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BASH_BUILTINS(1)					      BASH_BUILTINS(1)



NAME
       bash,  :,  ., [, alias, bg, bind, break, builtin, cd, command, compgen,
       complete, continue, declare, dirs, disown, echo,	 enable,  eval,	 exec,
       exit,  export,  fc,  fg, getopts, hash, help, history, jobs, kill, let,
       local, logout, popd, printf, pushd, pwd, read, readonly,	 return,  set,
       shift,  shopt,  source,	suspend,  test,	 times,	 trap,	type, typeset,
       ulimit, umask, unalias, unset,  wait  -	bash  built-in	commands,  see
       bash(1)

BASH 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.	Also, please note that while executing in non-interac-
       tive  mode  and	while  in  posix mode, any special builtin (like ., :,
       break, continue, eval,  exec,  exit,  export,  readonly,	 return,  set,
       shift,  source,	times,	trap,  unset)  exiting	with a non-zero status
       causes the shell to stop execution.
       : [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.

	      Note  aliases  are  not  expanded	 by default in non-interactive
	      shell, and it can be enabled by setting the expand_aliases shell
	      option using shopt.

       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  non-zero when n is <= 0; Otherwise, break
	      returns 0 value.

       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.	 When continue is executed inside of loop, the
	      return  value  is	 non-zero  when	 n is <= 0; Otherwise, continue
	      returns 0 value.	When continue is executed outside of loop, the
	      return value is 0.

       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
	      0 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, is used.  When editing is  complete,
	      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
	      1	 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
	      1; 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
	      function.

       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
		     multiple optname arguments are given with -q, the	return
		     status is zero if all optnames are enabled; non-zero oth-
		     erwise.
	      -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
		      COLUMNS.
	      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:
		      1.     The -F option to the declare builtin displays the
			     source file name and line number corresponding to
			     each function name supplied as an argument.
		      2.     If	 the  command  run by the DEBUG trap returns a
			     non-zero value, the next command is  skipped  and
			     not executed.
		      3.     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.
		      4.     BASH_ARGC	and BASH_ARGV are updated as described
			     in their descriptions above.
		      5.     Function tracing is enabled:   command  substitu-
			     tion, shell functions, and subshells invoked with
			     ( command ) inherit the DEBUG and RETURN traps.
		      6.     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.  When the suspended shell is a  background  process,  it
	      can  be  restarted by the fg command. For more information, read
	      the JOB CONTROL section. The suspend command can not suspend the
	      login shell.  However, when -f option is specified, suspend com-
	      mand can suspend even login  shell.   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.

	      0 arguments
		     The expression is false.
	      1 argument
		     The expression is true if and only if the argument is not
		     null.
	      2 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.
	      3 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.
	      4 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.
	      5 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, reset or listed.  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 (has no effect on Linux)
	      -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
	      0 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
	      127.   Otherwise,	 the  return  status is the exit status of the
	      last process or job waited for.

SEE ALSO
       bash(1), sh(1)



GNU Bash-3.0			  2004 Apr 20		      BASH_BUILTINS(1)
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