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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.
       : [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 executed 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 positional 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 supplied, 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 the 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, if jobspec was not found or 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 read-
	      line 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  sup-
	      plied, have the following meanings:
	      -m keymap
		     Use keymap as the keymap to be affected by the subsequent bindings.  Accept-
		     able keymap names are emacs,  emacs-standard,  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 execut-
	      ing a loop when break is executed.

       builtin shell-builtin [arguments]
	      Execute the specified shell builtin, passing it arguments, and return its exit sta-
	      tus.   This  is  useful  when defining a function whose name is the same as a shell
	      builtin, retaining the functionality 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.  Alterna-
	      tive 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  direc-
	      tory  structure  instead of following symbolic links (see also the -P option to the
	      set builtin command); the -L option forces symbolic links to be followed.  An argu-
	      ment  of - is equivalent to $OLDPWD.  The return value is true if the directory was
	      successfully changed; false otherwise.

       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  guaran-
	      teed  to find all of the standard utilities.  If either the -V or -v option is sup-
	      plied, 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 sup-
	      plied and an error occurred or command cannot be found, the  exit  status  is  127.
	      Otherwise, the exit status 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 avail-
	      able, will not have useful values.

	      The  matches  will  be  generated in the same way as if the programmable completion
	      code had generated them directly from a  completion  specification  with	the  same
	      flags.   If  word  is  specified, only those completions matching word will be dis-
	      played.

	      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 pre-
       fix] [-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  sup-
	      plied,  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  specification  for each name, or, if no names are supplied, all comple-
	      tion specifications.

	      The process of applying these completion specifications  when  word  completion  is
	      attempted is described above under Programmable 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 expansion before the complete builtin is invoked.
	      -o comp-option
		      The  comp-option controls several aspects of the compspec's behavior beyond
		      the simple generation of completions.  comp-option may be one of:
		      default Use readline's default filename completion if the  compspec  gener-
			      ates no matches.
		      dirnames
			      Perform  directory  name	completion  if	the compspec generates no
			      matches.
		      filenames
			      Tell readline that the compspec generates filenames, so it can per-
			      form  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 com-
			      pleted at the end of the line.
	      -A action
		      The action may be one of the following to generate a list of possible  com-
		      pletions:
		      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 specified 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 completed.
	      -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 completions 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 generated 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  completion  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 argument, an attempt is made to remove a com-
	      pletion 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.   The  -F  option  implies	-f.  The following options can be used to
	      restrict output to variables with the specified  attribute  or  to  give	variables
	      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 evaluation (see ARITHMETIC
		     EVALUATION ) is performed when the variable is assigned a value.
	      -r     Make names readonly.  These names cannot then be assigned values  by  subse-
		     quent assignment statements or unset.
	      -t     Give each name the trace attribute.  Traced functions inherit the DEBUG trap
		     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 variable.	When used in  a  function,  makes
	      each  name  local,  as  with  the  local	command.  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  assign-
	      ment  syntax  (see  Arrays  above),  one of the names is not a valid shell variable
	      name, an attempt is made to turn off readonly 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, prefixing 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 jobspec 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, interpretation of the following	backslash-escaped  characters  is
	      enabled.	 The  -E  option  disables the interpretation of these escape characters,
	      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 char-
	      acters 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)
	      \nnn   the eight-bit character whose value is the octal value  nnn  (one	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  com-
	      mand 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 com-
	      mand 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 argu-
	      ments are given, or if the -p option is supplied,  a  list  of  shell  builtins  is
	      printed.	 With  no  other option arguments, 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 indication 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 command.  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 beginning of the zeroth arg passed to command.  This  is  what
	      login(1)	does.  The -c option causes command to be executed with an empty environ-
	      ment.  If -a is supplied, the shell passes name as the zeroth argument to the  exe-
	      cuted  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 cannot 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 environment of subse-
	      quently executed commands.  If the -f option is given, the  names  refer	to  func-
	      tions.  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  prop-
	      erty  to	be  removed from the named variables.  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 function.

       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  current  command  num-
	      ber).   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 specified 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.   Otherwise,  the editor given by ename is invoked on a file con-
	      taining 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
	      command.

	      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-executed, 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 specify 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 parameters.  optstring con-
	      tains  the  option  characters  to  be  recognized; 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 argu-
	      ment, getopts places that argument into the variable OPTARG.  The  shell	does  not
	      reset  OPTIND  automatically;  it  must be manually reset between multiple calls to
	      getopts within the same shell invocation if a new set of parameters 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 displayed, 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 sup-
	      plied, 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  format  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 numbers.  Lines listed
	      with a * have been modified.  An argument of n lists only the  last  n  lines.   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 cur-
		     rent 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, overwriting 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.

	      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 following 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  job-
	      spec.   sigspec  is either a signal name such as SIGKILL or a signal number; signum
	      is a signal number.  If sigspec is a signal name, the name may  be  given  with  or
	      without  the  SIG  prefix.  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 ARITHMETIC 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
	      function	and  its  children.  With no operands, local writes a list of local vari-
	      ables to the standard output.  It is an error to use local when not within a  func-
	      tion.   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 following 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 sta-
	      tus is 0.  popd returns false if an invalid option is  encountered,  the	directory
	      stack is empty, a non-existent directory stack entry is specified, or the directory
	      change fails.

       printf format [arguments]
	      Write the formatted arguments to the standard output under the control of the  for-
	      mat.  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 format specifications,
	      each of which causes printing of the next successive argument.  In addition to  the
	      standard	printf(1)  formats, %b causes printf to expand backslash escape sequences
	      in the corresponding argument, and %q causes printf  to  output  the  corresponding
	      argument in a format that can be reused as shell input.

	      The  format  is reused as necessary to consume all of the arguments.  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  work-
		     ing 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 directory stack is empty, a non-existent directory stack ele-
	      ment 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 inter-
	      vening 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 following 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  com-
		     plete line of input.
	      -p prompt
		     Display  prompt  on  standard  error,  without  a	trailing  newline, before
		     attempting to read any input.  The prompt is displayed only if input is com-
		     ing from a terminal.
	      -r     Backslash	does not act as an escape character.  The backslash is considered
		     to be part of the line.  In particular, a backslash-newline pair may not  be
		     used as a line continuation.
	      -s     Silent mode.  If input is coming from a terminal, characters 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 read-
		     ing 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 variable 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 ...]
	      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  correspond-
	      ing  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.  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)  com-
	      mand,  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.

       set [--abefhkmnptuvxBCHP] [-o option] [arg ...]
	      Without options, the name and value of each shell variable are displayed in a  for-
	      mat  that  can  be  reused as input.  The output is sorted according to the current
	      locale.  When options are specified, they set or unset shell attributes.	Any argu-
	      ments remaining after the options are processed are treated as values for the posi-
	      tional parameters and are assigned, in order, to $1,  $2,  ...   $n.   Options,  if
	      specified, have the following 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  immediately,  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 an until or while loop, part of 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 envi-
		      ronment 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 processes run in a separate process group and a line  containing
		      their exit status is printed upon their completion.
	      -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 interface.  This is enabled
			      by  default  when  the  shell  is  interactive, unless the shell is
			      started with the --noediting option.
		      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 interactive 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.
		      posix   Change the behavior of bash where  the  default  operation  differs
			      from the POSIX 1003.2 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  com-
		      mands  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 parameter expansion.   If
		      expansion is attempted on an unset variable, the shell prints an error mes-
		      sage, 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, display the	expanded  value  of  PS4,
		      followed by the command and its expanded arguments.
	      -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 <> re-
		      direction  operators.  This may be overridden when creating output files by
		      using the redirection operator >| instead of >.
	      -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.
	      --      If no arguments follow this option,  then  the  positional  parameters  are
		      unset.   Otherwise,  the positional parameters 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 positional 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 argu-
	      ments 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 encountered.

       shift [n]
	      The  positional  parameters  from n+1 ... are renamed to $1 ....	Parameters repre-
	      sented 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  behavior.	 With  no
	      options,	or  with the -p option, a list of all settable 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 following
	      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  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  display  is  limited  to
	      those  options  which  are set or unset, respectively.  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 component in a cd  com-
		      mand  will be corrected.	The errors checked for are transposed characters,
		      a missing character, and one character too many.	If a correction is found,
		      the  corrected file name is printed, and the command proceeds.  This option
		      is only used by interactive shells.
	      checkhash
		      If set, bash checks that a command found in the hash  table  exists  before
		      trying  to execute it.  If a hashed command no longer exists, a normal path
		      search is performed.
	      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 cannot 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 interactive shells.
	      extglob If set, the extended pattern matching features described above under  Path-
		      name Expansion are enabled.
	      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 history substitution are
		      not immediately passed to the shell parser.  Instead, the resulting line is
		      loaded into the readline editing buffer, allowing further modification.
	      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 interactive 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  INVOCA-
		      TION 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 displayed.
	      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 perform-
		      ing pathname expansion (see Pathname Expansion above).
	      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 Programmable Completion
		      above) are enabled.  This option is enabled by default.
	      promptvars
		      If set, prompt strings undergo variable and parameter expansion 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 discover
		      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 parameters.
	      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 com-
	      posed of the primaries described above under CONDITIONAL EXPRESSIONS.

	      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  prece-
		     dence 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 num-
	      ber 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 argument 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 con-
		     ditional 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  evaluated  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 or -, all specified signals are reset to their original
	      values (the values they 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 num-
	      ber.   Each sigspec is either a signal name defined in <signal.h>, or a signal num-
	      ber.  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 after every simple command (see
	      SHELL GRAMMAR above).  If a sigspec is ERR, the command arg is executed whenever	a
	      simple  command  has  a  non-zero exit status.  The ERR trap is not executed if the
	      failed command is part of an until or while loop, part of an if statement, part  of
	      a  && or || list, or if the command's return value is being inverted via !.  The -l
	      option causes the shell to print a list of signal  names	and  their  corresponding
	      numbers.	 Signals  ignored  upon  entry	to  the shell cannot be trapped or reset.
	      Trapped signals 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, key-
	      word, function, builtin, or file if name is an alias, shell  reserved  word,  func-
	      tion,  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
	      specified 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
	      function	lookup,  as  with  the	command builtin.  type returns true if any of the
	      arguments are found, false if none are found.

       ulimit [-SHacdflmnpstuv [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 cur-
	      rent 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 follows:
	      -a     All current limits are reported
	      -c     The maximum size of core files created
	      -d     The maximum size of a process's data segment
	      -f     The maximum size of files created by the shell
	      -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)
	      -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

	      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 symbolic form; the
	      default output is an octal number.  If the -p option is supplied, and mode is omit-
	      ted,  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 specifed, each name refers to a shell
	      function, and the function definition is removed.  Each unset variable or  function
	      is  removed  from the environment passed to subsequent 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 status is true
	      unless a name does not exist or is readonly.

       wait [n]
	      Wait for the specified process and return its  termination  status.   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-exis-
	      tent 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-2.05a				 2001 November 27			 BASH_BUILTINS(1)
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