechanism by which arbitrary strings may be gener-
+       ated.   This  mechanism is similar to pathname expansion, but the file-
+       names generated need not exist.  Patterns to be brace expanded take the
+       form of an optional preamble, followed by either a series of comma-sep-
+       arated strings or a sequence expression between a pair of braces,  fol-
+       lowed  by  an  optional  postscript.   The preamble is prefixed to each
+       string contained within the braces, and the postscript is then appended
+       to each resulting string, expanding left to right.
+       Brace  expansions  may  be nested.  The results of each expanded string
+       are not sorted;  left  to  right  order  is  preserved.   For  example,
+       a{d,c,b}e expands into `ade ace abe'.
+       A  sequence  expression takes the form {x..y}, where x and y are either
+       integers or single characters.  When integers are supplied, the expres-
+       sion  expands  to each number between x and y, inclusive.  When charac-
+       ters are supplied, the expression expands  to  each  character  lexico-
+       graphically between x and y, inclusive.  Note that both x and y must be
+       of the same type.
+       Brace expansion is performed before any other expansions, and any char-
+       acters  special to other expansions are preserved in the result.  It is
+       strictly textual.  Bash does not apply any syntactic interpretation  to
+       the context of the expansion or the text between the braces.
+       A  correctly-formed  brace  expansion must contain unquoted opening and
+       closing braces, and at least one unquoted comma  or  a  valid  sequence
+       expression.   Any incorrectly formed brace expansion is left unchanged.
+       A { or , may be quoted with a backslash to prevent its being considered
+       part  of  a brace expression.  To avoid conflicts with parameter expan-
+       sion, the string ${ is not considered eligible for brace expansion.
+       This construct is typically used as shorthand when the common prefix of
+       the strings to be generated is longer than in the above example:
+              mkdir /usr/local/src/bash/{old,new,dist,bugs}
+       or
+              chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}}
+       Brace  expansion  introduces  a  slight incompatibility with historical
+       versions of sh.  sh does not treat opening or closing braces  specially
+       when  they  appear as part of a word, and preserves them in the output.
+       Bash removes braces from words as a  consequence  of  brace  expansion.
+       For  example,  a word entered to sh as file{1,2} appears identically in
+       the output.  The same word is output as file1 file2 after expansion  by
+       bash.   If strict compatibility with sh is desired, start bash with the
+       +B option or disable brace expansion with the +B option to the set com-
+       mand (see SHELL BUILTIN COMMANDS below).
+   Tilde Expansion
+       If  a  word  begins  with an unquoted tilde character (`~'), all of the
+       characters preceding the first unquoted slash (or  all  characters,  if
+       there  is no unquoted slash) are considered a tilde-prefix.  If none of
+       the characters in the tilde-prefix are quoted, the  characters  in  the
+       tilde-prefix  following the tilde are treated as a possible login name.
+       If this login name is the null string, the tilde is replaced  with  the
+       value  of  the shell parameter HOME.  If HOME is unset, the home direc-
+       tory of the user executing the shell is  substituted  instead.   Other-
+       wise,  the  tilde-prefix is replaced with the home directory associated
+       with the specified login name.
+       If the tilde-prefix is a `~+', the value  of  the  shell  variable  PWD
+       replaces the tilde-prefix.  If the tilde-prefix is a `~-', the value of
+       the shell variable OLDPWD, if it is set, is substituted.  If the  char-
+       acters  following  the tilde in the tilde-prefix consist of a number N,
+       optionally prefixed by a `+' or a `-',  the  tilde-prefix  is  replaced
+       with the corresponding element from the directory stack, as it would be
+       displayed by the dirs builtin invoked with the tilde-prefix as an argu-
+       ment.   If  the characters following the tilde in the tilde-prefix con-
+       sist of a number without a leading `+' or `-', `+' is assumed.
+       If the login name is invalid, or the tilde expansion fails, the word is
+       unchanged.
+       Each variable assignment is checked for unquoted tilde-prefixes immedi-
+       ately following a : or the first =.  In these cases, tilde expansion is
+       also  performed.   Consequently,  one may use file names with tildes in
+       assignments to PATH, MAILPATH, and CDPATH, and the  shell  assigns  the
+       expanded value.
+   Parameter Expansion
+       The `$' character introduces parameter expansion, command substitution,
+       or arithmetic expansion.  The parameter name or symbol to  be  expanded
+       may  be enclosed in braces, which are optional but serve to protect the
+       variable to be expanded from characters immediately following it  which
+       could be interpreted as part of the name.
+       When  braces  are  used, the matching ending brace is the first `}' not
+       escaped by a backslash or within a quoted string,  and  not  within  an
+       embedded  arithmetic  expansion,  command  substitution,  or  parameter
+       expansion.
+       ${parameter}
+              The value of parameter is substituted.  The braces are  required
+              when  parameter  is  a  positional  parameter with more than one
+              digit, or when parameter is followed by a character which is not
+              to be interpreted as part of its name.
+       If the first character of parameter is an exclamation point, a level of
+       variable indirection is introduced.  Bash uses the value of  the  vari-
+       able  formed  from  the  rest of parameter as the name of the variable;
+       this variable is then expanded and that value is used in  the  rest  of
+       the  substitution,  rather than the value of parameter itself.  This is
+       known as indirect expansion.  The exceptions to this are the expansions
+       of  ${!prefix*} and ${!name[@]} described below.  The exclamation point
+       must immediately follow the left brace in order to  introduce  indirec-
+       tion.
+       In each of the cases below, word is subject to tilde expansion, parame-
+       ter expansion, command substitution, and  arithmetic  expansion.   When
+       not  performing substring expansion, bash tests for a parameter that is
+       unset or null; omitting the colon results in a test only for a  parame-
+       ter that is unset.
+       ${parameter:-word}
+              Use  Default  Values.  If parameter is unset or null, the expan-
+              sion of word is substituted.  Otherwise, the value of  parameter
+              is substituted.
+       ${parameter:=word}
+              Assign  Default  Values.   If  parameter  is  unset or null, the
+              expansion of word is assigned to parameter.  The value of param-
+              eter  is  then  substituted.   Positional parameters and special
+              parameters may not be assigned to in this way.
+       ${parameter:?word}
+              Display Error if Null or Unset.  If parameter is null or  unset,
+              the  expansion  of  word (or a message to that effect if word is
+              not present) is written to the standard error and the shell,  if
+              it is not interactive, exits.  Otherwise, the value of parameter
+              is substituted.
+       ${parameter:+word}
+              Use Alternate Value.  If parameter is null or unset, nothing  is
+              substituted, otherwise the expansion of word is substituted.
+       ${parameter:offset}
+       ${parameter:offset:length}
+              Substring  Expansion.   Expands  to  up  to length characters of
+              parameter starting at the character  specified  by  offset.   If
+              length  is omitted, expands to the substring of parameter start-
+              ing at the character specified by offset.  length and offset are
+              arithmetic   expressions   (see  ARITHMETIC  EVALUATION  below).
+              length must evaluate to a number greater than or equal to  zero.
+              If  offset  evaluates  to  a number less than zero, the value is
+              used as an offset from the end of the value  of  parameter.   If
+              parameter  is  @,  the  result  is  length positional parameters
+              beginning at offset.  If parameter is an array name indexed by @
+              or  *,  the  result is the length members of the array beginning
+              with ${parameter[offset]}.  A negative offset is taken  relative
+              to  one  greater  than the maximum index of the specified array.
+              Note that a negative offset must be separated from the colon  by
+              at  least  one  space to avoid being confused with the :- expan-
+              sion.  Substring indexing is zero-based  unless  the  positional
+              parameters are used, in which case the indexing starts at 1.
+       ${!prefix*}
+       ${!prefix@}
+              Expands to the names of variables whose names begin with prefix,
+              separated by the first character of the IFS special variable.
+       ${!name[@]}
+       ${!name[*]}
+              If name is an array variable,  expands  to  the  list  of  array
+              indices  (keys)  assigned  in  name.   If  name is not an array,
+              expands to 0 if name is set and null otherwise.  When @ is  used
+              and the expansion appears within double quotes, each key expands
+              to a separate word.
+       ${#parameter}
+              The length in characters of the value of  parameter  is  substi-
+              tuted.   If  parameter  is  * or @, the value substituted is the
+              number of positional parameters.  If parameter is an array  name
+              subscripted  by  *  or @, the value substituted is the number of
+              elements in the array.
+       ${parameter#word}
+       ${parameter##word}
+              The word is expanded to produce a pattern just  as  in  pathname
+              expansion.  If the pattern matches the beginning of the value of
+              parameter, then the result of  the  expansion  is  the  expanded
+              value of parameter with the shortest matching pattern (the ``#''
+              case) or the longest matching pattern (the ``##'' case) deleted.
+              If parameter is @ or *, the pattern removal operation is applied
+              to each positional parameter in turn, and the expansion  is  the
+              resultant  list.   If parameter is an array variable subscripted
+              with @ or *, the pattern removal operation is  applied  to  each
+              member  of the array in turn, and the expansion is the resultant
+              list.
+       ${parameter%word}
+       ${parameter%%word}
+              The word is expanded to produce a pattern just  as  in  pathname
+              expansion.   If  the  pattern  matches a trailing portion of the
+              expanded value of parameter, then the result of the expansion is
+              the  expanded value of parameter with the shortest matching pat-
+              tern (the ``%'' case)  or  the  longest  matching  pattern  (the
+              ``%%''  case)  deleted.   If  parameter  is  @ or *, the pattern
+              removal operation is applied to  each  positional  parameter  in
+              turn,  and the expansion is the resultant list.  If parameter is
+              an array variable subscripted with @ or *, the  pattern  removal
+              operation  is  applied  to each member of the array in turn, and
+              the expansion is the resultant list.
+       ${parameter/pattern/string}
+              The pattern is expanded to produce a pattern just as in pathname
+              expansion.   Parameter is expanded and the longest match of pat-
+              tern against its value is replaced  with  string.   If  Ipattern
+              begins  with /, all matches of pattern are replaced with string.
+              Normally only the first match is replaced.   If  pattern  begins
+              with  #, it must match at the beginning of the expanded value of
+              parameter.  If pattern begins with %, it must match at  the  end
+              of  the expanded value of parameter.  If string is null, matches
+              of pattern are deleted and the / following pattern may be  omit-
+              ted.   If  parameter  is  @  or *, the substitution operation is
+              applied to each positional parameter in turn, and the  expansion
+              is  the  resultant list.  If parameter is an array variable sub-
+              scripted with @ or *, the substitution operation is  applied  to
+              each  member  of  the  array  in  turn, and the expansion is the
+              resultant list.
+   Command Substitution
+       Command substitution allows the output of a command to replace the com-
+       mand name.  There are two forms:
+              $(command)
+       or
+              `command`
+       Bash performs the expansion by executing command and replacing the com-
+       mand substitution with the standard output of  the  command,  with  any
+       trailing newlines deleted.  Embedded newlines are not deleted, but they
+       may be removed during word splitting.  The command  substitution  $(cat
+       file) can be replaced by the equivalent but faster $(< file).
+       When  the  old-style  backquote form of substitution is used, backslash
+       retains its literal meaning except when followed by $, `,  or  \.   The
+       first backquote not preceded by a backslash terminates the command sub-
+       stitution.  When using the $(command) form, all characters between  the
+       parentheses make up the command; none are treated specially.
+       Command substitutions may be nested.  To nest when using the backquoted
+       form, escape the inner backquotes with backslashes.
+       If the substitution appears within double quotes,  word  splitting  and
+       pathname expansion are not performed on the results.
+   Arithmetic Expansion
+       Arithmetic  expansion allows the evaluation of an arithmetic expression
+       and the substitution of the result.  The format for  arithmetic  expan-
+       sion is:
+              $((expression))
+       The  expression  is  treated  as if it were within double quotes, but a
+       double quote inside the parentheses  is  not  treated  specially.   All
+       tokens in the expression undergo parameter expansion, string expansion,
+       command substitution, and quote removal.  Arithmetic expansions may  be
+       nested.
+       The  evaluation  is performed according to the rules listed below under
+       ARITHMETIC EVALUATION.  If expression is invalid, bash prints a message
+       indicating failure and no substitution occurs.
+   Process Substitution
+       Process  substitution  is supported on systems that support named pipes
+       (FIFOs) or the /dev/fd method of naming open files.  It takes the  form
+       of  <(list) or >(list).  The process list is run with its input or out-
+       put connected to a FIFO or some file in /dev/fd.  The name of this file
+       is  passed  as  an argument to the current command as the result of the
+       expansion.  If the >(list) form is used, writing to the file will  pro-
+       vide  input  for list.  If the <(list) form is used, the file passed as
+       an argument should be read to obtain the output of list.
+       When available, process substitution is performed  simultaneously  with
+       parameter  and variable expansion, command substitution, and arithmetic
+       expansion.
+   Word Splitting
+       The shell scans the results of parameter expansion,  command  substitu-
+       tion,  and arithmetic expansion that did not occur within double quotes
+       for word splitting.
+       The shell treats each character of IFS as a delimiter, and  splits  the
+       results of the other expansions into words on these characters.  If IFS
+       is unset, or its value is exactly <space><tab><newline>,  the  default,
+       then  any  sequence  of IFS characters serves to delimit words.  If IFS
+       has a value other than the default, then sequences  of  the  whitespace
+       characters  space  and  tab are ignored at the beginning and end of the
+       word, as long as the whitespace character is in the value  of  IFS  (an
+       IFS whitespace character).  Any character in IFS that is not IFS white-
+       space, along with any adjacent IFS whitespace  characters,  delimits  a
+       field.   A  sequence  of IFS whitespace characters is also treated as a
+       delimiter.  If the value of IFS is null, no word splitting occurs.
+       Explicit null arguments ("" or '')  are  retained.   Unquoted  implicit
+       null arguments, resulting from the expansion of parameters that have no
+       values, are removed.  If a parameter with no value is  expanded  within
+       double quotes, a null argument results and is retained.
+       Note that if no expansion occurs, no splitting is performed.
+   Pathname Expansion
+       After  word  splitting,  unless  the -f option has been set, bash scans
+       each word for the characters *, ?, and [.  If one of  these  characters
+       appears,  then  the word is regarded as a pattern, and replaced with an
+       alphabetically sorted list of file names matching the pattern.   If  no
+       matching  file  names  are found, and the shell option nullglob is dis-
+       abled, the word is left unchanged.  If the nullglob option is set,  and
+       no  matches  are  found,  the  word  is removed.  If the failglob shell
+       option is set, and no matches are found, an error  message  is  printed
+       and  the  command  is  not executed.  If the shell option nocaseglob is
+       enabled, the match is performed without regard to the  case  of  alpha-
+       betic  characters.   When a pattern is used for pathname expansion, the
+       character ``.''  at the start of a  name  or  immediately  following  a
+       slash  must  be  matched explicitly, unless the shell option dotglob is
+       set.  When matching a pathname, the  slash  character  must  always  be
+       matched  explicitly.   In  other  cases,  the  ``.''   character is not
+       treated specially.  See the description  of  shopt  below  under  SHELL
+       BUILTIN  COMMANDS  for a description of the nocaseglob, nullglob, fail-
+       glob, and dotglob shell options.
+       The GLOBIGNORE shell variable may be used to restrict the set  of  file
+       names  matching  a  pattern.   If GLOBIGNORE is set, each matching file
+       name that also matches one of the patterns  in  GLOBIGNORE  is  removed
+       from the list of matches.  The file names ``.''  and ``..''  are always
+       ignored when GLOBIGNORE is set and not null.  However, setting  GLOBIG-
+       NORE  to  a non-null value has the effect of enabling the dotglob shell
+       option, so all other file names beginning with a ``.''  will match.  To
+       get  the  old  behavior  of ignoring file names beginning with a ``.'',
+       make ``.*''  one of the patterns in GLOBIGNORE.  The dotglob option  is
+       disabled when GLOBIGNORE is unset.
+       Pattern Matching
+       Any character that appears in a pattern, other than the special pattern
+       characters described below, matches itself.  The NUL character may  not
+       occur  in  a pattern.  A backslash escapes the following character; the
+       escaping backslash is discarded when  matching.   The  special  pattern
+       characters must be quoted if they are to be matched literally.
+       The special pattern characters have the following meanings:
+       *      Matches any string, including the null string.
+       ?      Matches any single character.
+       [...]  Matches  any  one of the enclosed characters.  A pair of charac-
+              ters separated by a hyphen denotes a range expression; any char-
+              acter  that sorts between those two characters, inclusive, using
+              the current locale's collating sequence and  character  set,  is
+              matched.   If the first character following the [ is a !  or a ^
+              then any character not enclosed is matched.  The  sorting  order
+              of  characters in range expressions is determined by the current
+              locale and the value of the LC_COLLATE shell variable,  if  set.
+              A  - may be matched by including it as the first or last charac-
+              ter in the set.  A ] may be matched by including it as the first
+              character in the set.
+              Within  [  and  ],  character classes can be specified using the
+              syntax [:class:], where class is one of  the  following  classes
+              defined in the POSIX standard:
+              alnum  alpha  ascii  blank  cntrl  digit graph lower print punct
+              space upper word xdigit
+              A character class matches any character belonging to that class.
+              The  word character class matches letters, digits, and the char-
+              acter _.
+              Within [ and ], an equivalence class can be specified using  the
+              syntax  [=c=], which matches all characters with the same colla-
+              tion weight (as defined by the current locale) as the  character
+              c.
+              Within [ and ], the syntax [.symbol.] matches the collating sym-
+              bol symbol.
+       If the extglob shell option is enabled using the shopt builtin, several
+       extended  pattern  matching operators are recognized.  In the following
+       description, a pattern-list is a list of one or more patterns separated
+       by a |.  Composite patterns may be formed using one or more of the fol-
+       lowing sub-patterns:
+              ?(pattern-list)
+                     Matches zero or one occurrence of the given patterns
+              *(pattern-list)
+                     Matches zero or more occurrences of the given patterns
+              +(pattern-list)
+                     Matches one or more occurrences of the given patterns
+              @(pattern-list)
+                     Matches one of the given patterns
+              !(pattern-list)
+                     Matches anything except one of the given patterns
+   Quote Removal
+       After the preceding expansions, all unquoted occurrences of the charac-
+       ters  \,  ', and " that did not result from one of the above expansions
+       are removed.
+REDIRECTION
+       Before a command is executed, its input and output  may  be  redirected
+       using  a  special  notation  interpreted by the shell.  Redirection may
+       also be used to open and close files for the  current  shell  execution
+       environment.  The following redirection operators may precede or appear
+       anywhere within a simple command or may follow a command.  Redirections
+       are processed in the order they appear, from left to right.
+       In  the  following descriptions, if the file descriptor number is omit-
+       ted, and the first character of the redirection operator is <, the  re-
+       direction  refers  to  the  standard input (file descriptor 0).  If the
+       first character of the  redirection  operator  is  >,  the  redirection
+       refers to the standard output (file descriptor 1).
+       The  word  following the redirection operator in the following descrip-
+       tions, unless otherwise noted, is subjected to brace  expansion,  tilde
+       expansion, parameter expansion, command substitution, arithmetic expan-
+       sion, quote removal, pathname expansion, and  word  splitting.   If  it
+       expands to more than one word, bash reports an error.
+       Note  that  the order of redirections is significant.  For example, the
+       command
+              ls > dirlist 2>&1
+       directs both standard output and standard error to  the  file  dirlist,
+       while the command
+              ls 2>&1 > dirlist
+       directs  only the standard output to file dirlist, because the standard
+       error was duplicated as standard output before the standard output  was
+       redirected to dirlist.
+       Bash handles several filenames specially when they are used in redirec-
+       tions, as described in the following table:
+              /dev/fd/fd
+                     If fd is a valid integer, file descriptor  fd  is  dupli-
+                     cated.
+              /dev/stdin
+                     File descriptor 0 is duplicated.
+              /dev/stdout
+                     File descriptor 1 is duplicated.
+              /dev/stderr
+                     File descriptor 2 is duplicated.
+              /dev/tcp/host/port
+                     If host is a valid hostname or Internet address, and port
+                     is an integer port number or service name, bash  attempts
+                     to open a TCP connection to the corresponding socket.
+              /dev/udp/host/port
+                     If host is a valid hostname or Internet address, and port
+                     is an integer port number or service name, bash  attempts
+                     to open a UDP connection to the corresponding socket.
+       A failure to open or create a file causes the redirection to fail.
+       Redirections  using file descriptors greater than 9 should be used with
+       care, as they may conflict with file descriptors the shell uses  inter-
+       nally.
+   Redirecting Input
+       Redirection of input causes the file whose name results from the expan-
+       sion of word to be opened for reading on  file  descriptor  n,  or  the
+       standard input (file descriptor 0) if n is not specified.
+       The general format for redirecting input is:
+              [n]<word
+   Redirecting Output
+       Redirection  of  output  causes  the  file  whose name results from the
+       expansion of word to be opened for writing on file descriptor n, or the
+       standard output (file descriptor 1) if n is not specified.  If the file
+       does not exist it is created; if it does exist it is truncated to  zero
+       size.
+       The general format for redirecting output is:
+              [n]>word
+       If  the  redirection operator is >, and the noclobber option to the set
+       builtin has been enabled, the redirection will fail if the  file  whose
+       name  results  from the expansion of word exists and is a regular file.
+       If the redirection operator is >|, or the redirection operator is > and
+       the noclobber option to the set builtin command is not enabled, the re-
+       direction is attempted even if the file named by word exists.
+   Appending Redirected Output
+       Redirection of output in  this  fashion  causes  the  file  whose  name
+       results  from  the expansion of word to be opened for appending on file
+       descriptor n, or the standard output (file descriptor 1) if  n  is  not
+       specified.  If the file does not exist it is created.
+       The general format for appending output is:
+              [n]>>word
+   Redirecting Standard Output and Standard Error
+       Bash  allows both the standard output (file descriptor 1) and the stan-
+       dard error output (file descriptor 2) to  be  redirected  to  the  file
+       whose name is the expansion of word with this construct.
+       There  are  two  formats  for  redirecting standard output and standard
+       error:
+              &>word
+       and
+              >&word
+       Of the two forms, the first is preferred.  This is semantically equiva-
+       lent to
+              >word 2>&1
+   Here Documents
+       This  type  of  redirection  instructs the shell to read input from the
+       current source until a line containing  only  word  (with  no  trailing
+       blanks)  is seen.  All of the lines read up to that point are then used
+       as the standard input for a command.
+       The format of here-documents is:
+              <<[-]word
+                      here-document
+              delimiter
+       No parameter expansion, command substitution, arithmetic expansion,  or
+       pathname expansion is performed on word.  If any characters in word are
+       quoted, the delimiter is the result of quote removal on word,  and  the
+       lines  in the here-document are not expanded.  If word is unquoted, all
+       lines of the here-document are subjected to parameter  expansion,  com-
+       mand  substitution,  and arithmetic expansion.  In the latter case, the
+       character sequence \<newline> is ignored, and \ must be used  to  quote
+       the characters \, $, and `.
+       If the redirection operator is <<-, then all leading tab characters are
+       stripped from input lines and  the  line  containing  delimiter.   This
+       allows  here-documents within shell scripts to be indented in a natural
+       fashion.
+   Here Strings
+       A variant of here documents, the format is:
+              <<<word
+       The word is expanded and supplied to the command on its standard input.
+   Duplicating File Descriptors
+       The redirection operator
+              [n]<&word
+       is used to duplicate input file descriptors.  If word expands to one or
+       more digits, the file descriptor denoted by n is made to be a  copy  of
+       that  file  descriptor.   If  the  digits in word do not specify a file
+       descriptor open for input, a redirection error occurs.  If word  evalu-
+       ates  to  -,  file  descriptor n is closed.  If n is not specified, the
+       standard input (file descriptor 0) is used.
+       The operator
+              [n]>&word
+       is used similarly to duplicate output file descriptors.  If  n  is  not
+       specified,  the  standard  output  (file descriptor 1) is used.  If the
+       digits in word do not specify a file descriptor open for output, a  re-
+       direction  error  occurs.  As a special case, if n is omitted, and word
+       does not expand to one or more digits, the standard output and standard
+       error are redirected as described previously.
+   Moving File Descriptors
+       The redirection operator
+              [n]<&digit-
+       moves  the  file descriptor digit to file descriptor n, or the standard
+       input (file descriptor 0) if n is not specified.  digit is closed after
+       being duplicated to n.
+       Similarly, the redirection operator
+              [n]>&digit-
+       moves  the  file descriptor digit to file descriptor n, or the standard
+       output (file descriptor 1) if n is not specified.
+   Opening File Descriptors for Reading and Writing
+       The redirection operator
+              [n]<>word
+       causes the file whose name is the expansion of word to  be  opened  for
+       both  reading and writing on file descriptor n, or on file descriptor 0
+       if n is not specified.  If the file does not exist, it is created.
+ALIASES
+       Aliases allow a string to be substituted for a word when it is used  as
+       the  first  word  of  a  simple command.  The shell maintains a list of
+       aliases that may be set and unset with the alias  and  unalias  builtin
+       commands  (see  SHELL  BUILTIN COMMANDS below).  The first word of each
+       simple command, if unquoted, is checked to see if it has an alias.   If
+       so,  that word is replaced by the text of the alias.  The characters /,
+       $, `, and = and any of the shell metacharacters or  quoting  characters
+       listed above may not appear in an alias name.  The replacement text may
+       contain any valid shell input,  including  shell  metacharacters.   The
+       first  word  of  the replacement text is tested for aliases, but a word
+       that is identical to an alias being expanded is not expanded  a  second
+       time.   This  means  that  one may alias ls to ls -F, for instance, and
+       bash does not try to recursively expand the replacement text.   If  the
+       last  character  of  the  alias value is a blank, then the next command
+       word following the alias is also checked for alias expansion.
+       Aliases are created and listed with the alias command, and removed with
+       the unalias command.
+       There  is no mechanism for using arguments in the replacement text.  If
+       arguments are needed, a shell function should be  used  (see  FUNCTIONS
+       below).
+       Aliases  are not expanded when the shell is not interactive, unless the
+       expand_aliases shell option is set using shopt (see the description  of
+       shopt under SHELL BUILTIN COMMANDS below).
+       The  rules  concerning  the  definition and use of aliases are somewhat
+       confusing.  Bash always reads at  least  one  complete  line  of  input
+       before  executing  any  of  the  commands  on  that  line.  Aliases are
+       expanded when a command is read, not when it is  executed.   Therefore,
+       an  alias definition appearing on the same line as another command does
+       not take effect until the next line of input  is  read.   The  commands
+       following the alias definition on that line are not affected by the new
+       alias.  This behavior is also an issue  when  functions  are  executed.
+       Aliases  are  expanded when a function definition is read, not when the
+       function is executed, because a function definition is  itself  a  com-
+       pound command.  As a consequence, aliases defined in a function are not
+       available until after that function is executed.  To  be  safe,  always
+       put  alias definitions on a separate line, and do not use alias in com-
+       pound commands.
+       For almost every purpose, aliases are superseded by shell functions.
+FUNCTIONS
+       A shell function, defined  as  described  above  under  SHELL  GRAMMAR,
+       stores  a  series  of commands for later execution.  When the name of a
+       shell function is used as a simple command name, the list  of  commands
+       associated with that function name is executed.  Functions are executed
+       in the context of the current shell;  no  new  process  is  created  to
+       interpret  them  (contrast  this with the execution of a shell script).
+       When a function is executed, the arguments to the function  become  the
+       positional parameters during its execution.  The special parameter # is
+       updated to reflect the change.  Special parameter 0 is unchanged.   The
+       first  element of the FUNCNAME variable is set to the name of the func-
+       tion while the function is executing.  All other aspects of  the  shell
+       execution  environment  are identical between a function and its caller
+       with the exception that the DEBUG and RETURN traps (see the description
+       of  the trap builtin under SHELL BUILTIN COMMANDS below) are not inher-
+       ited unless the function has been given the trace  attribute  (see  the
+       description  of  the  declare  builtin below) or the -o functrace shell
+       option has been enabled with the set builtin (in which case  all  func-
+       tions inherit the DEBUG and RETURN traps).
+       Variables  local to the function may be declared with the local builtin
+       command.  Ordinarily, variables and their values are shared between the
+       function and its caller.
+       If  the  builtin command return is executed in a function, the function
+       completes and execution resumes with the next command after  the  func-
+       tion  call.   Any  command  associated with the RETURN trap is executed
+       before execution resumes.  When a function completes, the values of the
+       positional  parameters  and the special parameter # are restored to the
+       values they had prior to the function's execution.
+       Function names and definitions may be listed with the -f option to  the
+       declare or typeset builtin commands.  The -F option to declare or type-
+       set will list the function names only (and optionally the  source  file
+       and  line  number, if the extdebug shell option is enabled).  Functions
+       may be exported so that subshells automatically have them defined  with
+       the  -f  option  to  the  export builtin.  A function definition may be
+       deleted using the -f option to the  unset  builtin.   Note  that  shell
+       functions and variables with the same name may result in multiple iden-
+       tically-named entries in the environment passed to  the  shell's  chil-
+       dren.  Care should be taken in cases where this may cause a problem.
+       Functions  may  be  recursive.   No  limit  is imposed on the number of
+       recursive calls.
+ARITHMETIC EVALUATION
+       The shell allows arithmetic expressions to be evaluated, under  certain
+       circumstances  (see the let and declare builtin commands and Arithmetic
+       Expansion).  Evaluation is done in fixed-width integers with  no  check
+       for  overflow, though division by 0 is trapped and flagged as an error.
+       The operators and their precedence, associativity, and values  are  the
+       same  as in the C language.  The following list of operators is grouped
+       into levels of equal-precedence operators.  The levels  are  listed  in
+       order of decreasing precedence.
+       id++ id--
+              variable post-increment and post-decrement
+       ++id --id
+              variable pre-increment and pre-decrement
+       - +    unary minus and plus
+       ! ~    logical and bitwise negation
+       **     exponentiation
+       * / %  multiplication, division, remainder
+       + -    addition, subtraction
+       << >>  left and right bitwise shifts
+       <= >= < >
+              comparison
+       == !=  equality and inequality
+       &      bitwise AND
+       ^      bitwise exclusive OR
+       |      bitwise OR
+       &&     logical AND
+       ||     logical OR
+       expr?expr:expr
+              conditional operator
+       = *= /= %= += -= <<= >>= &= ^= |=
+              assignment
+       expr1 , expr2
+              comma
+       Shell  variables  are  allowed as operands; parameter expansion is per-
+       formed before the expression is evaluated.  Within an expression, shell
+       variables  may  also  be referenced by name without using the parameter
+       expansion syntax.  A shell variable that is null or unset evaluates  to
+when referenced by name without using the parameter expansion syntax.
+       The value of a variable is evaluated as an arithmetic  expression  when
+       it  is  referenced, or when a variable which has been given the integer
+       attribute using declare -i is assigned a value.  A null value evaluates
+       to  0.   A shell variable need not have its integer attribute turned on
+       to be used in an expression.
+       Constants with a leading 0 are interpreted as octal numbers.  A leading
+x  or  0X  denotes  hexadecimal.   Otherwise,  numbers  take  the form
+       [base#]n, where base is a decimal number between 2 and 64  representing
+       the arithmetic base, and n is a number in that base.  If base# is omit-
+       ted, then base 10 is used.  The digits greater than 9  are  represented
+       by  the  lowercase  letters,  the  uppercase letters, @, and _, in that
+       order.  If base is less than or equal to 36,  lowercase  and  uppercase
+       letters may be used interchangeably to represent numbers between 10 and
+.
+       Operators are evaluated in order  of  precedence.   Sub-expressions  in
+       parentheses  are  evaluated first and may override the precedence rules
+       above.
+CONDITIONAL EXPRESSIONS
+       Conditional expressions are used by the [[  compound  command  and  the
+       test  and [ builtin commands to test file attributes and perform string
+       and arithmetic comparisons.  Expressions are formed from the  following
+       unary  or  binary  primaries.   If any file argument to one of the pri-
+       maries is of the form /dev/fd/n, then file descriptor n is checked.  If
+       the  file  argument  to  one  of  the  primaries  is one of /dev/stdin,
+       /dev/stdout, or /dev/stderr, file descriptor 0, 1, or 2,  respectively,
+       is checked.
+       Unless otherwise specified, primaries that operate on files follow sym-
+       bolic links and operate on the target of the link, rather than the link
+       itself.
+       -a file
+              True if file exists.
+       -b file
+              True if file exists and is a block special file.
+       -c file
+              True if file exists and is a character special file.
+       -d file
+              True if file exists and is a directory.
+       -e file
+              True if file exists.
+       -f file
+              True if file exists and is a regular file.
+       -g file
+              True if file exists and is set-group-id.
+       -h file
+              True if file exists and is a symbolic link.
+       -k file
+              True if file exists and its ``sticky'' bit is set.
+       -p file
+              True if file exists and is a named pipe (FIFO).
+       -r file
+              True if file exists and is readable.
+       -s file
+              True if file exists and has a size greater than zero.
+       -t fd  True if file descriptor fd is open and refers to a terminal.
+       -u file
+              True if file exists and its set-user-id bit is set.
+       -w file
+              True if file exists and is writable.
+       -x file
+              True if file exists and is executable.
+       -O file
+              True if file exists and is owned by the effective user id.
+       -G file
+              True if file exists and is owned by the effective group id.
+       -L file
+              True if file exists and is a symbolic link.
+       -S file
+              True if file exists and is a socket.
+       -N file
+              True  if  file  exists  and  has been modified since it was last
+              read.
+       file1 -nt file2
+              True if file1 is newer (according  to  modification  date)  than
+              file2, or if file1 exists and file2 does not.
+       file1 -ot file2
+              True  if file1 is older than file2, or if file2 exists and file1
+              does not.
+       file1 -ef file2
+              True if file1 and file2 refer to the same device and inode  num-
+              bers.
+       -o optname
+              True  if  shell  option  optname  is  enabled.   See the list of
+              options under the description  of  the  -o  option  to  the  set
+              builtin below.
+       -z string
+              True if the length of string is zero.
+       string
+       -n string
+              True if the length of string is non-zero.
+       string1 == string2
+              True if the strings are equal.  = may be used in place of == for
+              strict POSIX compliance.
+       string1 != string2
+              True if the strings are not equal.
+       string1 < string2
+              True if string1 sorts before string2  lexicographically  in  the
+              current locale.
+       string1 > string2
+              True  if  string1  sorts  after string2 lexicographically in the
+              current locale.
+       arg1 OP arg2
+              OP is one of -eq, -ne, -lt, -le, -gt, or -ge.  These  arithmetic
+              binary  operators return true if arg1 is equal to, not equal to,
+              less than, less than or equal to, greater than, or greater  than
+              or  equal  to arg2, respectively.  Arg1 and arg2 may be positive
+              or negative integers.
+SIMPLE COMMAND EXPANSION
+       When a simple command is executed, the  shell  performs  the  following
+       expansions, assignments, and redirections, from left to right.
+.     The  words  that  the  parser has marked as variable assignments
+              (those preceding the command name) and  redirections  are  saved
+              for later processing.
+.     The  words that are not variable assignments or redirections are
+              expanded.  If any words remain after expansion, the  first  word
+              is  taken  to be the name of the command and the remaining words
+              are the arguments.
+.     Redirections are performed as described above under REDIRECTION.
+.     The text after the = in each variable assignment undergoes tilde
+              expansion, parameter expansion, command substitution, arithmetic
+              expansion,  and quote removal before being assigned to the vari-
+              able.
+       If no command name results, the variable assignments affect the current
+       shell  environment.  Otherwise, the variables are added to the environ-
+       ment of the executed command and do not affect the current shell  envi-
+       ronment.   If  any  of  the assignments attempts to assign a value to a
+       readonly variable, an error occurs, and the command exits with  a  non-
+       zero status.
+       If  no  command  name  results,  redirections are performed, but do not
+       affect the current shell environment.  A redirection error  causes  the
+       command to exit with a non-zero status.
+       If  there is a command name left after expansion, execution proceeds as
+       described below.  Otherwise, the command exits.  If one of  the  expan-
+       sions  contained a command substitution, the exit status of the command
+       is the exit status of the  last  command  substitution  performed.   If
+       there were no command substitutions, the command exits with a status of
+       zero.
+COMMAND EXECUTION
+       After a command has been split into words, if it results  in  a  simple
+       command  and  an  optional list of arguments, the following actions are
+       taken.
+       If the command name contains no slashes, the shell attempts  to  locate
+       it.   If  there  exists a shell function by that name, that function is
+       invoked as described above in FUNCTIONS.  If the name does not match  a
+       function,  the shell searches for it in the list of shell builtins.  If
+       a match is found, that builtin is invoked.
+       If the name is neither a shell function nor a builtin, and contains  no
+       slashes,  bash  searches  each element of the PATH for a directory con-
+       taining an executable file by that name.  Bash uses  a  hash  table  to
+       remember  the  full pathnames of executable files (see hash under SHELL
+       BUILTIN COMMANDS below).  A full search of the directories in  PATH  is
+       performed  only  if the command is not found in the hash table.  If the
+       search is unsuccessful, the shell prints an error message  and  returns
+       an exit status of 127.
+       If  the  search  is  successful, or if the command name contains one or
+       more slashes, the shell executes the named program in a separate execu-
+       tion environment.  Argument 0 is set to the name given, and the remain-
+       ing arguments to the command are set to the arguments given, if any.
+       If this execution fails because the file is not in  executable  format,
+       and  the file is not a directory, it is assumed to be a shell script, a
+       file containing shell commands.  A subshell is spawned to  execute  it.
+       This  subshell  reinitializes itself, so that the effect is as if a new
+       shell had been invoked to handle the script, with  the  exception  that
+       the  locations  of  commands  remembered  by the parent (see hash below
+       under SHELL BUILTIN COMMANDS) are retained by the child.
+       If the program is a file beginning with #!, the remainder of the  first
+       line  specifies an interpreter for the program.  The shell executes the
+       specified interpreter on operating systems that do not handle this exe-
+       cutable format themselves.  The arguments to the interpreter consist of
+       a single optional argument following the interpreter name on the  first
+       line  of  the program, followed by the name of the program, followed by
+       the command arguments, if any.
+COMMAND EXECUTION ENVIRONMENT
+       The shell has an execution environment, which consists of  the  follow-
+       ing:
+       o      open  files inherited by the shell at invocation, as modified by
+              redirections supplied to the exec builtin
+       o      the current working directory as set by cd, pushd, or  popd,  or
+              inherited by the shell at invocation
+       o      the  file  creation  mode mask as set by umask or inherited from
+              the shell's parent
+       o      current traps set by trap
+       o      shell parameters that are set by variable assignment or with set
+              or inherited from the shell's parent in the environment
+       o      shell  functions  defined during execution or inherited from the
+              shell's parent in the environment
+       o      options enabled at invocation (either by default  or  with  com-
+              mand-line arguments) or by set
+       o      options enabled by shopt
+       o      shell aliases defined with alias
+       o      various  process  IDs,  including  those of background jobs, the
+              value of $$, and the value of $PPID
+       When a simple command other than a builtin or shell function is  to  be
+       executed,  it  is invoked in a separate execution environment that con-
+       sists of the following.  Unless otherwise noted, the values are  inher-
+       ited from the shell.
+       o      the  shell's  open  files,  plus any modifications and additions
+              specified by redirections to the command
+       o      the current working directory
+       o      the file creation mode mask
+       o      shell variables and functions  marked  for  export,  along  with
+              variables exported for the command, passed in the environment
+       o      traps caught by the shell are reset to the values inherited from
+              the shell's parent, and traps ignored by the shell are ignored
+       A command invoked  in  this  separate  environment  cannot  affect  the
+       shell's execution environment.
+       Command  substitution, commands grouped with parentheses, and asynchro-
+       nous commands are invoked in a subshell environment that is a duplicate
+       of  the  shell  environment,  except that traps caught by the shell are
+       reset to the values that the shell inherited from its parent at invoca-
+       tion.  Builtin commands that are invoked as part of a pipeline are also
+       executed in a subshell environment.  Changes made to the subshell envi-
+       ronment cannot affect the shell's execution environment.
+       If  a  command  is  followed  by a & and job control is not active, the
+       default standard input for the command is  the  empty  file  /dev/null.
+       Otherwise,  the  invoked  command  inherits the file descriptors of the
+       calling shell as modified by redirections.
+ENVIRONMENT
+       When a program is invoked it is given an array of  strings  called  the
+       environment.   This  is  a  list  of  name-value  pairs,  of  the  form
+       name=value.
+       The shell provides several ways  to  manipulate  the  environment.   On
+       invocation, the shell scans its own environment and creates a parameter
+       for each name found, automatically marking it for export to child  pro-
+       cesses.   Executed  commands  inherit  the environment.  The export and
+       declare -x commands allow parameters and functions to be added  to  and
+       deleted from the environment.  If the value of a parameter in the envi-
+       ronment is modified, the new value becomes  part  of  the  environment,
+       replacing  the  old.  The environment inherited by any executed command
+       consists of the shell's initial environment, whose values may be  modi-
+       fied  in  the  shell, less any pairs removed by the unset command, plus
+       any additions via the export and declare -x commands.
+       The environment for any simple command or  function  may  be  augmented
+       temporarily  by  prefixing  it with parameter assignments, as described
+       above in PARAMETERS.  These assignment statements affect only the envi-
+       ronment seen by that command.
+       If  the  -k option is set (see the set builtin command below), then all
+       parameter assignments are placed in the environment for a command,  not
+       just those that precede the command name.
+       When  bash  invokes  an  external command, the variable _ is set to the
+       full file name of the command and passed to that command in  its  envi-
+       ronment.
+EXIT STATUS
+       For the shell's purposes, a command which exits with a zero exit status
+       has succeeded.  An exit status of zero indicates success.   A  non-zero
+       exit  status  indicates  failure.  When a command terminates on a fatal
+       signal N, bash uses the value of 128+N as the exit status.
+       If a command is not found, the child  process  created  to  execute  it
+       returns  a status of 127.  If a command is found but is not executable,
+       the return status is 126.
+       If a command fails because of an error during expansion or redirection,
+       the exit status is greater than zero.
+       Shell  builtin  commands return a status of 0 (true) if successful, and
+       non-zero (false) if an error occurs while they execute.   All  builtins
+       return an exit status of 2 to indicate incorrect usage.
+       Bash  itself  returns  the  exit  status  of the last command executed,
+       unless a syntax error occurs, in which case it exits  with  a  non-zero
+       value.  See also the exit builtin command below.
+SIGNALS
+       When  bash  is  interactive,  in  the  absence of any traps, it ignores
+       SIGTERM (so that kill 0 does not kill an interactive shell), and SIGINT
+       is  caught and handled (so that the wait builtin is interruptible).  In
+       all cases, bash ignores SIGQUIT.  If job control  is  in  effect,  bash
+       ignores SIGTTIN, SIGTTOU, and SIGTSTP.
+       Non-builtin commands run by bash have signal handlers set to the values
+       inherited by the shell from its parent.  When job  control  is  not  in
+       effect,  asynchronous commands ignore SIGINT and SIGQUIT in addition to
+       these inherited handlers.  Commands run as a result of command  substi-
+       tution ignore the keyboard-generated job control signals SIGTTIN, SIGT-
+       TOU, and SIGTSTP.
+       The shell exits by default upon receipt of a SIGHUP.   Before  exiting,
+       an  interactive  shell  resends  the  SIGHUP  to  all  jobs, running or
+       stopped.  Stopped jobs are sent SIGCONT to ensure that they receive the
+       SIGHUP.   To  prevent the shell from sending the signal to a particular
+       job, it should be removed from the jobs table with the  disown  builtin
+       (see  SHELL  BUILTIN  COMMANDS  below)  or marked to not receive SIGHUP
+       using disown -h.
+       If the huponexit shell option has been set with  shopt,  bash  sends  a
+       SIGHUP to all jobs when an interactive login shell exits.
+       If  bash is waiting for a command to complete and receives a signal for
+       which a trap has been set, the trap will not be executed until the com-
+       mand  completes.   When bash is waiting for an asynchronous command via
+       the wait builtin, the reception of a signal for which a trap  has  been
+       set will cause the wait builtin to return immediately with an exit sta-
+       tus greater than 128, immediately after which the trap is executed.
+JOB CONTROL
+       Job control refers to the ability to  selectively  stop  (suspend)  the
+       execution of processes and continue (resume) their execution at a later
+       point.  A user typically  employs  this  facility  via  an  interactive
+       interface supplied jointly by the system's terminal driver and bash.
+       The  shell  associates  a  job with each pipeline.  It keeps a table of
+       currently executing jobs, which may be listed with  the  jobs  command.
+       When  bash starts a job asynchronously (in the background), it prints a
+       line that looks like:
+              [1] 25647
+       indicating that this job is job number 1 and that the process ID of the
+       last process in the pipeline associated with this job is 25647.  All of
+       the processes in a single pipeline are members of the same  job.   Bash
+       uses the job abstraction as the basis for job control.
+       To  facilitate the implementation of the user interface to job control,
+       the operating system maintains the notion of a current terminal process
+       group ID.  Members of this process group (processes whose process group
+       ID is equal to the current terminal process group ID) receive keyboard-
+       generated  signals  such  as SIGINT.  These processes are said to be in
+       the foreground.  Background processes are those whose process group  ID
+       differs from the terminal's; such processes are immune to keyboard-gen-
+       erated signals.  Only foreground processes are allowed to read from  or
+       write to the terminal.  Background processes which attempt to read from
+       (write to) the terminal are sent a SIGTTIN (SIGTTOU) signal by the ter-
+       minal driver, which, unless caught, suspends the process.
+       If  the operating system on which bash is running supports job control,
+       bash contains facilities to use it.  Typing the suspend character (typ-
+       ically ^Z, Control-Z) while a process is running causes that process to
+       be stopped and returns control to bash.   Typing  the  delayed  suspend
+       character  (typically  ^Y,  Control-Y) causes the process to be stopped
+       when it attempts to read input from the terminal,  and  control  to  be
+       returned  to bash.  The user may then manipulate the state of this job,
+       using the bg command to continue it in the background, the  fg  command
+       to continue it in the foreground, or the kill command to kill it.  A ^Z
+       takes effect immediately, and has the additional side effect of causing
+       pending output and typeahead to be discarded.
+       There are a number of ways to refer to a job in the shell.  The charac-
+       ter % introduces a job name.  Job number n may be referred to as %n.  A
+       job  may  also  be referred to using a prefix of the name used to start
+       it, or using a substring that appears in its command line.   For  exam-
+       ple, %ce refers to a stopped ce job.  If a prefix matches more than one
+       job, bash reports an error.  Using %?ce, on the other hand,  refers  to
+       any job containing the string ce in its command line.  If the substring
+       matches more than one job, bash reports an error.  The symbols  %%  and
+       %+  refer  to  the shell's notion of the current job, which is the last
+       job stopped while it was in the foreground  or  started  in  the  back-
+       ground.   The  previous job may be referenced using %-.  In output per-
+       taining to jobs (e.g., the output of the jobs command), the current job
+       is  always flagged with a +, and the previous job with a -.  A single %
+       (with no accompanying job specification) also  refers  to  the  current
+       job.
+       Simply  naming a job can be used to bring it into the foreground: %1 is
+       a synonym for ``fg %1'', bringing job 1 from the  background  into  the
+       foreground.   Similarly,  ``%1  &''  resumes  job  1 in the background,
+       equivalent to ``bg %1''.
+       The shell learns immediately whenever a job changes  state.   Normally,
+       bash waits until it is about to print a prompt before reporting changes
+       in a job's status so as to not interrupt any other output.  If  the  -b
+       option to the set builtin command is enabled, bash reports such changes
+       immediately.  Any trap on SIGCHLD  is  executed  for  each  child  that
+       exits.
+       If  an  attempt  to exit bash is made while jobs are stopped, the shell
+       prints a warning message.  The jobs command may then be used to inspect
+       their status.  If a second attempt to exit is made without an interven-
+       ing command, the shell does not print another warning, and the  stopped
+       jobs are terminated.
+PROMPTING
+       When executing interactively, bash displays the primary prompt PS1 when
+       it is ready to read a command, and the secondary  prompt  PS2  when  it
+       needs  more  input  to  complete  a  command.  Bash allows these prompt
+       strings to be customized by inserting  a  number  of  backslash-escaped
+       special characters that are decoded as follows:
+              \a     an ASCII bell character (07)
+              \d     the  date  in "Weekday Month Date" format (e.g., "Tue May
+")
+              \D{format}
+                     the format is passed to strftime(3)  and  the  result  is
+                     inserted  into the prompt string; an empty format results
+                     in a locale-specific time representation.  The braces are
+                     required
+              \e     an ASCII escape character (033)
+              \h     the hostname up to the first `.'
+              \H     the hostname
+              \j     the number of jobs currently managed by the shell
+              \l     the basename of the shell's terminal device name
+              \n     newline
+              \r     carriage return
+              \s     the  name  of  the shell, the basename of $0 (the portion
+                     following the final slash)
+              \t     the current time in 24-hour HH:MM:SS format
+              \T     the current time in 12-hour HH:MM:SS format
+              \@     the current time in 12-hour am/pm format
+              \A     the current time in 24-hour HH:MM format
+              \u     the username of the current user
+              \v     the version of bash (e.g., 2.00)
+              \V     the release of bash, version + patch level (e.g., 2.00.0)
+              \w     the  current  working  directory,  with $HOME abbreviated
+                     with a tilde
+              \W     the basename of the current working directory, with $HOME
+                     abbreviated with a tilde
+              \!     the history number of this command
+              \#     the command number of this command
+              \$     if the effective UID is 0, a #, otherwise a $
+              \nnn   the character corresponding to the octal number nnn
+              \\     a backslash
+              \[     begin  a sequence of non-printing characters, which could
+                     be used to embed a terminal  control  sequence  into  the
+                     prompt
+              \]     end a sequence of non-printing characters
+       The  command  number  and the history number are usually different: the
+       history number of a command is its position in the history list,  which
+       may  include  commands  restored  from  the  history  file (see HISTORY
+       below), while the command number is the position  in  the  sequence  of
+       commands  executed  during the current shell session.  After the string
+       is decoded, it is expanded via parameter expansion,  command  substitu-
+       tion,  arithmetic expansion, and quote removal, subject to the value of
+       the promptvars shell option (see the description of the  shopt  command
+       under SHELL BUILTIN COMMANDS below).
+READLINE
+       This  is  the library that handles reading input when using an interac-
+       tive shell, unless the --noediting option is given at shell invocation.
+       By default, the line editing commands are similar to those of emacs.  A
+       vi-style line editing interface is also available.  To  turn  off  line
+       editing  after  the shell is running, use the +o emacs or +o vi options
+       to the set builtin (see SHELL BUILTIN COMMANDS below).
+   Readline Notation
+       In this section, the emacs-style notation is used to denote keystrokes.
+       Control  keys  are  denoted by C-key, e.g., C-n means Control-N.  Simi-
+       larly, meta keys are denoted by M-key, so M-x means Meta-X.   (On  key-
+       boards  without a meta key, M-x means ESC x, i.e., press the Escape key
+       then the x key.  This makes ESC the meta prefix.  The combination M-C-x
+       means  ESC-Control-x, or press the Escape key then hold the Control key
+       while pressing the x key.)
+       Readline commands may be given numeric arguments, which normally act as
+       a  repeat  count.   Sometimes,  however, it is the sign of the argument
+       that is significant.  Passing a negative argument  to  a  command  that
+       acts  in the forward direction (e.g., kill-line) causes that command to
+       act in a backward direction.  Commands whose  behavior  with  arguments
+       deviates from this are noted below.
+       When  a command is described as killing text, the text deleted is saved
+       for possible future retrieval (yanking).  The killed text is saved in a
+       kill ring.  Consecutive kills cause the text to be accumulated into one
+       unit, which can be yanked all at once.  Commands which do not kill text
+       separate the chunks of text on the kill ring.
+   Readline Initialization
+       Readline  is  customized  by putting commands in an initialization file
+       (the inputrc file).  The name of this file is taken from the  value  of
+       the  INPUTRC  variable.   If  that  variable  is  unset, the default is
+       ~/.inputrc.  When a program which uses the readline library starts  up,
+       the initialization file is read, and the key bindings and variables are
+       set.  There are only a few basic constructs  allowed  in  the  readline
+       initialization  file.  Blank lines are ignored.  Lines beginning with a
+       # are comments.  Lines beginning with a  $  indicate  conditional  con-
+       structs.  Other lines denote key bindings and variable settings.
+       The  default  key-bindings  may be changed with an inputrc file.  Other
+       programs that use this library may add their own commands and bindings.
+       For example, placing
+              M-Control-u: universal-argument
+       or
+              C-Meta-u: universal-argument
+       into  the inputrc would make M-C-u execute the readline command univer-
+       sal-argument.
+       The following symbolic character names  are  recognized:  RUBOUT,  DEL,
+       ESC, LFD, NEWLINE, RET, RETURN, SPC, SPACE, and TAB.
+       In  addition  to  command  names, readline allows keys to be bound to a
+       string that is inserted when the key is pressed (a macro).
+   Readline Key Bindings
+       The syntax for controlling key bindings in the inputrc file is  simple.
+       All  that is required is the name of the command or the text of a macro
+       and a key sequence to which it should be bound. The name may be  speci-
+       fied in one of two ways: as a symbolic key name, possibly with Meta- or
+       Control- prefixes, or as a key sequence.
+       When using the form keyname:function-name or macro, keyname is the name
+       of a key spelled out in English.  For example:
+              Control-u: universal-argument
+              Meta-Rubout: backward-kill-word
+              Control-o: "> output"
+       In  the above example, C-u is bound to the function universal-argument,
+       M-DEL is bound to the function backward-kill-word, and C-o is bound  to
+       run  the macro expressed on the right hand side (that is, to insert the
+       text ``> output'' into the line).
+       In the second form, "keyseq":function-name  or  macro,  keyseq  differs
+       from  keyname above in that strings denoting an entire key sequence may
+       be specified by placing the sequence within double  quotes.   Some  GNU
+       Emacs  style  key escapes can be used, as in the following example, but
+       the symbolic character names are not recognized.
+              "\C-u": universal-argument
+              "\C-x\C-r": re-read-init-file
+              "\e[11~": "Function Key 1"
+       In this example, C-u is again bound to the function universal-argument.
+       C-x  C-r is bound to the function re-read-init-file, and ESC [ 1 1 ~ is
+       bound to insert the text ``Function Key 1''.
+       The full set of GNU Emacs style escape sequences is
+              \C-    control prefix
+              \M-    meta prefix
+              \e     an escape character
+              \\     backslash
+              \"     literal "
+              \'     literal '
+       In addition to the GNU Emacs style escape sequences, a  second  set  of
+       backslash escapes is available:
+              \a     alert (bell)
+              \b     backspace
+              \d     delete
+              \f     form feed
+              \n     newline
+              \r     carriage return
+              \t     horizontal tab
+              \v     vertical tab
+              \nnn   the  eight-bit  character  whose value is the octal value
+                     nnn (one to three digits)
+              \xHH   the eight-bit character whose value  is  the  hexadecimal
+                     value HH (one or two hex digits)
+       When entering the text of a macro, single or double quotes must be used
+       to indicate a macro definition.  Unquoted text is assumed to be a func-
+       tion  name.   In  the macro body, the backslash escapes described above
+       are expanded.  Backslash will quote any other character  in  the  macro
+       text, including " and '.
+       Bash  allows the current readline key bindings to be displayed or modi-
+       fied with the bind builtin command.  The editing mode may  be  switched
+       during  interactive  use by using the -o option to the set builtin com-
+       mand (see SHELL BUILTIN COMMANDS below).
+   Readline Variables
+       Readline has variables that can be used to further customize its behav-
+       ior.  A variable may be set in the inputrc file with a statement of the
+       form
+              set variable-name value
+       Except where noted, readline variables can take the values  On  or  Off
+       (without  regard  to  case).   Unrecognized variable names are ignored.
+       When a variable value is read, empty or null values, "on"  (case-insen-
+       sitive), and "1" are equivalent to On.  All other values are equivalent
+       to Off.  The variables and their default values are:
+       bell-style (audible)
+              Controls what happens when readline wants to ring  the  terminal
+              bell.  If set to none, readline never rings the bell.  If set to
+              visible, readline uses a visible bell if one is  available.   If
+              set to audible, readline attempts to ring the terminal's bell.
+       bind-tty-special-chars (On)
+              If  set  to On, readline attempts to bind the control characters
+              treated specially by the kernel's terminal driver to their read-
+              line equivalents.
+       comment-begin (``#'')
+              The  string  that  is  inserted when the readline insert-comment
+              command is executed.  This command is bound to M-# in emacs mode
+              and to # in vi command mode.
+       completion-ignore-case (Off)
+              If set to On, readline performs filename matching and completion
+              in a case-insensitive fashion.
+       completion-query-items (100)
+              This determines when the user is queried about viewing the  num-
+              ber  of  possible  completions generated by the possible-comple-
+              tions command.  It may be set to any integer value greater  than
+              or  equal  to  zero.   If  the number of possible completions is
+              greater than or equal to the value of this variable, the user is
+              asked  whether or not he wishes to view them; otherwise they are
+              simply listed on the terminal.
+       convert-meta (On)
+              If set to On, readline will convert characters with  the  eighth
+              bit set to an ASCII key sequence by stripping the eighth bit and
+              prefixing an escape character (in effect, using  escape  as  the
+              meta prefix).
+       disable-completion (Off)
+              If set to On, readline will inhibit word completion.  Completion
+              characters will be inserted into the line as if  they  had  been
+              mapped to self-insert.
+       editing-mode (emacs)
+              Controls whether readline begins with a set of key bindings sim-
+              ilar to emacs or vi.  editing-mode can be set to either emacs or
+              vi.
+       enable-keypad (Off)
+              When set to On, readline will try to enable the application key-
+              pad when it is called.  Some systems need  this  to  enable  the
+              arrow keys.
+       expand-tilde (Off)
+              If  set  to  on,  tilde  expansion  is  performed  when readline
+              attempts word completion.
+       history-preserve-point (Off)
+              If set to on, the history code attempts to place  point  at  the
+              same  location on each history line retrieved with previous-his-
+              tory or next-history.
+       horizontal-scroll-mode (Off)
+              When set to On, makes readline use a single  line  for  display,
+              scrolling the input horizontally on a single screen line when it
+              becomes longer than the screen width rather than wrapping  to  a
+              new line.
+       input-meta (Off)
+              If  set to On, readline will enable eight-bit input (that is, it
+              will not strip the high  bit  from  the  characters  it  reads),
+              regardless of what the terminal claims it can support.  The name
+              meta-flag is a synonym for this variable.
+       isearch-terminators (``C-[C-J'')
+              The string of characters that should  terminate  an  incremental
+              search  without  subsequently  executing the character as a com-
+              mand.  If this variable has not been given a value, the  charac-
+              ters ESC and C-J will terminate an incremental search.
+       keymap (emacs)
+              Set  the current readline keymap.  The set of valid keymap names
+              is emacs, emacs-standard, emacs-meta,  emacs-ctlx,  vi,  vi-com-
+              mand,  and  vi-insert.  vi is equivalent to vi-command; emacs is
+              equivalent to emacs-standard.  The default value is  emacs;  the
+              value of editing-mode also affects the default keymap.
+       mark-directories (On)
+              If set to On, completed directory names have a slash appended.
+       mark-modified-lines (Off)
+              If  set  to  On,  history lines that have been modified are dis-
+              played with a preceding asterisk (*).
+       mark-symlinked-directories (Off)
+              If set to On, completed names which are symbolic links to direc-
+              tories   have   a  slash  appended  (subject  to  the  value  of
+              mark-directories).
+       match-hidden-files (On)
+              This variable, when set to On, causes readline  to  match  files
+              whose  names  begin  with  a  `.' (hidden files) when performing
+              filename completion, unless the leading `.' is supplied  by  the
+              user in the filename to be completed.
+       output-meta (Off)
+              If  set  to On, readline will display characters with the eighth
+              bit set directly rather than as a meta-prefixed escape sequence.
+       page-completions (On)
+              If  set to On, readline uses an internal more-like pager to dis-
+              play a screenful of possible completions at a time.
+       print-completions-horizontally (Off)
+              If set to On, readline will  display  completions  with  matches
+              sorted  horizontally in alphabetical order, rather than down the
+              screen.
+       show-all-if-ambiguous (Off)
+              This alters the default behavior of  the  completion  functions.
+              If set to on, words which have more than one possible completion
+              cause the matches to be listed immediately  instead  of  ringing
+              the bell.
+       show-all-if-unmodified (Off)
+              This  alters the default behavior of the completion functions in
+              a fashion similar to show-all-if-ambiguous.  If set to on, words
+              which  have more than one possible completion without any possi-
+              ble partial completion (the possible completions don't  share  a
+              common  prefix)  cause  the  matches  to  be  listed immediately
+              instead of ringing the bell.
+       visible-stats (Off)
+              If set to On, a character denoting a file's type as reported  by
+              stat(2)  is  appended to the filename when listing possible com-
+              pletions.
+   Readline Conditional Constructs
+       Readline implements a facility similar in  spirit  to  the  conditional
+       compilation  features  of  the C preprocessor which allows key bindings
+       and variable settings to be performed as the result  of  tests.   There
+       are four parser directives used.
+       $if    The  $if construct allows bindings to be made based on the edit-
+              ing mode, the terminal being  used,  or  the  application  using
+              readline.   The text of the test extends to the end of the line;
+              no characters are required to isolate it.
+              mode   The mode= form of the  $if  directive  is  used  to  test
+                     whether  readline  is  in  emacs or vi mode.  This may be
+                     used in conjunction with  the  set  keymap  command,  for
+                     instance,  to  set  bindings  in  the  emacs-standard and
+                     emacs-ctlx keymaps only if readline is  starting  out  in
+                     emacs mode.
+              term   The  term=  form may be used to include terminal-specific
+                     key bindings, perhaps to bind the key sequences output by
+                     the terminal's function keys.  The word on the right side
+                     of the = is tested against the both full name of the ter-
+                     minal  and  the  portion  of the terminal name before the
+                     first -.  This allows sun to match both sun and  sun-cmd,
+                     for instance.
+              application
+                     The application construct is used to include application-
+                     specific  settings.   Each  program  using  the  readline
+                     library  sets the application name, and an initialization
+                     file can test for a particular value.  This could be used
+                     to  bind key sequences to functions useful for a specific
+                     program.  For instance, the following command adds a  key
+                     sequence  that  quotes  the  current  or previous word in
+                     Bash:
+                     $if Bash
+                     # Quote the current or previous word
+                     "\C-xq": "\eb\"\ef\""
+                     $endif
+       $endif This command, as seen in the previous example, terminates an $if
+              command.
+       $else  Commands in this branch of the $if directive are executed if the
+              test fails.
+       $include
+              This directive takes a single filename as an argument and  reads
+              commands  and bindings from that file.  For example, the follow-
+              ing directive would read /etc/inputrc:
+              $include  /etc/inputrc
+   Searching
+       Readline provides commands for searching through  the  command  history
+       (see HISTORY below) for lines containing a specified string.  There are
+       two search modes: incremental and non-incremental.
+       Incremental searches begin before the  user  has  finished  typing  the
+       search  string.  As each character of the search string is typed, read-
+       line displays the next entry from the history matching the string typed
+       so  far.   An  incremental  search  requires only as many characters as
+       needed to find the desired history entry.  The  characters  present  in
+       the  value of the isearch-terminators variable are used to terminate an
+       incremental search.  If that variable has not been assigned a value the
+       Escape  and  Control-J characters will terminate an incremental search.
+       Control-G will abort an incremental search  and  restore  the  original
+       line.   When the search is terminated, the history entry containing the
+       search string becomes the current line.
+       To find other matching entries in the history list, type  Control-S  or
+       Control-R  as appropriate.  This will search backward or forward in the
+       history for the next entry matching the search  string  typed  so  far.
+       Any  other  key sequence bound to a readline command will terminate the
+       search and execute that command.  For instance, a newline  will  termi-
+       nate the search and accept the line, thereby executing the command from
+       the history list.
+       Readline remembers the last incremental search string.  If two Control-
+       Rs  are  typed without any intervening characters defining a new search
+       string, any remembered search string is used.
+       Non-incremental searches read the entire search string before  starting
+       to  search  for matching history lines.  The search string may be typed
+       by the user or be part of the contents of the current line.
+   Readline Command Names
+       The following is a list of the names of the commands  and  the  default
+       key sequences to which they are bound.  Command names without an accom-
+       panying key sequence are unbound by default.  In the following descrip-
+       tions,  point refers to the current cursor position, and mark refers to
+       a cursor position saved by the set-mark command.  The text between  the
+       point and mark is referred to as the region.
+   Commands for Moving
+       beginning-of-line (C-a)
+              Move to the start of the current line.
+       end-of-line (C-e)
+              Move to the end of the line.
+       forward-char (C-f)
+              Move forward a character.
+       backward-char (C-b)
+              Move back a character.
+       forward-word (M-f)
+              Move forward to the end of the next word.  Words are composed of
+              alphanumeric characters (letters and digits).
+       backward-word (M-b)
+              Move back to the start of the current or previous  word.   Words
+              are composed of alphanumeric characters (letters and digits).
+       clear-screen (C-l)
+              Clear  the  screen  leaving  the  current line at the top of the
+              screen.  With an argument,  refresh  the  current  line  without
+              clearing the screen.
+       redraw-current-line
+              Refresh the current line.
+   Commands for Manipulating the History
+       accept-line (Newline, Return)
+              Accept the line regardless of where the cursor is.  If this line
+              is non-empty, add it to the history list according to the  state
+              of  the HISTCONTROL variable.  If the line is a modified history
+              line, then restore the history line to its original state.
+       previous-history (C-p)
+              Fetch the previous command from the history list, moving back in
+              the list.
+       next-history (C-n)
+              Fetch  the next command from the history list, moving forward in
+              the list.
+       beginning-of-history (M-<)
+              Move to the first line in the history.
+       end-of-history (M->)
+              Move to the end of the input history, i.e., the  line  currently
+              being entered.
+       reverse-search-history (C-r)
+              Search  backward  starting  at  the current line and moving `up'
+              through the  history  as  necessary.   This  is  an  incremental
+              search.
+       forward-search-history (C-s)
+              Search  forward  starting  at the current line and moving `down'
+              through the  history  as  necessary.   This  is  an  incremental
+              search.
+       non-incremental-reverse-search-history (M-p)
+              Search backward through the history starting at the current line
+              using a non-incremental search for  a  string  supplied  by  the
+              user.
+       non-incremental-forward-search-history (M-n)
+              Search  forward  through  the  history  using  a non-incremental
+              search for a string supplied by the user.
+       history-search-forward
+              Search forward through the history for the string of  characters
+              between  the start of the current line and the point.  This is a
+              non-incremental search.
+       history-search-backward
+              Search backward through the history for the string of characters
+              between  the start of the current line and the point.  This is a
+              non-incremental search.
+       yank-nth-arg (M-C-y)
+              Insert the first argument to the previous command  (usually  the
+              second word on the previous line) at point.  With an argument n,
+              insert the nth word from the previous command (the words in  the
+              previous  command  begin  with  word  0).   A  negative argument
+              inserts the nth word from the end of the previous command.  Once
+              the  argument n is computed, the argument is extracted as if the
+              "!n" history expansion had been specified.
+       yank-last-arg (M-., M-_)
+              Insert the last argument to the previous command (the last  word
+              of  the  previous  history  entry).   With  an  argument, behave
+              exactly like yank-nth-arg.  Successive  calls  to  yank-last-arg
+              move  back through the history list, inserting the last argument
+              of each line in turn.  The history expansion facilities are used
+              to  extract  the last argument, as if the "!$" history expansion
+              had been specified.
+       shell-expand-line (M-C-e)
+              Expand the line as the shell does.  This performs alias and his-
+              tory expansion as well as all of the shell word expansions.  See
+              HISTORY EXPANSION below for a description of history  expansion.
+       history-expand-line (M-^)
+              Perform  history  expansion  on  the  current line.  See HISTORY
+              EXPANSION below for a description of history expansion.
+       magic-space
+              Perform history expansion on  the  current  line  and  insert  a
+              space.  See HISTORY EXPANSION below for a description of history
+              expansion.
+       alias-expand-line
+              Perform alias expansion on the current line.  See ALIASES  above
+              for a description of alias expansion.
+       history-and-alias-expand-line
+              Perform history and alias expansion on the current line.
+       insert-last-argument (M-., M-_)
+              A synonym for yank-last-arg.
+       operate-and-get-next (C-o)
+              Accept  the  current  line for execution and fetch the next line
+              relative to the current line from the history for editing.   Any
+              argument is ignored.
+       edit-and-execute-command (C-xC-e)
+              Invoke  an  editor  on the current command line, and execute the
+              result as shell commands.   Bash  attempts  to  invoke  $FCEDIT,
+              $EDITOR, and emacs as the editor, in that order.
+   Commands for Changing Text
+       delete-char (C-d)
+              Delete  the character at point.  If point is at the beginning of
+              the line, there are no characters in  the  line,  and  the  last
+              character typed was not bound to delete-char, then return EOF.
+       backward-delete-char (Rubout)
+              Delete  the  character  behind the cursor.  When given a numeric
+              argument, save the deleted text on the kill ring.
+       forward-backward-delete-char
+              Delete the character under the cursor, unless the cursor  is  at
+              the end of the line, in which case the character behind the cur-
+              sor is deleted.
+       quoted-insert (C-q, C-v)
+              Add the next character typed to the line verbatim.  This is  how
+              to insert characters like C-q, for example.
+       tab-insert (C-v TAB)
+              Insert a tab character.
+       self-insert (a, b, A, 1, !, ...)
+              Insert the character typed.
+       transpose-chars (C-t)
+              Drag  the  character  before point forward over the character at
+              point, moving point forward as well.  If point is at the end  of
+              the  line, then this transposes the two characters before point.
+              Negative arguments have no effect.
+       transpose-words (M-t)
+              Drag the word before point past the  word  after  point,  moving
+              point  over  that  word  as well.  If point is at the end of the
+              line, this transposes the last two words on the line.
+       upcase-word (M-u)
+              Uppercase the current (or  following)  word.   With  a  negative
+              argument, uppercase the previous word, but do not move point.
+       downcase-word (M-l)
+              Lowercase  the  current  (or  following)  word.  With a negative
+              argument, lowercase the previous word, but do not move point.
+       capitalize-word (M-c)
+              Capitalize the current (or following)  word.   With  a  negative
+              argument, capitalize the previous word, but do not move point.
+       overwrite-mode
+              Toggle  overwrite mode.  With an explicit positive numeric argu-
+              ment, switches to overwrite mode.  With an explicit non-positive
+              numeric argument, switches to insert mode.  This command affects
+              only emacs mode; vi mode does overwrite differently.  Each  call
+              to readline() starts in insert mode.  In overwrite mode, charac-
+              ters bound to self-insert replace the text at point rather  than
+              pushing  the  text  to  the  right.   Characters  bound to back-
+              ward-delete-char replace  the  character  before  point  with  a
+              space.  By default, this command is unbound.
+   Killing and Yanking
+       kill-line (C-k)
+              Kill the text from point to the end of the line.
+       backward-kill-line (C-x Rubout)
+              Kill backward to the beginning of the line.
+       unix-line-discard (C-u)
+              Kill  backward  from  point  to  the beginning of the line.  The
+              killed text is saved on the kill-ring.
+       kill-whole-line
+              Kill all characters on the current line, no matter  where  point
+              is.
+       kill-word (M-d)
+              Kill  from  point  to the end of the current word, or if between
+              words, to the end of the next word.   Word  boundaries  are  the
+              same as those used by forward-word.
+       backward-kill-word (M-Rubout)
+              Kill  the  word  behind  point.  Word boundaries are the same as
+              those used by backward-word.
+       unix-word-rubout (C-w)
+              Kill the word behind point, using white space as a  word  bound-
+              ary.  The killed text is saved on the kill-ring.
+       unix-filename-rubout
+              Kill  the  word  behind  point,  using white space and the slash
+              character as the word boundaries.  The killed text is  saved  on
+              the kill-ring.
+       delete-horizontal-space (M-\)
+              Delete all spaces and tabs around point.
+       kill-region
+              Kill the text in the current region.
+       copy-region-as-kill
+              Copy the text in the region to the kill buffer.
+       copy-backward-word
+              Copy  the word before point to the kill buffer.  The word bound-
+              aries are the same as backward-word.
+       copy-forward-word
+              Copy the word following point to  the  kill  buffer.   The  word
+              boundaries are the same as forward-word.
+       yank (C-y)
+              Yank the top of the kill ring into the buffer at point.
+       yank-pop (M-y)
+              Rotate  the kill ring, and yank the new top.  Only works follow-
+              ing yank or yank-pop.
+   Numeric Arguments
+       digit-argument (M-0, M-1, ..., M--)
+              Add this digit to the argument already accumulating, or start  a
+              new argument.  M-- starts a negative argument.
+       universal-argument
+              This  is another way to specify an argument.  If this command is
+              followed by one or more digits, optionally with a leading  minus
+              sign,  those digits define the argument.  If the command is fol-
+              lowed by digits, executing  universal-argument  again  ends  the
+              numeric  argument, but is otherwise ignored.  As a special case,
+              if this command is immediately followed by a character  that  is
+              neither  a  digit or minus sign, the argument count for the next
+              command is multiplied by four.  The argument count is  initially
+              one,  so  executing this function the first time makes the argu-
+              ment count four, a second time makes the argument count sixteen,
+              and so on.
+   Completing
+       complete (TAB)
+              Attempt  to  perform  completion on the text before point.  Bash
+              attempts completion treating the text as a variable (if the text
+              begins  with  $), username (if the text begins with ~), hostname
+              (if the text begins with @), or command (including  aliases  and
+              functions) in turn.  If none of these produces a match, filename
+              completion is attempted.
+       possible-completions (M-?)
+              List the possible completions of the text before point.
+       insert-completions (M-*)
+              Insert all completions of the text before point that would  have
+              been generated by possible-completions.
+       menu-complete
+              Similar  to complete, but replaces the word to be completed with
+              a single match from the list of possible completions.   Repeated
+              execution  of  menu-complete  steps through the list of possible
+              completions, inserting each match in turn.  At the  end  of  the
+              list of completions, the bell is rung (subject to the setting of
+              bell-style) and the original text is restored.  An argument of n
+              moves  n  positions  forward  in the list of matches; a negative
+              argument may be used to move backward through  the  list.   This
+              command  is  intended  to  be  bound  to  TAB, but is unbound by
+              default.
+       delete-char-or-list
+              Deletes the character under the cursor if not at  the  beginning
+              or  end  of  the  line (like delete-char).  If at the end of the
+              line, behaves identically to possible-completions.  This command
+              is unbound by default.
+       complete-filename (M-/)
+              Attempt filename completion on the text before point.
+       possible-filename-completions (C-x /)
+              List the possible completions of the text before point, treating
+              it as a filename.
+       complete-username (M-~)
+              Attempt completion on the text before point, treating  it  as  a
+              username.
+       possible-username-completions (C-x ~)
+              List the possible completions of the text before point, treating
+              it as a username.
+       complete-variable (M-$)
+              Attempt completion on the text before point, treating  it  as  a
+              shell variable.
+       possible-variable-completions (C-x $)
+              List the possible completions of the text before point, treating
+              it as a shell variable.
+       complete-hostname (M-@)
+              Attempt completion on the text before point, treating  it  as  a
+              hostname.
+       possible-hostname-completions (C-x @)
+              List the possible completions of the text before point, treating
+              it as a hostname.
+       complete-command (M-!)
+              Attempt completion on the text before point, treating  it  as  a
+              command  name.   Command  completion  attempts to match the text
+              against  aliases,  reserved  words,   shell   functions,   shell
+              builtins, and finally executable filenames, in that order.
+       possible-command-completions (C-x !)
+              List the possible completions of the text before point, treating
+              it as a command name.
+       dynamic-complete-history (M-TAB)
+              Attempt completion on the text before point, comparing the  text
+              against  lines  from  the  history  list for possible completion
+              matches.
+       complete-into-braces (M-{)
+              Perform filename completion and insert the list of possible com-
+              pletions  enclosed within braces so the list is available to the
+              shell (see Brace Expansion above).
+   Keyboard Macros
+       start-kbd-macro (C-x ()
+              Begin saving the characters  typed  into  the  current  keyboard
+              macro.
+       end-kbd-macro (C-x ))
+              Stop saving the characters typed into the current keyboard macro
+              and store the definition.
+       call-last-kbd-macro (C-x e)
+              Re-execute the last keyboard macro defined, by making the  char-
+              acters in the macro appear as if typed at the keyboard.
+   Miscellaneous
+       re-read-init-file (C-x C-r)
+              Read  in  the  contents of the inputrc file, and incorporate any
+              bindings or variable assignments found there.
+       abort (C-g)
+              Abort the current editing command and ring the  terminal's  bell
+              (subject to the setting of bell-style).
+       do-uppercase-version (M-a, M-b, M-x, ...)
+              If  the  metafied character x is lowercase, run the command that
+              is bound to the corresponding uppercase character.
+       prefix-meta (ESC)
+              Metafy the next character typed.  ESC f is equivalent to Meta-f.
+       undo (C-_, C-x C-u)
+              Incremental undo, separately remembered for each line.
+       revert-line (M-r)
+              Undo  all changes made to this line.  This is like executing the
+              undo command enough times to return  the  line  to  its  initial
+              state.
+       tilde-expand (M-&)
+              Perform tilde expansion on the current word.
+       set-mark (C-@, M-<space>)
+              Set  the  mark to the point.  If a numeric argument is supplied,
+              the mark is set to that position.
+       exchange-point-and-mark (C-x C-x)
+              Swap the point with the mark.  The current  cursor  position  is
+              set  to the saved position, and the old cursor position is saved
+              as the mark.
+       character-search (C-])
+              A character is read and point is moved to the next occurrence of
+              that  character.   A negative count searches for previous occur-
+              rences.
+       character-search-backward (M-C-])
+              A character is read and point is moved to  the  previous  occur-
+              rence  of  that character.  A negative count searches for subse-
+              quent occurrences.
+       insert-comment (M-#)
+              Without a numeric argument,  the  value  of  the  readline  com-
+              ment-begin  variable is inserted at the beginning of the current
+              line.  If a numeric argument is supplied, this command acts as a
+              toggle:   if  the characters at the beginning of the line do not
+              match the value of comment-begin, the value is inserted,  other-
+              wise the characters in comment-begin are deleted from the begin-
+              ning of the line.  In either case, the line is accepted as if  a
+              newline  had  been  typed.   The  default value of comment-begin
+              causes this command to make the current line  a  shell  comment.
+              If  a  numeric  argument  causes  the  comment  character  to be
+              removed, the line will be executed by the shell.
+       glob-complete-word (M-g)
+              The word before point is  treated  as  a  pattern  for  pathname
+              expansion,  with  an asterisk implicitly appended.  This pattern
+              is used to generate a list of matching file names  for  possible
+              completions.
+       glob-expand-word (C-x *)
+              The  word  before  point  is  treated  as a pattern for pathname
+              expansion, and the list of  matching  file  names  is  inserted,
+              replacing  the  word.   If  a  numeric  argument is supplied, an
+              asterisk is appended before pathname expansion.
+       glob-list-expansions (C-x g)
+              The list  of  expansions  that  would  have  been  generated  by
+              glob-expand-word  is  displayed,  and the line is redrawn.  If a
+              numeric argument is supplied, an  asterisk  is  appended  before
+              pathname expansion.
+       dump-functions
+              Print  all  of the functions and their key bindings to the read-
+              line output stream.  If a numeric argument is supplied, the out-
+              put  is  formatted  in such a way that it can be made part of an
+              inputrc file.
+       dump-variables
+              Print all of the settable readline variables and their values to
+              the  readline output stream.  If a numeric argument is supplied,
+              the output is formatted in such a way that it can be  made  part
+              of an inputrc file.
+       dump-macros
+              Print  all of the readline key sequences bound to macros and the
+              strings they output.  If a numeric  argument  is  supplied,  the
+              output is formatted in such a way that it can be made part of an
+              inputrc file.
+       display-shell-version (C-x C-v)
+              Display version information about the current instance of  bash.
+   Programmable Completion
+       When  word  completion  is  attempted  for an argument to a command for
+       which a completion specification (a compspec) has  been  defined  using
+       the  complete  builtin  (see  SHELL  BUILTIN  COMMANDS below), the pro-
+       grammable completion facilities are invoked.
+       First, the command name is identified.  If a compspec has been  defined
+       for that command, the compspec is used to generate the list of possible
+       completions for the word.  If the command word is a  full  pathname,  a
+       compspec  for  the full pathname is searched for first.  If no compspec
+       is found for the full pathname, an attempt is made to find  a  compspec
+       for the portion following the final slash.
+       Once  a  compspec  has  been  found, it is used to generate the list of
+       matching words.  If a compspec is not found, the default  bash  comple-
+       tion as described above under Completing is performed.
+       First,  the  actions  specified by the compspec are used.  Only matches
+       which are prefixed by the word being completed are returned.  When  the
+       -f  or -d option is used for filename or directory name completion, the
+       shell variable FIGNORE is used to filter the matches.
+       Any completions specified by a filename expansion  pattern  to  the  -G
+       option are generated next.  The words generated by the pattern need not
+       match the word being completed.  The GLOBIGNORE shell variable  is  not
+       used to filter the matches, but the FIGNORE variable is used.
+       Next,  the string specified as the argument to the -W option is consid-
+       ered.  The string is first split using the characters in the  IFS  spe-
+       cial  variable  as delimiters.  Shell quoting is honored.  Each word is
+       then expanded using brace expansion,  tilde  expansion,  parameter  and
+       variable  expansion, command substitution, and arithmetic expansion, as
+       described above under EXPANSION.  The results are split using the rules
+       described above under Word Splitting.  The results of the expansion are
+       prefix-matched against the word being completed, and the matching words
+       become the possible completions.
+       After  these matches have been generated, any shell function or command
+       specified with the -F and -C options is invoked.  When the  command  or
+       function  is  invoked,  the  COMP_LINE  and  COMP_POINT  variables  are
+       assigned values as described above under Shell Variables.  If  a  shell
+       function  is being invoked, the COMP_WORDS and COMP_CWORD variables are
+       also set.  When the function or command is invoked, the first  argument
+       is  the  name  of  the command whose arguments are being completed, the
+       second argument is the word being completed, and the third argument  is
+       the  word  preceding  the  word  being completed on the current command
+       line.  No filtering of the generated completions against the word being
+       completed is performed; the function or command has complete freedom in
+       generating the matches.
+       Any function specified with -F is invoked first.  The function may  use
+       any  of  the  shell facilities, including the compgen builtin described
+       below, to generate the matches.  It must put the  possible  completions
+       in the COMPREPLY array variable.
+       Next,  any  command specified with the -C option is invoked in an envi-
+       ronment equivalent to command substitution.  It should print a list  of
+       completions,  one  per  line, to the standard output.  Backslash may be
+       used to escape a newline, if necessary.
+       After all of the possible completions are generated, any filter  speci-
+       fied  with  the -X option is applied to the list.  The filter is a pat-
+       tern as used for pathname expansion; a & in  the  pattern  is  replaced
+       with  the text of the word being completed.  A literal & may be escaped
+       with a backslash; the backslash is removed before attempting  a  match.
+       Any  completion that matches the pattern will be removed from the list.
+       A leading ! negates the pattern; in this case any completion not match-
+       ing the pattern will be removed.
+       Finally, any prefix and suffix specified with the -P and -S options are
+       added to each member of the completion list, and the result is returned
+       to the readline completion code as the list of possible completions.
+       If  the previously-applied actions do not generate any matches, and the
+       -o dirnames option was supplied  to  complete  when  the  compspec  was
+       defined, directory name completion is attempted.
+       If  the  -o  plusdirs option was supplied to complete when the compspec
+       was defined, directory name completion is attempted and any matches are
+       added to the results of the other actions.
+       By  default,  if a compspec is found, whatever it generates is returned
+       to the completion code as the full set of  possible  completions.   The
+       default bash completions are not attempted, and the readline default of
+       filename completion is disabled.  If the -o bashdefault option was sup-
+       plied  to complete when the compspec was defined, the bash default com-
+       pletions are attempted if the compspec generates no matches.  If the -o
+       default  option was supplied to complete when the compspec was defined,
+       readline's default completion will be performed if the  compspec  (and,
+       if attempted, the default bash completions) generate no matches.
+       When  a  compspec  indicates that directory name completion is desired,
+       the programmable completion functions force readline to append a  slash
+       to  completed names which are symbolic links to directories, subject to
+       the value of the mark-directories readline variable, regardless of  the
+       setting of the mark-symlinked-directories readline variable.
+HISTORY
+       When  the  -o  history  option to the set builtin is enabled, the shell
+       provides access to the command history, the list of commands previously
+       typed.   The  value  of  the HISTSIZE variable is used as the number of
+       commands to save in a history list.  The text of the last HISTSIZE com-
+       mands  (default  500)  is  saved.  The shell stores each command in the
+       history list prior to parameter and variable expansion  (see  EXPANSION
+       above)  but after history expansion is performed, subject to the values
+       of the shell variables HISTIGNORE and HISTCONTROL.
+       On startup, the history is initialized from the file named by the vari-
+       able  HISTFILE  (default ~/.bash_history).  The file named by the value
+       of HISTFILE is truncated, if necessary, to contain  no  more  than  the
+       number of lines specified by the value of HISTFILESIZE.  When an inter-
+       active shell exits, the last $HISTSIZE lines are copied from  the  his-
+       tory list to $HISTFILE.  If the histappend shell option is enabled (see
+       the description of shopt under SHELL BUILTIN COMMANDS below), the lines
+       are  appended  to the history file, otherwise the history file is over-
+       written.  If HISTFILE is unset, or if the history file  is  unwritable,
+       the  history  is not saved.  After saving the history, the history file
+       is truncated to contain no more than HISTFILESIZE lines.  If  HISTFILE-
+       SIZE is not set, no truncation is performed.
+       The  builtin  command fc (see SHELL BUILTIN COMMANDS below) may be used
+       to list or edit and re-execute a portion of the history list.  The his-
+       tory  builtin  may  be  used  to display or modify the history list and
+       manipulate the history file.  When using command-line  editing,  search
+       commands  are available in each editing mode that provide access to the
+       history list.
+       The shell allows control over which commands are saved on  the  history
+       list.  The HISTCONTROL and HISTIGNORE variables may be set to cause the
+       shell to save only a subset of the commands entered.  The cmdhist shell
+       option,  if enabled, causes the shell to attempt to save each line of a
+       multi-line command in the same history entry, adding  semicolons  where
+       necessary  to preserve syntactic correctness.  The lithist shell option
+       causes the shell to save the command with embedded newlines instead  of
+       semicolons.  See the description of the shopt builtin below under SHELL
+       BUILTIN  COMMANDS  for  information  on  setting  and  unsetting  shell
+       options.
+HISTORY EXPANSION
+       The  shell  supports a history expansion feature that is similar to the
+       history expansion in csh.  This section describes what syntax  features
+       are  available.   This  feature  is  enabled by default for interactive
+       shells, and can be disabled using the +H option to the set builtin com-
+       mand (see SHELL BUILTIN COMMANDS below).  Non-interactive shells do not
+       perform history expansion by default.
+       History expansions introduce words from the history list into the input
+       stream,  making  it  easy to repeat commands, insert the arguments to a
+       previous command into the current input line, or fix errors in previous
+       commands quickly.
+       History  expansion  is  performed  immediately after a complete line is
+       read, before the shell breaks it into words.  It  takes  place  in  two
+       parts.   The  first is to determine which line from the history list to
+       use during substitution.  The second is to select portions of that line
+       for inclusion into the current one.  The line selected from the history
+       is the event, and the portions of that line that  are  acted  upon  are
+       words.   Various  modifiers  are  available  to manipulate the selected
+       words.  The line is broken into words in the same fashion as when read-
+       ing  input, so that several metacharacter-separated words surrounded by
+       quotes are considered one word.  History expansions are  introduced  by
+       the  appearance  of  the  history  expansion  character,  which is ! by
+       default.  Only backslash (\) and single quotes can  quote  the  history
+       expansion character.
+       Several  characters inhibit history expansion if found immediately fol-
+       lowing the history expansion character, even if it is unquoted:  space,
+       tab,  newline,  carriage return, and =.  If the extglob shell option is
+       enabled, ( will also inhibit expansion.
+       Several shell options settable with the shopt builtin may  be  used  to
+       tailor  the  behavior  of  history  expansion.  If the histverify shell
+       option is enabled (see the description of the shopt builtin), and read-
+       line is being used, history substitutions are not immediately passed to
+       the shell parser.  Instead, the expanded  line  is  reloaded  into  the
+       readline editing buffer for further modification.  If readline is being
+       used, and the histreedit shell option is enabled, a failed history sub-
+       stitution will be reloaded into the readline editing buffer for correc-
+       tion.  The -p option to the history builtin command may be used to  see
+       what a history expansion will do before using it.  The -s option to the
+       history builtin may be used to add commands to the end of  the  history
+       list  without  actually  executing them, so that they are available for
+       subsequent recall.
+       The shell allows control of the various characters used by the  history
+       expansion mechanism (see the description of histchars above under Shell
+       Variables).
+   Event Designators
+       An event designator is a reference to a command line entry in the  his-
+       tory list.
+       !      Start  a  history substitution, except when followed by a blank,
+              newline, carriage return, = or ( (when the extglob shell  option
+              is enabled using the shopt builtin).
+       !n     Refer to command line n.
+       !-n    Refer to the current command line minus n.
+       !!     Refer to the previous command.  This is a synonym for `!-1'.
+       !string
+              Refer to the most recent command starting with string.
+       !?string[?]
+              Refer  to the most recent command containing string.  The trail-
+              ing ? may be omitted if string is followed immediately by a new-
+              line.
+       ^string1^string2^
+              Quick  substitution.  Repeat the last command, replacing string1
+              with string2.  Equivalent to ``!!:s/string1/string2/'' (see Mod-
+              ifiers below).
+       !#     The entire command line typed so far.
+   Word Designators
+       Word  designators are used to select desired words from the event.  A :
+       separates the event specification from the word designator.  It may  be
+       omitted  if  the word designator begins with a ^, $, *, -, or %.  Words
+       are numbered from the beginning of the line, with the first word  being
+       denoted  by  0  (zero).  Words are inserted into the current line sepa-
+       rated by single spaces.
+(zero)
+              The zeroth word.  For the shell, this is the command word.
+       n      The nth word.
+       ^      The first argument.  That is, word 1.
+       $      The last argument.
+       %      The word matched by the most recent `?string?' search.
+       x-y    A range of words; `-y' abbreviates `0-y'.
+       *      All of the words but the zeroth.  This is a synonym  for  `1-$'.
+              It  is  not  an  error to use * if there is just one word in the
+              event; the empty string is returned in that case.
+       x*     Abbreviates x-$.
+       x-     Abbreviates x-$ like x*, but omits the last word.
+       If a word designator is supplied without an  event  specification,  the
+       previous command is used as the event.
+   Modifiers
+       After  the optional word designator, there may appear a sequence of one
+       or more of the following modifiers, each preceded by a `:'.
+       h      Remove a trailing file name component, leaving only the head.
+       t      Remove all leading file name components, leaving the tail.
+       r      Remove a trailing suffix of the form .xxx, leaving the basename.
+       e      Remove all but the trailing suffix.
+       p      Print the new command but do not execute it.
+       q      Quote the substituted words, escaping further substitutions.
+       x      Quote  the  substituted words as with q, but break into words at
+              blanks and newlines.
+       s/old/new/
+              Substitute new for the first occurrence  of  old  in  the  event
+              line.   Any  delimiter  can  be  used  in place of /.  The final
+              delimiter is optional if it is the last character of  the  event
+              line.   The delimiter may be quoted in old and new with a single
+              backslash.  If & appears in new, it is replaced by old.  A  sin-
+              gle  backslash  will  quote the &.  If old is null, it is set to
+              the last old substituted, or, if no previous  history  substitu-
+              tions took place, the last string in a !?string[?]  search.
+       &      Repeat the previous substitution.
+       g      Cause changes to be applied over the entire event line.  This is
+              used in conjunction with `:s' (e.g.,  `:gs/old/new/')  or  `:&'.
+              If  used with `:s', any delimiter can be used in place of /, and
+              the final delimiter is optional if it is the last  character  of
+              the event line.  An a may be used as a synonym for g.
+       G      Apply  the following `s' modifier once to each word in the event
+              line.
+SHELL BUILTIN COMMANDS
+       Unless otherwise noted, each builtin command documented in this section
+       as accepting options preceded by - accepts -- to signify the end of the
+       options.  For example, the :, true, false, and  test  builtins  do  not
+       accept options.
+       : [arguments]
+              No  effect;  the command does nothing beyond expanding arguments
+              and performing any specified redirections.  A zero exit code  is
+              returned.
+        .  filename [arguments]
+       source filename [arguments]
+              Read  and  execute  commands  from filename in the current shell
+              environment and return the exit status of the last command  exe-
+              cuted from filename.  If filename does not contain a slash, file
+              names in PATH are used to find the  directory  containing  file-
+              name.   The  file  searched  for in PATH need not be executable.
+              When bash is  not  in  posix  mode,  the  current  directory  is
+              searched  if no file is found in PATH.  If the sourcepath option
+              to the shopt builtin command is turned  off,  the  PATH  is  not
+              searched.   If any arguments are supplied, they become the posi-
+              tional parameters when  filename  is  executed.   Otherwise  the
+              positional  parameters  are unchanged.  The return status is the
+              status of the last command exited within the  script  (0  if  no
+              commands  are  executed),  and false if filename is not found or
+              cannot be read.
+       alias [-p] [name[=value] ...]
+              Alias with no arguments or with the -p option prints the list of
+              aliases  in  the form alias name=value on standard output.  When
+              arguments are supplied, an alias is defined for each name  whose
+              value is given.  A trailing space in  value causes the next word
+              to be checked for alias substitution when the alias is expanded.
+              For  each  name  in the argument list for which no value is sup-
+              plied, the name and  value  of  the  alias  is  printed.   Alias
+              returns  true unless a name is given for which no alias has been
+              defined.
+       bg [jobspec ...]
+              Resume each suspended job jobspec in the background,  as  if  it
+              had been started with &.  If jobspec is not present, the shell's
+              notion of the current job is used.  bg jobspec returns 0  unless
+              run  when  job control is disabled or, when run with job control
+              enabled, any specified jobspec was  not  found  or  was  started
+              without job control.
+       bind [-m keymap] [-lpsvPSV]
+       bind [-m keymap] [-q function] [-u function] [-r keyseq]
+       bind [-m keymap] -f filename
+       bind [-m keymap] -x keyseq:shell-command
+       bind [-m keymap] keyseq:function-name
+       bind readline-command
+              Display  current  readline key and function bindings, bind a key
+              sequence to a readline function or  macro,  or  set  a  readline
+              variable.   Each  non-option  argument  is a command as it would
+              appear in .inputrc, but each binding or command must  be  passed
+              as  a  separate argument; e.g., '"\C-x\C-r": re-read-init-file'.
+              Options, if supplied, have the following meanings:
+              -m keymap
+                     Use keymap as the keymap to be affected by the subsequent
+                     bindings.  Acceptable keymap names are emacs, emacs-stan-
+                     dard, emacs-meta, emacs-ctlx,  vi,  vi-move,  vi-command,
+                     and  vi-insert.  vi is equivalent to vi-command; emacs is
+                     equivalent to emacs-standard.
+              -l     List the names of all readline functions.
+              -p     Display readline function names and bindings  in  such  a
+                     way that they can be re-read.
+              -P     List current readline function names and bindings.
+              -v     Display  readline variable names and values in such a way
+                     that they can be re-read.
+              -V     List current readline variable names and values.
+              -s     Display readline key sequences bound to  macros  and  the
+                     strings  they  output  in such a way that they can be re-
+                     read.
+              -S     Display readline key sequences bound to  macros  and  the
+                     strings they output.
+              -f filename
+                     Read key bindings from filename.
+              -q function
+                     Query about which keys invoke the named function.
+              -u function
+                     Unbind all keys bound to the named function.
+              -r keyseq
+                     Remove any current binding for keyseq.
+              -x keyseq:shell-command
+                     Cause  shell-command  to  be  executed whenever keyseq is
+                     entered.
+              The return value is 0 unless an unrecognized option is given  or
+              an error occurred.
+       break [n]
+              Exit  from  within a for, while, until, or select loop.  If n is
+              specified, break n levels.  n must be >= 1.   If  n  is  greater
+              than  the  number  of  enclosing  loops, all enclosing loops are
+              exited.  The return value is 0 unless the shell is not executing
+              a loop when break is executed.
+       builtin shell-builtin [arguments]
+              Execute  the  specified shell builtin, passing it arguments, and
+              return its exit status.  This is useful when defining a function
+              whose  name  is the same as a shell builtin, retaining the func-
+              tionality of the builtin within the function.  The cd builtin is
+              commonly  redefined  this  way.   The  return status is false if
+              shell-builtin is not a shell builtin command.
+       cd [-L|-P] [dir]
+              Change the current directory to dir.  The variable HOME  is  the
+              default  dir.   The  variable CDPATH defines the search path for
+              the directory containing dir.  Alternative  directory  names  in
+              CDPATH  are  separated by a colon (:).  A null directory name in
+              CDPATH is the same as the current directory,  i.e.,  ``.''.   If
+              dir  begins  with  a  slash (/), then CDPATH is not used. The -P
+              option says to use the physical directory structure  instead  of
+              following  symbolic  links  (see  also  the -P option to the set
+              builtin command); the -L option forces symbolic links to be fol-
+              lowed.   An  argument  of - is equivalent to $OLDPWD.  If a non-
+              empty directory name from CDPATH is used, or if - is  the  first
+              argument,  and  the directory change is successful, the absolute
+              pathname of the new working directory is written to the standard
+              output.   The return value is true if the directory was success-
+              fully changed; false otherwise.
+       caller [expr]
+              Returns the context of any active subroutine call (a shell func-
+              tion  or a script executed with the . or source builtins.  With-
+              out expr, caller displays the line number and source filename of
+              the  current subroutine call.  If a non-negative integer is sup-
+              plied as expr, caller displays the line number, subroutine name,
+              and  source  file  corresponding to that position in the current
+              execution call stack.  This extra information may be  used,  for
+              example,  to print a stack trace.  The current frame is frame 0.
+              The return value is 0 unless the shell is not executing  a  sub-
+              routine  call or expr does not correspond to a valid position in
+              the call stack.
+       command [-pVv] command [arg ...]
+              Run command with args  suppressing  the  normal  shell  function
+              lookup.  Only builtin commands or commands found in the PATH are
+              executed.  If the -p option is given, the search for command  is
+              performed  using  a default value for PATH that is guaranteed to
+              find all of the standard utilities.  If  either  the  -V  or  -v
+              option is supplied, a description of command is printed.  The -v
+              option causes a single word indicating the command or file  name
+              used to invoke command to be displayed; the -V option produces a
+              more verbose description.  If the -V or -v option  is  supplied,
+              the  exit  status  is  0 if command was found, and 1 if not.  If
+              neither option is supplied and an error occurred or command can-
+              not  be found, the exit status is 127.  Otherwise, the exit sta-
+              tus of the command builtin is the exit status of command.
+       compgen [option] [word]
+              Generate possible completion matches for word according  to  the
+              options,  which  may  be  any  option  accepted  by the complete
+              builtin with the exception of -p and -r, and write  the  matches
+              to  the  standard  output.  When using the -F or -C options, the
+              various shell  variables  set  by  the  programmable  completion
+              facilities, while available, will not have useful values.
+              The  matches  will  be  generated in the same way as if the pro-
+              grammable completion code had generated  them  directly  from  a
+              completion specification with the same flags.  If word is speci-
+              fied, only those completions matching word will be displayed.
+              The return value is true unless an invalid option  is  supplied,
+              or no matches were generated.
+       complete  [-abcdefgjksuv] [-o comp-option] [-A action] [-G globpat] [-W
+       wordlist] [-P prefix] [-S suffix]
+              [-X filterpat] [-F function] [-C command] name [name ...]
+       complete -pr [name ...]
+              Specify  how arguments to each name should be completed.  If the
+              -p option is supplied, or if no options are  supplied,  existing
+              completion  specifications are printed in a way that allows them
+              to be reused as input.  The -r option removes a completion spec-
+              ification  for each name, or, if no names are supplied, all com-
+              pletion specifications.
+              The process of applying  these  completion  specifications  when
+              word  completion  is  attempted  is  described  above under Pro-
+              grammable Completion.
+              Other options, if specified, have the following  meanings.   The
+              arguments  to the -G, -W, and -X options (and, if necessary, the
+              -P and -S options) should be quoted to protect them from  expan-
+              sion before the complete builtin is invoked.
+              -o comp-option
+                      The  comp-option  controls  several aspects of the comp-
+                      spec's behavior beyond the simple generation of  comple-
+                      tions.  comp-option may be one of:
+                      bashdefault
+                              Perform the rest of the default bash completions
+                              if the compspec generates no matches.
+                      default Use readline's default  filename  completion  if
+                              the compspec generates no matches.
+                      dirnames
+                              Perform  directory  name completion if the comp-
+                              spec generates no matches.
+                      filenames
+                              Tell readline that the compspec generates  file-
+                              names,  so  it can perform any filename-specific
+                              processing (like adding  a  slash  to  directory
+                              names or suppressing trailing spaces).  Intended
+                              to be used with shell functions.
+                      nospace Tell  readline  not  to  append  a  space   (the
+                              default)  to  words  completed at the end of the
+                              line.
+                      plusdirs
+                              After any matches defined by  the  compspec  are
+                              generated,    directory   name   completion   is
+                              attempted and  any  matches  are  added  to  the
+                              results of the other actions.
+              -A action
+                      The  action  may  be  one of the following to generate a
+                      list of possible completions:
+                      alias   Alias names.  May also be specified as -a.
+                      arrayvar
+                              Array variable names.
+                      binding Readline key binding names.
+                      builtin Names of shell builtin commands.   May  also  be
+                              specified as -b.
+                      command Command names.  May also be specified as -c.
+                      directory
+                              Directory names.  May also be specified as -d.
+                      disabled
+                              Names of disabled shell builtins.
+                      enabled Names of enabled shell builtins.
+                      export  Names  of exported shell variables.  May also be
+                              specified as -e.
+                      file    File names.  May also be specified as -f.
+                      function
+                              Names of shell functions.
+                      group   Group names.  May also be specified as -g.
+                      helptopic
+                              Help topics as accepted by the help builtin.
+                      hostname
+                              Hostnames, as taken from the file  specified  by
+                              the HOSTFILE shell variable.
+                      job     Job  names,  if job control is active.  May also
+                              be specified as -j.
+                      keyword Shell reserved words.  May also be specified  as
+                              -k.
+                      running Names of running jobs, if job control is active.
+                      service Service names.  May also be specified as -s.
+                      setopt  Valid arguments for the -o  option  to  the  set
+                              builtin.
+                      shopt   Shell  option  names  as  accepted  by the shopt
+                              builtin.
+                      signal  Signal names.
+                      stopped Names of stopped jobs, if job control is active.
+                      user    User names.  May also be specified as -u.
+                      variable
+                              Names of all shell variables.  May also be spec-
+                              ified as -v.
+              -G globpat
+                      The filename expansion pattern globpat  is  expanded  to
+                      generate the possible completions.
+              -W wordlist
+                      The  wordlist  is  split using the characters in the IFS
+                      special variable as delimiters, and each resultant  word
+                      is  expanded.   The possible completions are the members
+                      of the resultant list which match the  word  being  com-
+                      pleted.
+              -C command
+                      command  is  executed in a subshell environment, and its
+                      output is used as the possible completions.
+              -F function
+                      The shell function function is executed in  the  current
+                      shell  environment.  When it finishes, the possible com-
+                      pletions are retrieved from the value of  the  COMPREPLY
+                      array variable.
+              -X filterpat
+                      filterpat  is  a pattern as used for filename expansion.
+                      It is applied to the list of possible completions gener-
+                      ated  by  the  preceding options and arguments, and each
+                      completion matching filterpat is removed from the  list.
+                      A  leading  !  in filterpat negates the pattern; in this
+                      case, any completion not matching filterpat is  removed.
+              -P prefix
+                      prefix  is  added at the beginning of each possible com-
+                      pletion after all other options have been applied.
+              -S suffix
+                      suffix is appended to each possible completion after all
+                      other options have been applied.
+              The  return  value is true unless an invalid option is supplied,
+              an option other than -p or -r is supplied without a  name  argu-
+              ment,  an  attempt  is made to remove a completion specification
+              for a name for which no specification exists, or an error occurs
+              adding a completion specification.
+       continue [n]
+              Resume the next iteration of the enclosing for, while, until, or
+              select loop.  If n is specified, resume  at  the  nth  enclosing
+              loop.   n  must  be  >=  1.   If n is greater than the number of
+              enclosing loops, the  last  enclosing  loop  (the  ``top-level''
+              loop) is resumed.  The return value is 0 unless the shell is not
+              executing a loop when continue is executed.
+       declare [-afFirtx] [-p] [name[=value] ...]
+       typeset [-afFirtx] [-p] [name[=value] ...]
+              Declare variables and/or give them attributes.  If no names  are
+              given  then display the values of variables.  The -p option will
+              display the attributes and values of  each  name.   When  -p  is
+              used,  additional  options  are ignored.  The -F option inhibits
+              the display of function definitions; only the function name  and
+              attributes are printed.  If the extdebug shell option is enabled
+              using shopt, the source file name  and  line  number  where  the
+              function  is  defined  are  displayed  as  well.   The -F option
+              implies -f.  The following options can be used to restrict  out-
+              put  to  variables with the specified attribute or to give vari-
+              ables attributes:
+              -a     Each name is an array variable (see Arrays above).
+              -f     Use function names only.
+              -i     The variable is treated as an integer; arithmetic evalua-
+                     tion  (see  ARITHMETIC EVALUATION ) is performed when the
+                     variable is assigned a value.
+              -r     Make names readonly.  These names cannot then be assigned
+                     values by subsequent assignment statements or unset.
+              -t     Give  each  name  the  trace attribute.  Traced functions
+                     inherit the DEBUG  and  RETURN  traps  from  the  calling
+                     shell.   The  trace  attribute has no special meaning for
+                     variables.
+              -x     Mark names for export  to  subsequent  commands  via  the
+                     environment.
+              Using  `+'  instead of `-' turns off the attribute instead, with
+              the exception that +a may not be used to destroy an array  vari-
+              able.   When  used in a function, makes each name local, as with
+              the local command.  If a variable name is  followed  by  =value,
+              the  value of the variable is set to value.  The return value is
+unless an invalid option is encountered, an attempt is made to
+              define  a  function  using ``-f foo=bar'', an attempt is made to
+              assign a value to a readonly variable, an  attempt  is  made  to
+              assign  a  value to an array variable without using the compound
+              assignment syntax (see Arrays above), one of the names is not  a
+              valid  shell variable name, an attempt is made to turn off read-
+              only status for a readonly variable, an attempt is made to  turn
+              off array status for an array variable, or an attempt is made to
+              display a non-existent function with -f.
+       dirs [-clpv] [+n] [-n]
+              Without options,  displays  the  list  of  currently  remembered
+              directories.   The  default  display  is  on  a single line with
+              directory names separated by spaces.  Directories are  added  to
+              the  list  with  the  pushd  command;  the  popd command removes
+              entries from the list.
+              +n     Displays the nth entry counting from the left of the list
+                     shown by dirs when invoked without options, starting with
+                     zero.
+              -n     Displays the nth entry counting from  the  right  of  the
+                     list shown by dirs when invoked without options, starting
+                     with zero.
+              -c     Clears  the  directory  stack  by  deleting  all  of  the
+                     entries.
+              -l     Produces  a  longer  listing;  the default listing format
+                     uses a tilde to denote the home directory.
+              -p     Print the directory stack with one entry per line.
+              -v     Print the directory stack with one entry per  line,  pre-
+                     fixing each entry with its index in the stack.
+              The  return value is 0 unless an invalid option is supplied or n
+              indexes beyond the end of the directory stack.
+       disown [-ar] [-h] [jobspec ...]
+              Without options, each jobspec  is  removed  from  the  table  of
+              active  jobs.   If  the  -h option is given, each jobspec is not
+              removed from the table, but is marked so that SIGHUP is not sent
+              to  the  job  if  the shell receives a SIGHUP.  If no jobspec is
+              present, and neither the -a nor the -r option is  supplied,  the
+              current  job  is used.  If no jobspec is supplied, the -a option
+              means to remove or mark all jobs; the -r option without  a  job-
+              spec  argument  restricts operation to running jobs.  The return
+              value is 0 unless a jobspec does not specify a valid job.
+       echo [-neE] [arg ...]
+              Output the args, separated by spaces,  followed  by  a  newline.
+              The return status is always 0.  If -n is specified, the trailing
+              newline is suppressed.  If the -e option is  given,  interpreta-
+              tion  of  the following backslash-escaped characters is enabled.
+              The -E option disables the interpretation of these escape  char-
+              acters,  even  on systems where they are interpreted by default.
+              The xpg_echo shell option may be used to  dynamically  determine
+              whether  or not echo expands these escape characters by default.
+              echo does not interpret -- to mean the  end  of  options.   echo
+              interprets the following escape sequences:
+              \a     alert (bell)
+              \b     backspace
+              \c     suppress trailing newline
+              \e     an escape character
+              \f     form feed
+              \n     new line
+              \r     carriage return
+              \t     horizontal tab
+              \v     vertical tab
+              \\     backslash
+              \0nnn  the  eight-bit  character  whose value is the octal value
+                     nnn (zero to three octal digits)
+              \xHH   the eight-bit character whose value  is  the  hexadecimal
+                     value HH (one or two hex digits)
+       enable [-adnps] [-f filename] [name ...]
+              Enable  and disable builtin shell commands.  Disabling a builtin
+              allows a disk command which has the same name as a shell builtin
+              to  be  executed without specifying a full pathname, even though
+              the shell normally searches for builtins before  disk  commands.
+              If  -n  is  used,  each  name  is disabled; otherwise, names are
+              enabled.  For example, to use the test binary found via the PATH
+              instead  of  the  shell builtin version, run ``enable -n test''.
+              The -f option means to load the new builtin  command  name  from
+              shared object filename, on systems that support dynamic loading.
+              The -d option will delete a builtin previously loaded  with  -f.
+              If no name arguments are given, or if the -p option is supplied,
+              a list of shell builtins is printed.  With no other option argu-
+              ments,  the  list consists of all enabled shell builtins.  If -n
+              is supplied, only disabled builtins are printed.  If -a is  sup-
+              plied,  the  list printed includes all builtins, with an indica-
+              tion of whether or not each is enabled.  If -s is supplied,  the
+              output  is restricted to the POSIX special builtins.  The return
+              value is 0 unless a name is not a shell builtin or there  is  an
+              error loading a new builtin from a shared object.
+       eval [arg ...]
+              The  args  are read and concatenated together into a single com-
+              mand.  This command is then read and executed by the shell,  and
+              its  exit status is returned as the value of eval.  If there are
+              no args, or only null arguments, eval returns 0.
+       exec [-cl] [-a name] [command [arguments]]
+              If command is specified, it replaces the shell.  No new  process
+              is  created.  The arguments become the arguments to command.  If
+              the -l option is supplied, the shell places a dash at the begin-
+              ning of the zeroth arg passed to command.  This is what login(1)
+              does.  The -c option causes command to be executed with an empty
+              environment.   If  -a  is supplied, the shell passes name as the
+              zeroth argument to the executed command.  If command  cannot  be
+              executed  for some reason, a non-interactive shell exits, unless
+              the shell option execfail is enabled, in which case  it  returns
+              failure.   An interactive shell returns failure if the file can-
+              not be executed.  If command is not specified, any  redirections
+              take  effect  in  the current shell, and the return status is 0.
+              If there is a redirection error, the return status is 1.
+       exit [n]
+              Cause the shell to exit with a status of n.  If  n  is  omitted,
+              the exit status is that of the last command executed.  A trap on
+              EXIT is executed before the shell terminates.
+       export [-fn] [name[=word]] ...
+       export -p
+              The supplied names are marked for automatic export to the  envi-
+              ronment  of subsequently executed commands.  If the -f option is
+              given, the names refer to functions.  If no names are given,  or
+              if  the  -p  option  is  supplied,  a list of all names that are
+              exported in this shell is printed.  The  -n  option  causes  the
+              export  property  to  be  removed from each name.  If a variable
+              name is followed by =word, the value of the variable is  set  to
+              word.   export  returns  an  exit  status of 0 unless an invalid
+              option is encountered, one of the names is  not  a  valid  shell
+              variable name, or -f is supplied with a name that is not a func-
+              tion.
+       fc [-e ename] [-nlr] [first] [last]
+       fc -s [pat=rep] [cmd]
+              Fix Command.  In the first form, a range of commands from  first
+              to  last  is selected from the history list.  First and last may
+              be specified as a string (to locate the last  command  beginning
+              with  that  string)  or  as  a number (an index into the history
+              list, where a negative number is used as an offset from the cur-
+              rent command number).  If last is not specified it is set to the
+              current command for listing (so that ``fc -l  -10''  prints  the
+              last 10 commands) and to first otherwise.  If first is not spec-
+              ified it is set to the previous command for editing and -16  for
+              listing.
+              The  -n option suppresses the command numbers when listing.  The
+              -r option reverses the order of the commands.  If the -l  option
+              is  given,  the  commands are listed on standard output.  Other-
+              wise, the editor given by ename is invoked on a file  containing
+              those  commands.  If ename is not given, the value of the FCEDIT
+              variable is used, and the value of EDITOR if FCEDIT is not  set.
+              If  neither  variable  is set, vi is used.  When editing is com-
+              plete, the edited commands are echoed and executed.
+              In the second form, command is re-executed after  each  instance
+              of  pat  is replaced by rep.  A useful alias to use with this is
+              ``r="fc -s"'', so that typing ``r cc''  runs  the  last  command
+              beginning with ``cc'' and typing ``r'' re-executes the last com-
+              mand.
+              If the first form is used, the  return  value  is  0  unless  an
+              invalid  option  is encountered or first or last specify history
+              lines out of range.  If the -e option is  supplied,  the  return
+              value is the value of the last command executed or failure if an
+              error occurs with the temporary file of commands.  If the second
+              form  is  used, the return status is that of the command re-exe-
+              cuted, unless cmd does not specify  a  valid  history  line,  in
+              which case fc returns failure.
+       fg [jobspec]
+              Resume  jobspec  in the foreground, and make it the current job.
+              If jobspec is not present, the shell's notion of the current job
+              is  used.   The  return value is that of the command placed into
+              the foreground, or failure if run when job control  is  disabled
+              or, when run with job control enabled, if jobspec does not spec-
+              ify a valid job or jobspec specifies  a  job  that  was  started
+              without job control.
+       getopts optstring name [args]
+              getopts  is used by shell procedures to parse positional parame-
+              ters.  optstring contains the option  characters  to  be  recog-
+              nized;  if  a  character  is  followed by a colon, the option is
+              expected to have an argument, which should be separated from  it
+              by  white space.  The colon and question mark characters may not
+              be used as option characters.  Each time it is invoked,  getopts
+              places  the next option in the shell variable name, initializing
+              name if it does not exist, and the index of the next argument to
+              be processed into the variable OPTIND.  OPTIND is initialized to
+each time the shell or a shell script  is  invoked.   When  an
+              option  requires  an argument, getopts places that argument into
+              the variable OPTARG.  The shell does not reset OPTIND  automati-
+              cally;  it  must  be  manually  reset  between multiple calls to
+              getopts within the same shell invocation if a new set of parame-
+              ters is to be used.
+              When  the  end  of  options is encountered, getopts exits with a
+              return value greater than zero.  OPTIND is set to the  index  of
+              the first non-option argument, and name is set to ?.
+              getopts  normally  parses the positional parameters, but if more
+              arguments are given in args, getopts parses those instead.
+              getopts can report errors in two ways.  If the  first  character
+              of  optstring  is  a  colon, silent error reporting is used.  In
+              normal operation diagnostic messages are  printed  when  invalid
+              options  or  missing  option  arguments are encountered.  If the
+              variable OPTERR is set to 0, no  error  messages  will  be  dis-
+              played, even if the first character of optstring is not a colon.
+              If an invalid option is seen, getopts places ? into name and, if
+              not  silent,  prints  an  error  message  and unsets OPTARG.  If
+              getopts is silent, the  option  character  found  is  placed  in
+              OPTARG and no diagnostic message is printed.
+              If  a required argument is not found, and getopts is not silent,
+              a question mark (?) is placed in name, OPTARG is  unset,  and  a
+              diagnostic  message  is  printed.   If getopts is silent, then a
+              colon (:) is placed in name and OPTARG  is  set  to  the  option
+              character found.
+              getopts  returns true if an option, specified or unspecified, is
+              found.  It returns false if the end of options is encountered or
+              an error occurs.
+       hash [-lr] [-p filename] [-dt] [name]
+              For  each  name, the full file name of the command is determined
+              by searching the directories in $PATH and remembered.  If the -p
+              option is supplied, no path search is performed, and filename is
+              used as the full file name of the command.  The -r option causes
+              the  shell  to  forget  all remembered locations.  The -d option
+              causes the shell to forget the remembered location of each name.
+              If  the  -t  option is supplied, the full pathname to which each
+              name corresponds is printed.  If  multiple  name  arguments  are
+              supplied  with  -t,  the  name is printed before the hashed full
+              pathname.  The -l option causes output to be displayed in a for-
+              mat  that may be reused as input.  If no arguments are given, or
+              if only -l is supplied, information about remembered commands is
+              printed.   The  return status is true unless a name is not found
+              or an invalid option is supplied.
+       help [-s] [pattern]
+              Display helpful information about builtin commands.  If  pattern
+              is  specified, help gives detailed help on all commands matching
+              pattern; otherwise help for all the builtins and  shell  control
+              structures  is printed.  The -s option restricts the information
+              displayed to a short usage synopsis.  The  return  status  is  0
+              unless no command matches pattern.
+       history [n]
+       history -c
+       history -d offset
+       history -anrw [filename]
+       history -p arg [arg ...]
+       history -s arg [arg ...]
+              With no options, display the command history list with line num-
+              bers.  Lines listed with a * have been modified.  An argument of
+              n  lists only the last n lines.  If the shell variable HISTTIME-
+              FORMAT is set and not null, it is used as a  format  string  for
+              strftime(3)  to display the time stamp associated with each dis-
+              played history entry.  No intervening blank is  printed  between
+              the  formatted  time stamp and the history line.  If filename is
+              supplied, it is used as the name of the history  file;  if  not,
+              the  value  of HISTFILE is used.  Options, if supplied, have the
+              following meanings:
+              -c     Clear the history list by deleting all the entries.
+              -d offset
+                     Delete the history entry at position offset.
+              -a     Append the ``new'' history lines (history  lines  entered
+                     since  the  beginning of the current bash session) to the
+                     history file.
+              -n     Read the history lines not already read from the  history
+                     file  into  the  current  history  list.  These are lines
+                     appended to the history file since the beginning  of  the
+                     current bash session.
+              -r     Read the contents of the history file and use them as the
+                     current history.
+              -w     Write the current history to the history file,  overwrit-
+                     ing the history file's contents.
+              -p     Perform  history  substitution  on the following args and
+                     display the result on  the  standard  output.   Does  not
+                     store  the results in the history list.  Each arg must be
+                     quoted to disable normal history expansion.
+              -s     Store the args in the history list  as  a  single  entry.
+                     The  last  command  in the history list is removed before
+                     the args are added.
+              If the HISTTIMEFORMAT is set, the time stamp information associ-
+              ated  with  each  history  entry is written to the history file.
+              The return value is 0 unless an invalid option  is  encountered,
+              an  error  occurs  while reading or writing the history file, an
+              invalid offset is supplied as an argument to -d, or the  history
+              expansion supplied as an argument to -p fails.
+       jobs [-lnprs] [ jobspec ... ]
+       jobs -x command [ args ... ]
+              The first form lists the active jobs.  The options have the fol-
+              lowing meanings:
+              -l     List process IDs in addition to the normal information.
+              -p     List only the process  ID  of  the  job's  process  group
+                     leader.
+              -n     Display  information  only  about  jobs that have changed
+                     status since the user was last notified of their  status.
+              -r     Restrict output to running jobs.
+              -s     Restrict output to stopped jobs.
+              If  jobspec  is given, output is restricted to information about
+              that job.  The return status is 0 unless an  invalid  option  is
+              encountered or an invalid jobspec is supplied.
+              If the -x option is supplied, jobs replaces any jobspec found in
+              command or args with the corresponding  process  group  ID,  and
+              executes command passing it args, returning its exit status.
+       kill [-s sigspec | -n signum | -sigspec] [pid | jobspec] ...
+       kill -l [sigspec | exit_status]
+              Send  the  signal  named  by  sigspec or signum to the processes
+              named by pid or jobspec.  sigspec is either  a  case-insensitive
+              signal  name such as SIGKILL (with or without the SIG prefix) or
+              a signal number; signum is a signal number.  If sigspec  is  not
+              present,  then  SIGTERM is assumed.  An argument of -l lists the
+              signal names.  If any arguments are supplied when -l  is  given,
+              the  names  of  the  signals  corresponding to the arguments are
+              listed, and the return status is 0.  The exit_status argument to
+              -l  is  a  number  specifying either a signal number or the exit
+              status of a process terminated by a signal.  kill  returns  true
+              if  at  least  one  signal was successfully sent, or false if an
+              error occurs or an invalid option is encountered.
+       let arg [arg ...]
+              Each arg is an arithmetic expression to be evaluated (see ARITH-
+              METIC  EVALUATION).  If the last arg evaluates to 0, let returns
+; 0 is returned otherwise.
+       local [option] [name[=value] ...]
+              For each argument, a local variable named name is  created,  and
+              assigned  value.   The option can be any of the options accepted
+              by declare.  When local is used within a function, it causes the
+              variable  name  to have a visible scope restricted to that func-
+              tion and its children.  With no operands, local writes a list of
+              local  variables  to the standard output.  It is an error to use
+              local when not within a function.  The return status is 0 unless
+              local  is  used outside a function, an invalid name is supplied,
+              or name is a readonly variable.
+       logout Exit a login shell.
+       popd [-n] [+n] [-n]
+              Removes entries from the directory stack.   With  no  arguments,
+              removes  the  top directory from the stack, and performs a cd to
+              the new top directory.  Arguments, if supplied, have the follow-
+              ing meanings:
+              +n     Removes  the nth entry counting from the left of the list
+                     shown by dirs, starting with zero.  For  example:  ``popd
+                     +0'' removes the first directory, ``popd +1'' the second.
+              -n     Removes the nth entry counting from the right of the list
+                     shown  by  dirs, starting with zero.  For example: ``popd
+                     -0'' removes the last directory, ``popd -1'' the next  to
+                     last.
+              -n     Suppresses  the  normal change of directory when removing
+                     directories from the stack, so that  only  the  stack  is
+                     manipulated.
+              If  the popd command is successful, a dirs is performed as well,
+              and the return status is 0.  popd returns false  if  an  invalid
+              option is encountered, the directory stack is empty, a non-exis-
+              tent directory stack entry is specified, or the directory change
+              fails.
+       printf [-v var] format [arguments]
+              Write  the  formatted arguments to the standard output under the
+              control of the format.  The format is a character  string  which
+              contains  three  types  of  objects: plain characters, which are
+              simply copied to standard output,  character  escape  sequences,
+              which  are converted and copied to the standard output, and for-
+              mat specifications, each of which causes printing  of  the  next
+              successive argument.  In addition to the standard printf(1) for-
+              mats, %b causes printf to expand backslash escape  sequences  in
+              the  corresponding  argument  (except that \c terminates output,
+              backslashes in \', \", and \? are not removed, and octal escapes
+              beginning  with \0 may contain up to four digits), and %q causes
+              printf to output the corresponding argument in a format that can
+              be reused as shell input.
+              The  -v  option causes the output to be assigned to the variable
+              var rather than being printed to the standard output.
+              The format is reused as necessary to consume all  of  the  argu-
+              ments.  If the format requires more arguments than are supplied,
+              the extra format specifications behave as if  a  zero  value  or
+              null  string,  as  appropriate,  had  been supplied.  The return
+              value is zero on success, non-zero on failure.
+       pushd [-n] [dir]
+       pushd [-n] [+n] [-n]
+              Adds a directory to the top of the directory stack,  or  rotates
+              the  stack,  making the new top of the stack the current working
+              directory.  With no arguments, exchanges the top two directories
+              and  returns 0, unless the directory stack is empty.  Arguments,
+              if supplied, have the following meanings:
+              +n     Rotates the stack so that  the  nth  directory  (counting
+                     from  the  left  of the list shown by dirs, starting with
+                     zero) is at the top.
+              -n     Rotates the stack so that  the  nth  directory  (counting
+                     from  the  right of the list shown by dirs, starting with
+                     zero) is at the top.
+              -n     Suppresses the normal change  of  directory  when  adding
+                     directories  to  the  stack,  so  that  only the stack is
+                     manipulated.
+              dir    Adds dir to the directory stack at the top, making it the
+                     new current working directory.
+              If the pushd command is successful, a dirs is performed as well.
+              If the first form is used, pushd returns 0 unless the cd to  dir
+              fails.   With the second form, pushd returns 0 unless the direc-
+              tory stack is empty, a non-existent directory stack  element  is
+              specified,  or the directory change to the specified new current
+              directory fails.
+       pwd [-LP]
+              Print the absolute pathname of the  current  working  directory.
+              The pathname printed contains no symbolic links if the -P option
+              is supplied or the -o physical option to the set builtin command
+              is  enabled.  If the -L option is used, the pathname printed may
+              contain symbolic links.  The return status is 0 unless an  error
+              occurs  while  reading  the  name of the current directory or an
+              invalid option is supplied.
+       read [-ers] [-u fd] [-t timeout] [-a aname] [-p prompt] [-n nchars] [-d
+       delim] [name ...]
+              One line is read from the  standard  input,  or  from  the  file
+              descriptor  fd supplied as an argument to the -u option, and the
+              first word is assigned to the first name, the second word to the
+              second  name, and so on, with leftover words and their interven-
+              ing separators assigned to the last name.  If  there  are  fewer
+              words read from the input stream than names, the remaining names
+              are assigned empty values.  The characters in IFS  are  used  to
+              split  the  line into words.  The backslash character (\) may be
+              used to remove any special meaning for the next  character  read
+              and  for line continuation.  Options, if supplied, have the fol-
+              lowing meanings:
+              -a aname
+                     The words are assigned to sequential indices of the array
+                     variable aname, starting at 0.  aname is unset before any
+                     new  values  are  assigned.   Other  name  arguments  are
+                     ignored.
+              -d delim
+                     The  first  character  of  delim is used to terminate the
+                     input line, rather than newline.
+              -e     If the standard input is coming from a terminal, readline
+                     (see READLINE above) is used to obtain the line.
+              -n nchars
+                     read  returns after reading nchars characters rather than
+                     waiting for a complete line of input.
+              -p prompt
+                     Display prompt on standard error, without a trailing new-
+                     line, before attempting to read any input.  The prompt is
+                     displayed only if input is coming from a terminal.
+              -r     Backslash does not act as an escape character.  The back-
+                     slash  is considered to be part of the line.  In particu-
+                     lar, a backslash-newline pair may not be used as  a  line
+                     continuation.
+              -s     Silent mode.  If input is coming from a terminal, charac-
+                     ters are not echoed.
+              -t timeout
+                     Cause read to time out and return failure if  a  complete
+                     line  of  input is not read within timeout seconds.  This
+                     option has no effect if read is not  reading  input  from
+                     the terminal or a pipe.
+              -u fd  Read input from file descriptor fd.
+              If no names are supplied, the line read is assigned to the vari-
+              able REPLY.  The return code  is  zero,  unless  end-of-file  is
+              encountered,  read  times  out, or an invalid file descriptor is
+              supplied as the argument to -u.
+       readonly [-apf] [name[=word] ...]
+              The given names are marked readonly; the values of  these  names
+              may  not  be changed by subsequent assignment.  If the -f option
+              is supplied, the functions corresponding to  the  names  are  so
+              marked.  The -a option restricts the variables to arrays.  If no
+              name arguments are given, or if the -p  option  is  supplied,  a
+              list  of  all  readonly  names is printed.  The -p option causes
+              output to be displayed in a format that may be reused as  input.
+              If  a variable name is followed by =word, the value of the vari-
+              able is set to word.  The return status is 0 unless  an  invalid
+              option  is  encountered,  one  of the names is not a valid shell
+              variable name, or -f is supplied with a name that is not a func-
+              tion.
+       return [n]
+              Causes  a function to exit with the return value specified by n.
+              If n is omitted, the return status is that of the  last  command
+              executed  in the function body.  If used outside a function, but
+              during execution of a script by  the  .   (source)  command,  it
+              causes the shell to stop executing that script and return either
+              n or the exit status of the last  command  executed  within  the
+              script  as  the  exit  status  of the script.  If used outside a
+              function and not during execution of a script by .,  the  return
+              status is false.  Any command associated with the RETURN trap is
+              executed before execution resumes after the function or  script.
+       set [--abefhkmnptuvxBCHP] [-o option] [arg ...]
+              Without  options,  the name and value of each shell variable are
+              displayed in a format that can be reused as input for setting or
+              resetting the currently-set variables.  Read-only variables can-
+              not be reset.  In posix mode, only shell variables  are  listed.
+              The  output  is  sorted  according  to the current locale.  When
+              options are specified, they set or unset shell attributes.   Any
+              arguments  remaining after the options are processed are treated
+              as values for the positional parameters  and  are  assigned,  in
+              order, to $1, $2, ...  $n.  Options, if specified, have the fol-
+              lowing meanings:
+              -a      Automatically mark variables  and  functions  which  are
+                      modified  or  created  for  export to the environment of
+                      subsequent commands.
+              -b      Report the status of terminated background jobs  immedi-
+                      ately, rather than before the next primary prompt.  This
+                      is effective only when job control is enabled.
+              -e      Exit immediately if a simple command (see SHELL  GRAMMAR
+                      above) exits with a non-zero status.  The shell does not
+                      exit if the command that fails is part  of  the  command
+                      list  immediately  following  a  while or until keyword,
+                      part of the test in an if statement, part of a && or  ||
+                      list, or if the command's return value is being inverted
+                      via !.  A trap on ERR, if set, is  executed  before  the
+                      shell exits.
+              -f      Disable pathname expansion.
+              -h      Remember  the location of commands as they are looked up
+                      for execution.  This is enabled by default.
+              -k      All arguments in the form of assignment  statements  are
+                      placed  in the environment for a command, not just those
+                      that precede the command name.
+              -m      Monitor mode.  Job control is enabled.  This  option  is
+                      on  by  default  for  interactive shells on systems that
+                      support it (see JOB  CONTROL  above).   Background  pro-
+                      cesses  run  in a separate process group and a line con-
+                      taining their exit status is printed upon their  comple-
+                      tion.
+              -n      Read commands but do not execute them.  This may be used
+                      to check a shell script  for  syntax  errors.   This  is
+                      ignored by interactive shells.
+              -o option-name
+                      The option-name can be one of the following:
+                      allexport
+                              Same as -a.
+                      braceexpand
+                              Same as -B.
+                      emacs   Use  an  emacs-style command line editing inter-
+                              face.  This is enabled by default when the shell
+                              is interactive, unless the shell is started with
+                              the --noediting option.
+                      errtrace
+                              Same as -E.
+                      functrace
+                              Same as -T.
+                      errexit Same as -e.
+                      hashall Same as -h.
+                      histexpand
+                              Same as -H.
+                      history Enable command history, as described above under
+                              HISTORY.  This option is on by default in inter-
+                              active shells.
+                      ignoreeof
+                              The  effect  is  as   if   the   shell   command
+                              ``IGNOREEOF=10''  had  been  executed (see Shell
+                              Variables above).
+                      keyword Same as -k.
+                      monitor Same as -m.
+                      noclobber
+                              Same as -C.
+                      noexec  Same as -n.
+                      noglob  Same as -f.  nolog Currently ignored.
+                      notify  Same as -b.
+                      nounset Same as -u.
+                      onecmd  Same as -t.
+                      physical
+                              Same as -P.
+                      pipefail
+                              If set, the return value of a  pipeline  is  the
+                              value  of  the  last (rightmost) command to exit
+                              with a non-zero status, or zero if all  commands
+                              in  the pipeline exit successfully.  This option
+                              is disabled by default.
+                      posix   Change the behavior of bash  where  the  default
+                              operation  differs  from  the  POSIX standard to
+                              match the standard (posix mode).
+                      privileged
+                              Same as -p.
+                      verbose Same as -v.
+                      vi      Use a vi-style command line editing interface.
+                      xtrace  Same as -x.
+                      If -o is supplied with no option-name, the values of the
+                      current  options are printed.  If +o is supplied with no
+                      option-name, a series of set commands  to  recreate  the
+                      current  option  settings  is  displayed on the standard
+                      output.
+              -p      Turn on privileged mode.  In this  mode,  the  $ENV  and
+                      $BASH_ENV  files  are not processed, shell functions are
+                      not inherited from the environment,  and  the  SHELLOPTS
+                      variable,  if it appears in the environment, is ignored.
+                      If the shell is started with the effective user  (group)
+                      id  not  equal  to  the real user (group) id, and the -p
+                      option is not supplied, these actions are taken and  the
+                      effective user id is set to the real user id.  If the -p
+                      option is supplied at startup, the effective user id  is
+                      not reset.  Turning this option off causes the effective
+                      user and group ids to be set to the real user and  group
+                      ids.
+              -t      Exit after reading and executing one command.
+              -u      Treat unset variables as an error when performing param-
+                      eter expansion.  If expansion is attempted on  an  unset
+                      variable, the shell prints an error message, and, if not
+                      interactive, exits with a non-zero status.
+              -v      Print shell input lines as they are read.
+              -x      After expanding each simple command, for  command,  case
+                      command, select command, or arithmetic for command, dis-
+                      play the expanded value of PS4, followed by the  command
+                      and its expanded arguments or associated word list.
+              -B      The  shell performs brace expansion (see Brace Expansion
+                      above).  This is on by default.
+              -C      If set, bash does not overwrite an  existing  file  with
+                      the  >,  >&,  and <> redirection operators.  This may be
+                      overridden when creating output files by using the redi-
+                      rection operator >| instead of >.
+              -E      If set, any trap on ERR is inherited by shell functions,
+                      command substitutions, and commands executed in  a  sub-
+                      shell  environment.  The ERR trap is normally not inher-
+                      ited in such cases.
+              -H      Enable !  style history substitution.  This option is on
+                      by default when the shell is interactive.
+              -P      If  set,  the  shell does not follow symbolic links when
+                      executing commands such as cd that  change  the  current
+                      working  directory.   It  uses  the  physical  directory
+                      structure instead.  By default, bash follows the logical
+                      chain  of  directories  when  performing  commands which
+                      change the current directory.
+              -T      If set, any traps on DEBUG and RETURN are  inherited  by
+                      shell  functions,  command  substitutions,  and commands
+                      executed in  a  subshell  environment.   The  DEBUG  and
+                      RETURN traps are normally not inherited in such cases.
+              --      If  no arguments follow this option, then the positional
+                      parameters are unset.  Otherwise, the positional parame-
+                      ters  are  set  to  the args, even if some of them begin
+                      with a -.
+              -       Signal the end of options, cause all remaining  args  to
+                      be assigned to the positional parameters.  The -x and -v
+                      options are turned off.  If there are no args, the posi-
+                      tional parameters remain unchanged.
+              The  options are off by default unless otherwise noted.  Using +
+              rather than - causes  these  options  to  be  turned  off.   The
+              options  can  also be specified as arguments to an invocation of
+              the shell.  The current set of options may be found in $-.   The
+              return status is always true unless an invalid option is encoun-
+              tered.
+       shift [n]
+              The positional parameters from n+1 ... are renamed  to  $1  ....
+              Parameters  represented  by  the  numbers  $# down to $#-n+1 are
+              unset.  n must be a non-negative number less than  or  equal  to
+              $#.   If  n is 0, no parameters are changed.  If n is not given,
+              it is assumed to be 1.  If n is greater than $#, the  positional
+              parameters  are  not changed.  The return status is greater than
+              zero if n is greater than $# or less than zero; otherwise 0.
+       shopt [-pqsu] [-o] [optname ...]
+              Toggle the values of variables controlling optional shell behav-
+              ior.  With no options, or with the -p option, a list of all set-
+              table options is displayed, with an indication of whether or not
+              each  is  set.  The -p option causes output to be displayed in a
+              form that may be reused as input.  Other options have  the  fol-
+              lowing meanings:
+              -s     Enable (set) each optname.
+              -u     Disable (unset) each optname.
+              -q     Suppresses  normal output (quiet mode); the return status
+                     indicates whether the optname is set or unset.  If multi-
+                     ple  optname arguments are given with -q, the return sta-
+                     tus is zero if all optnames are enabled; non-zero  other-
+                     wise.
+              -o     Restricts  the  values of optname to be those defined for
+                     the -o option to the set builtin.
+              If either -s or -u is used with no optname arguments,  the  dis-
+              play is limited to those options which are set or unset, respec-
+              tively.  Unless otherwise noted, the shopt options are  disabled
+              (unset) by default.
+              The  return  status when listing options is zero if all optnames
+              are enabled, non-zero  otherwise.   When  setting  or  unsetting
+              options,  the  return  status is zero unless an optname is not a
+              valid shell option.
+              The list of shopt options is:
+              cdable_vars
+                      If set, an argument to the cd builtin  command  that  is
+                      not  a directory is assumed to be the name of a variable
+                      whose value is the directory to change to.
+              cdspell If set, minor errors in the spelling of a directory com-
+                      ponent  in  a  cd command will be corrected.  The errors
+                      checked for are transposed characters, a missing charac-
+                      ter,  and  one  character  too many.  If a correction is
+                      found, the corrected file name is printed, and the  com-
+                      mand  proceeds.  This option is only used by interactive
+                      shells.
+              checkhash
+                      If set, bash checks that a command found in the hash ta-
+                      ble  exists  before  trying  to execute it.  If a hashed
+                      command no longer exists, a normal path search  is  per-
+                      formed.
+              checkwinsize
+                      If  set,  bash checks the window size after each command
+                      and, if necessary, updates the values of LINES and  COL-
+                      UMNS.
+              cmdhist If  set,  bash attempts to save all lines of a multiple-
+                      line command in the same  history  entry.   This  allows
+                      easy re-editing of multi-line commands.
+              dotglob If  set, bash includes filenames beginning with a `.' in
+                      the results of pathname expansion.
+              execfail
+                      If set, a non-interactive shell will not exit if it can-
+                      not  execute  the  file  specified as an argument to the
+                      exec builtin command.  An  interactive  shell  does  not
+                      exit if exec fails.
+              expand_aliases
+                      If  set,  aliases  are expanded as described above under
+                      ALIASES.  This option is enabled by default for interac-
+                      tive shells.
+              extdebug
+                      If  set,  behavior  intended  for  use  by  debuggers is
+                      enabled:
+.     The -F option to the declare builtin displays the
+                             source file name and line number corresponding to
+                             each function name supplied as an argument.
+.     If the command run by the DEBUG  trap  returns  a
+                             non-zero  value,  the next command is skipped and
+                             not executed.
+.     If the command run by the DEBUG  trap  returns  a
+                             value  of 2, and the shell is executing in a sub-
+                             routine (a shell function or a shell script  exe-
+                             cuted  by  the  .  or source builtins), a call to
+                             return is simulated.
+.     BASH_ARGC and BASH_ARGV are updated as  described
+                             in their descriptions above.
+.     Function  tracing  is enabled:  command substitu-
+                             tion, shell functions, and subshells invoked with
+                             ( command ) inherit the DEBUG and RETURN traps.
+.     Error  tracing is enabled:  command substitution,
+                             shell functions, and  subshells  invoked  with  (
+                             command ) inherit the ERROR trap.
+              extglob If set, the extended pattern matching features described
+                      above under Pathname Expansion are enabled.
+              extquote
+                      If set, $'string' and  $"string"  quoting  is  performed
+                      within   ${parameter}   expansions  enclosed  in  double
+                      quotes.  This option is enabled by default.
+              failglob
+                      If set, patterns which fail to  match  filenames  during
+                      pathname expansion result in an expansion error.
+              force_fignore
+                      If  set,  the  suffixes  specified  by the FIGNORE shell
+                      variable cause words to be ignored when performing  word
+                      completion even if the ignored words are the only possi-
+                      ble  completions.   See  SHELL  VARIABLES  above  for  a
+                      description  of  FIGNORE.   This  option  is  enabled by
+                      default.
+              gnu_errfmt
+                      If set, shell error messages are written in the standard
+                      GNU error message format.
+              histappend
+                      If  set,  the history list is appended to the file named
+                      by the value of the HISTFILE  variable  when  the  shell
+                      exits, rather than overwriting the file.
+              histreedit
+                      If  set, and readline is being used, a user is given the
+                      opportunity to re-edit a failed history substitution.
+              histverify
+                      If set, and readline is being used, the results of  his-
+                      tory  substitution  are  not  immediately  passed to the
+                      shell parser.  Instead, the  resulting  line  is  loaded
+                      into the readline editing buffer, allowing further modi-
+                      fication.
+              hostcomplete
+                      If set, and readline is being used, bash will attempt to
+                      perform  hostname  completion when a word containing a @
+                      is  being  completed  (see  Completing  under   READLINE
+                      above).  This is enabled by default.
+              huponexit
+                      If set, bash will send SIGHUP to all jobs when an inter-
+                      active login shell exits.
+              interactive_comments
+                      If set, allow a word beginning with # to cause that word
+                      and  all remaining characters on that line to be ignored
+                      in an interactive  shell  (see  COMMENTS  above).   This
+                      option is enabled by default.
+              lithist If  set,  and  the cmdhist option is enabled, multi-line
+                      commands are saved to the history with embedded newlines
+                      rather than using semicolon separators where possible.
+              login_shell
+                      The  shell  sets this option if it is started as a login
+                      shell (see INVOCATION above).   The  value  may  not  be
+                      changed.
+              mailwarn
+                      If  set,  and  a file that bash is checking for mail has
+                      been accessed since the last time it  was  checked,  the
+                      message  ``The  mail in mailfile has been read'' is dis-
+                      played.
+              no_empty_cmd_completion
+                      If set, and  readline  is  being  used,  bash  will  not
+                      attempt to search the PATH for possible completions when
+                      completion is attempted on an empty line.
+              nocaseglob
+                      If set, bash matches  filenames  in  a  case-insensitive
+                      fashion when performing pathname expansion (see Pathname
+                      Expansion above).
+              nocasematch
+                      If set, bash  matches  patterns  in  a  case-insensitive
+                      fashion when performing matching while executing case or
+                      [[ conditional commands.
+              nullglob
+                      If set, bash allows patterns which match no  files  (see
+                      Pathname  Expansion  above)  to expand to a null string,
+                      rather than themselves.
+              progcomp
+                      If set, the programmable completion facilities (see Pro-
+                      grammable Completion above) are enabled.  This option is
+                      enabled by default.
+              promptvars
+                      If set, prompt strings undergo parameter expansion, com-
+                      mand   substitution,  arithmetic  expansion,  and  quote
+                      removal after being expanded as described  in  PROMPTING
+                      above.  This option is enabled by default.
+              restricted_shell
+                      The   shell  sets  this  option  if  it  is  started  in
+                      restricted mode (see RESTRICTED SHELL below).  The value
+                      may  not be changed.  This is not reset when the startup
+                      files are executed, allowing the startup files  to  dis-
+                      cover whether or not a shell is restricted.
+              shift_verbose
+                      If  set,  the shift builtin prints an error message when
+                      the shift count exceeds the number of positional parame-
+                      ters.
+              sourcepath
+                      If set, the source (.) builtin uses the value of PATH to
+                      find the directory containing the file  supplied  as  an
+                      argument.  This option is enabled by default.
+              xpg_echo
+                      If   set,  the  echo  builtin  expands  backslash-escape
+                      sequences by default.
+       suspend [-f]
+              Suspend the execution of this shell until it receives a  SIGCONT
+              signal.   The  -f option says not to complain if this is a login
+              shell; just suspend anyway.  The return status is 0  unless  the
+              shell is a login shell and -f is not supplied, or if job control
+              is not enabled.
+       test expr
+       [ expr ]
+              Return a status of 0 or 1 depending on  the  evaluation  of  the
+              conditional  expression expr.  Each operator and operand must be
+              a separate argument.  Expressions are composed of the  primaries
+              described  above  under  CONDITIONAL EXPRESSIONS.  test does not
+              accept any options, nor does it accept and ignore an argument of
+              -- as signifying the end of options.
+              Expressions  may  be  combined  using  the  following operators,
+              listed in decreasing order of precedence.
+              ! expr True if expr is false.
+              ( expr )
+                     Returns the value of expr.  This may be used to  override
+                     the normal precedence of operators.
+              expr1 -a expr2
+                     True if both expr1 and expr2 are true.
+              expr1 -o expr2
+                     True if either expr1 or expr2 is true.
+              test and [ evaluate conditional expressions using a set of rules
+              based on the number of arguments.
+arguments
+                     The expression is false.
+argument
+                     The expression is true if and only if the argument is not
+                     null.
+arguments
+                     If the first argument is !, the expression is true if and
+                     only if the second argument is null.  If the first  argu-
+                     ment  is  one  of  the unary conditional operators listed
+                     above under CONDITIONAL EXPRESSIONS,  the  expression  is
+                     true if the unary test is true.  If the first argument is
+                     not a valid unary conditional operator, the expression is
+                     false.
+arguments
+                     If  the  second argument is one of the binary conditional
+                     operators listed above under CONDITIONAL EXPRESSIONS, the
+                     result of the expression is the result of the binary test
+                     using the first and third arguments as operands.  If  the
+                     first  argument  is  !,  the value is the negation of the
+                     two-argument test using the second and  third  arguments.
+                     If the first argument is exactly ( and the third argument
+                     is exactly ), the result is the one-argument test of  the
+                     second  argument.   Otherwise,  the  expression is false.
+                     The -a and -o operators are considered  binary  operators
+                     in this case.
+arguments
+                     If the first argument is !, the result is the negation of
+                     the three-argument expression composed of  the  remaining
+                     arguments.  Otherwise, the expression is parsed and eval-
+                     uated according to  precedence  using  the  rules  listed
+                     above.
+or more arguments
+                     The  expression  is  parsed  and  evaluated  according to
+                     precedence using the rules listed above.
+       times  Print the accumulated user and system times for  the  shell  and
+              for processes run from the shell.  The return status is 0.
+       trap [-lp] [[arg] sigspec ...]
+              The  command  arg  is  to  be  read  and executed when the shell
+              receives signal(s) sigspec.  If arg is absent (and  there  is  a
+              single  sigspec)  or  -,  each  specified signal is reset to its
+              original disposition (the value it  had  upon  entrance  to  the
+              shell).   If arg is the null string the signal specified by each
+              sigspec is ignored by the shell and by the commands it  invokes.
+              If  arg  is  not present and -p has been supplied, then the trap
+              commands associated with each  sigspec  are  displayed.   If  no
+              arguments  are  supplied or if only -p is given, trap prints the
+              list of commands associated with each  signal.   The  -l  option
+              causes  the shell to print a list of signal names and their cor-
+              responding numbers.   Each  sigspec  is  either  a  signal  name
+              defined  in  <signal.h>,  or  a signal number.  Signal names are
+              case insensitive and the SIG prefix is optional.  If  a  sigspec
+              is  EXIT (0) the command arg is executed on exit from the shell.
+              If a sigspec is DEBUG, the command arg is executed before  every
+              simple command, for command, case command, select command, every
+              arithmetic for command, and before the first command executes in
+              a  shell  function  (see  SHELL  GRAMMAR  above).   Refer to the
+              description of the extdebug option  to  the  shopt  builtin  for
+              details  of  its effect on the DEBUG trap.  If a sigspec is ERR,
+              the command arg is executed whenever  a  simple  command  has  a
+              non-zero  exit status, subject to the following conditions.  The
+              ERR trap is not executed if the failed command is  part  of  the
+              command  list  immediately  following  a while or until keyword,
+              part of the test in an if statement, part of a && or || list, or
+              if  the  command's  return value is being inverted via !.  These
+              are the same conditions obeyed by  the  errexit  option.   If  a
+              sigspec is RETURN, the command arg is executed each time a shell
+              function or a script executed with the . or source builtins fin-
+              ishes executing.  Signals ignored upon entry to the shell cannot
+              be trapped or reset.  Trapped signals that are not being ignored
+              are reset to their original values in a child process when it is
+              created.  The return status is false if any sigspec is  invalid;
+              otherwise trap returns true.
+       type [-aftpP] name [name ...]
+              With  no options, indicate how each name would be interpreted if
+              used as a command name.  If the -t option is used, type prints a
+              string  which  is  one  of alias, keyword, function, builtin, or
+              file if  name  is  an  alias,  shell  reserved  word,  function,
+              builtin,  or disk file, respectively.  If the name is not found,
+              then nothing  is  printed,  and  an  exit  status  of  false  is
+              returned.   If  the  -p  option is used, type either returns the
+              name of the disk file that would be executed if name were speci-
+              fied as a command name, or nothing if ``type -t name'' would not
+              return file.  The -P option forces a PATH search for each  name,
+              even if ``type -t name'' would not return file.  If a command is
+              hashed, -p and -P print the hashed value,  not  necessarily  the
+              file that appears first in PATH.  If the -a option is used, type
+              prints all of the places that contain an executable named  name.
+              This  includes  aliases  and  functions,  if  and only if the -p
+              option is not also used.  The table of hashed  commands  is  not
+              consulted  when  using -a.  The -f option suppresses shell func-
+              tion lookup, as with the command builtin.  type returns true  if
+              any of the arguments are found, false if none are found.
+       ulimit [-SHacdefilmnpqrstuvx [limit]]
+              Provides  control  over the resources available to the shell and
+              to processes started by it, on systems that allow such  control.
+              The -H and -S options specify that the hard or soft limit is set
+              for the given resource.  A hard limit cannot be  increased  once
+              it  is set; a soft limit may be increased up to the value of the
+              hard limit.  If neither -H nor -S is specified,  both  the  soft
+              and  hard limits are set.  The value of limit can be a number in
+              the unit specified for the resource or one of the special values
+              hard,  soft,  or  unlimited,  which  stand  for the current hard
+              limit, the current soft limit, and no limit,  respectively.   If
+              limit  is  omitted,  the  current value of the soft limit of the
+              resource is printed, unless the -H option is given.   When  more
+              than  one  resource  is  specified,  the limit name and unit are
+              printed before the value.  Other options are interpreted as fol-
+              lows:
+              -a     All current limits are reported
+              -c     The maximum size of core files created
+              -d     The maximum size of a process's data segment
+              -e     The maximum scheduling priority ("nice")
+              -f     The  maximum  size  of files written by the shell and its
+                     children
+              -i     The maximum number of pending signals
+              -l     The maximum size that may be locked into memory
+              -m     The maximum resident set size
+              -n     The maximum number of open file descriptors (most systems
+                     do not allow this value to be set)
+              -p     The pipe size in 512-byte blocks (this may not be set)
+              -q     The maximum number of bytes in POSIX message queues
+              -r     The maximum real-time scheduling priority
+              -s     The maximum stack size
+              -t     The maximum amount of cpu time in seconds
+              -u     The  maximum  number  of  processes available to a single
+                     user
+              -v     The maximum amount of virtual  memory  available  to  the
+                     shell
+              -x     The maximum number of file locks
+              If limit is given, it is the new value of the specified resource
+              (the -a option is display only).  If no option is given, then -f
+              is  assumed.  Values are in 1024-byte increments, except for -t,
+              which is in seconds, -p, which is in units of  512-byte  blocks,
+              and  -n and -u, which are unscaled values.  The return status is
+unless an invalid option or argument is supplied, or an  error
+              occurs while setting a new limit.
+       umask [-p] [-S] [mode]
+              The user file-creation mask is set to mode.  If mode begins with
+              a digit, it is interpreted as an octal number; otherwise  it  is
+              interpreted  as a symbolic mode mask similar to that accepted by
+              chmod(1).  If mode is omitted, the current value of the mask  is
+              printed.   The  -S  option causes the mask to be printed in sym-
+              bolic form; the default output is an octal number.   If  the  -p
+              option is supplied, and mode is omitted, the output is in a form
+              that may be reused as input.  The return status is 0 if the mode
+              was  successfully  changed  or if no mode argument was supplied,
+              and false otherwise.
+       unalias [-a] [name ...]
+              Remove each name from the list of defined  aliases.   If  -a  is
+              supplied,  all  alias definitions are removed.  The return value
+              is true unless a supplied name is not a defined alias.
+       unset [-fv] [name ...]
+              For each name, remove the corresponding  variable  or  function.
+              If no options are supplied, or the -v option is given, each name
+              refers to a shell variable.   Read-only  variables  may  not  be
+              unset.   If  -f  is specified, each name refers to a shell func-
+              tion, and the function definition is removed.  Each unset  vari-
+              able  or function is removed from the environment passed to sub-
+              sequent commands.  If any of RANDOM, SECONDS,  LINENO,  HISTCMD,
+              FUNCNAME, GROUPS, or DIRSTACK are unset, they lose their special
+              properties, even if they are subsequently reset.  The exit  sta-
+              tus is true unless a name is readonly.
+       wait [n ...]
+              Wait  for each specified process and return its termination sta-
+              tus.  Each n may be a process ID or a job  specification;  if  a
+              job  spec  is  given,  all  processes in that job's pipeline are
+              waited for.  If n is not given, all currently active child  pro-
+              cesses  are  waited  for,  and  the return status is zero.  If n
+              specifies a non-existent process or job, the  return  status  is
+.   Otherwise,  the  return  status is the exit status of the
+              last process or job waited for.
+RESTRICTED SHELL
+       If bash is started with the name rbash, or the -r option is supplied at
+       invocation,  the  shell becomes restricted.  A restricted shell is used
+       to set up an environment more controlled than the standard  shell.   It
+       behaves  identically  to bash with the exception that the following are
+       disallowed or not performed:
+       o      changing directories with cd
+       o      setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV
+       o      specifying command names containing /
+       o      specifying  a  file  name containing a / as an argument to the .
+              builtin command
+       o      Specifying a filename containing a slash as an argument  to  the
+              -p option to the hash builtin command
+       o      importing  function  definitions  from  the shell environment at
+              startup
+       o      parsing the value of SHELLOPTS from  the  shell  environment  at
+              startup
+       o      redirecting output using the >, >|, <>, >&, &>, and >> redirect-
+              ion operators
+       o      using the exec builtin command to replace the shell with another
+              command
+       o      adding  or  deleting builtin commands with the -f and -d options
+              to the enable builtin command
+       o      Using the  enable  builtin  command  to  enable  disabled  shell
+              builtins
+       o      specifying the -p option to the command builtin command
+       o      turning off restricted mode with set +r or set +o restricted.
+       These restrictions are enforced after any startup files are read.
+       When a command that is found to be a shell script is executed (see COM-
+       MAND EXECUTION above), rbash turns off any restrictions  in  the  shell
+       spawned to execute the script.
+SEE ALSO
+       Bash Reference Manual, Brian Fox and Chet Ramey
+       The Gnu Readline Library, Brian Fox and Chet Ramey
+       The Gnu History Library, Brian Fox and Chet Ramey
+       Portable  Operating  System  Interface (POSIX) Part 2: Shell and Utili-
+       ties, IEEE
+       sh(1), ksh(1), csh(1)
+       emacs(1), vi(1)
+       readline(3)
+FILES
+       /bin/bash
+              The bash executable
+       /etc/profile
+              The systemwide initialization file, executed for login shells
+       ~/.bash_profile
+              The personal initialization file, executed for login shells
+       ~/.bashrc
+              The individual per-interactive-shell startup file
+       ~/.bash_logout
+              The  individual  login shell cleanup file, executed when a login
+              shell exits
+       ~/.inputrc
+              Individual readline initialization file
+AUTHORS
+       Brian Fox, Free Software Foundation
+       bfox@gnu.org
+       Chet Ramey, Case Western Reserve University
+       chet@po.cwru.edu
+BUG REPORTS
+       If you find a bug in bash, you should report it.  But first, you should
+       make  sure  that  it really is a bug, and that it appears in the latest
+       version  of  bash.   The  latest  version  is  always  available   from
+       ftp://ftp.gnu.org/pub/bash/.
+       Once  you  have  determined that a bug actually exists, use the bashbug
+       command to submit a bug report.  If you have a fix, you are  encouraged
+       to  mail that as well!  Suggestions and `philosophical' bug reports may
+       be mailed  to  bug-bash@gnu.org  or  posted  to  the  Usenet  newsgroup
+       gnu.bash.bug.
+       ALL bug reports should include:
+       The version number of bash
+       The hardware and operating system
+       The compiler used to compile
+       A description of the bug behaviour
+       A short script or `recipe' which exercises the bug
+       bashbug  inserts  the first three items automatically into the template
+       it provides for filing a bug report.
+       Comments and bug reports concerning this manual page should be directed
+       to chet@po.cwru.edu.
+BUGS
+       It's too big and too slow.
+       There are some subtle differences between bash and traditional versions
+       of sh, mostly because of the POSIX specification.
+       Aliases are confusing in some uses.
+       Shell builtin commands and functions are not stoppable/restartable.
+       Compound commands and command sequences of the form `a ; b ; c' are not
+       handled  gracefully  when  process  suspension  is  attempted.   When a
+       process is stopped, the shell immediately executes the next command  in
+       the  sequence.   It  suffices to place the sequence of commands between
+       parentheses to force it into a subshell, which  may  be  stopped  as  a
+       unit.
+       Commands  inside  of  $(...)  command substitution are not parsed until
+       substitution is attempted.  This will delay error reporting until  some
+       time after the command is entered.  For example, unmatched parentheses,
+       even inside shell comments, will result in  error  messages  while  the
+       construct is being read.
+       Array variables may not (yet) be exported.
+GNU Bash-3.2                   2006 September 28                       bash(1)