Bash-4.2 distribution sources and documentation

[thirdparty/bash.git] / doc / builtins.0

BASH_BUILTINS(1)                                              BASH_BUILTINS(1)



N\bNA\bAM\bME\bE
       bash,  :,  .,  [, alias, bg, bind, break, builtin, caller, cd, command,
       compgen, complete, compopt,  continue,  declare,  dirs,  disown,  echo,
       enable,  eval,  exec, exit, export, false, fc, fg, getopts, hash, help,
       history, jobs, kill, let, local, logout, mapfile, popd, printf,  pushd,
       pwd,  read, readonly, return, set, shift, shopt, source, suspend, test,
       times, trap, true, type, typeset, ulimit, umask, unalias, unset, wait -
       bash built-in commands, see b\bba\bas\bsh\bh(1)

B\bBA\bAS\bSH\bH B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
       Unless otherwise noted, each builtin command documented in this section
       as accepting options preceded by -\b- accepts -\b--\b- to signify the end of the
       options.   The  :\b:, t\btr\bru\bue\be, f\bfa\bal\bls\bse\be, and t\bte\bes\bst\bt builtins do not accept options
       and do not treat -\b--\b- specially.  The e\bex\bxi\bit\bt, l\blo\bog\bgo\bou\but\bt, b\bbr\bre\bea\bak\bk, c\bco\bon\bnt\bti\bin\bnu\bue\be, l\ble\bet\bt,
       and  s\bsh\bhi\bif\bft\bt builtins accept and process arguments beginning with -\b- with-
       out requiring -\b--\b-.  Other builtins that accept  arguments  but  are  not
       specified  as accepting options interpret arguments beginning with -\b- as
       invalid options and require -\b--\b- to prevent this interpretation.
       :\b: [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
              No effect; the command does nothing beyond  expanding  _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
              and  performing any specified redirections.  A zero exit code is
              returned.

        .\b.  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
       s\bso\bou\bur\brc\bce\be _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
              Read and execute commands from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  in  the  current  shell
              environment  and return the exit status of the last command exe-
              cuted from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be.  If _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be does not contain a slash, file
              names  in  P\bPA\bAT\bTH\bH  are used to find the directory containing _\bf_\bi_\bl_\be_\b-
              _\bn_\ba_\bm_\be.  The file searched for in P\bPA\bAT\bTH\bH  need  not  be  executable.
              When  b\bba\bas\bsh\bh  is  not  in  _\bp_\bo_\bs_\bi_\bx  _\bm_\bo_\bd_\be,  the  current directory is
              searched if no file is found in P\bPA\bAT\bTH\bH.  If the s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh  option
              to  the  s\bsh\bho\bop\bpt\bt  builtin  command  is turned off, the P\bPA\bAT\bTH\bH is not
              searched.  If any _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs are supplied, they become the  posi-
              tional  parameters  when  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  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 _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is  not  found  or
              cannot be read.

       a\bal\bli\bia\bas\bs [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
              A\bAl\bli\bia\bas\bs with no arguments or with the -\b-p\bp option prints the list of
              aliases in the form a\bal\bli\bia\bas\bs _\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be on standard  output.   When
              arguments  are supplied, an alias is defined for each _\bn_\ba_\bm_\be whose
              _\bv_\ba_\bl_\bu_\be is given.  A trailing space in  _\bv_\ba_\bl_\bu_\be causes the next word
              to be checked for alias substitution when the alias is expanded.
              For each _\bn_\ba_\bm_\be in the argument list for which no  _\bv_\ba_\bl_\bu_\be  is  sup-
              plied,  the  name  and  value  of  the  alias is printed.  A\bAl\bli\bia\bas\bs
              returns true unless a _\bn_\ba_\bm_\be is given for which no alias has  been
              defined.

       b\bbg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc ...]
              Resume  each  suspended  job _\bj_\bo_\bb_\bs_\bp_\be_\bc in the background, as if it
              had been started with &\b&.  If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's
              notion  of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used.  b\bbg\bg _\bj_\bo_\bb_\bs_\bp_\be_\bc returns 0 unless
              run when job control is disabled or, when run with  job  control
              enabled,  any  specified  _\bj_\bo_\bb_\bs_\bp_\be_\bc  was  not found or was started
              without job control.

       b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] [-\b-l\blp\bps\bsv\bvP\bPS\bSV\bV]
       b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] [-\b-q\bq _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn] [-\b-u\bu _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn] [-\b-r\br _\bk_\be_\by_\bs_\be_\bq]
       b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] -\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
       b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] -\b-x\bx _\bk_\be_\by_\bs_\be_\bq:_\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
       b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] _\bk_\be_\by_\bs_\be_\bq:_\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
       b\bbi\bin\bnd\bd _\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
              Display current r\bre\bea\bad\bdl\bli\bin\bne\be key and function bindings, bind  a  key
              sequence  to  a  r\bre\bea\bad\bdl\bli\bin\bne\be  function  or macro, or set a r\bre\bea\bad\bdl\bli\bin\bne\be
              variable.  Each non-option argument is a  command  as  it  would
              appear  in  _\b._\bi_\bn_\bp_\bu_\bt_\br_\bc, 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:
              -\b-m\bm _\bk_\be_\by_\bm_\ba_\bp
                     Use _\bk_\be_\by_\bm_\ba_\bp as the keymap to be affected by the subsequent
                     bindings.  Acceptable _\bk_\be_\by_\bm_\ba_\bp names are _\be_\bm_\ba_\bc_\bs_\b, _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\b-
                     _\bd_\ba_\br_\bd_\b,  _\be_\bm_\ba_\bc_\bs_\b-_\bm_\be_\bt_\ba_\b,  _\be_\bm_\ba_\bc_\bs_\b-_\bc_\bt_\bl_\bx_\b,  _\bv_\bi_\b, _\bv_\bi_\b-_\bm_\bo_\bv_\be_\b, _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd,
                     and _\bv_\bi_\b-_\bi_\bn_\bs_\be_\br_\bt.  _\bv_\bi is equivalent to _\bv_\bi_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd; _\be_\bm_\ba_\bc_\bs  is
                     equivalent to _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\bd_\ba_\br_\bd.
              -\b-l\bl     List the names of all r\bre\bea\bad\bdl\bli\bin\bne\be functions.
              -\b-p\bp     Display  r\bre\bea\bad\bdl\bli\bin\bne\be  function  names and bindings in such a
                     way that they can be re-read.
              -\b-P\bP     List current r\bre\bea\bad\bdl\bli\bin\bne\be function names and bindings.
              -\b-s\bs     Display r\bre\bea\bad\bdl\bli\bin\bne\be key sequences bound to  macros  and  the
                     strings  they  output  in such a way that they can be re-
                     read.
              -\b-S\bS     Display r\bre\bea\bad\bdl\bli\bin\bne\be key sequences bound to  macros  and  the
                     strings they output.
              -\b-v\bv     Display  r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values in such a way
                     that they can be re-read.
              -\b-V\bV     List current r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values.
              -\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
                     Read key bindings from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be.
              -\b-q\bq _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
                     Query about which keys invoke the named _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn.
              -\b-u\bu _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
                     Unbind all keys bound to the named _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn.
              -\b-r\br _\bk_\be_\by_\bs_\be_\bq
                     Remove any current binding for _\bk_\be_\by_\bs_\be_\bq.
              -\b-x\bx _\bk_\be_\by_\bs_\be_\bq:\b:_\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
                     Cause _\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd to be  executed  whenever  _\bk_\be_\by_\bs_\be_\bq  is
                     entered.   When _\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed, the shell sets
                     the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_L\bLI\bIN\bNE\bE variable to the contents of  the  r\bre\bea\bad\bd-\b-
                     l\bli\bin\bne\be  line  buffer and the R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT variable to the
                     current location of the insertion point.  If the executed
                     command  changes  the  value  of  R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE_\b_L\bLI\bIN\bNE\bE  or R\bRE\bEA\bAD\bD-\b-
                     L\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT, those new values will  be  reflected  in  the
                     editing state.

              The  return value is 0 unless an unrecognized option is given or
              an error occurred.

       b\bbr\bre\bea\bak\bk [_\bn]
              Exit from within a f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or s\bse\bel\ble\bec\bct\bt loop.  If  _\bn  is
              specified,  break  _\bn  levels.   _\bn must be >= 1.  If _\bn is greater
              than the number of enclosing  loops,  all  enclosing  loops  are
              exited.   The  return value is 0 unless _\bn is not greater than or
              equal to 1.

       b\bbu\bui\bil\blt\bti\bin\bn _\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
              Execute the specified shell builtin, passing it  _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs,  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 c\bcd\bd builtin is
              commonly redefined this way.  The  return  status  is  false  if
              _\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn is not a shell builtin command.

       c\bca\bal\bll\ble\ber\br [_\be_\bx_\bp_\br]
              Returns the context of any active subroutine call (a shell func-
              tion or a script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins).  With-
              out _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number and source filename of
              the current subroutine call.  If a non-negative integer is  sup-
              plied as _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br 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 _\be_\bx_\bp_\br does not correspond to a valid position  in
              the call stack.

       c\bcd\bd [-\b-L\bL|[-\b-P\bP [-\b-e\be]]] [_\bd_\bi_\br]
              Change  the  current directory to _\bd_\bi_\br.  The variable H\bHO\bOM\bME\bE is the
              default _\bd_\bi_\br.  The variable C\bCD\bDP\bPA\bAT\bTH\bH defines the  search  path  for
              the  directory  containing  _\bd_\bi_\br.  Alternative directory names in
              C\bCD\bDP\bPA\bAT\bTH\bH are separated by a colon (:).  A null directory  name  in
              C\bCD\bDP\bPA\bAT\bTH\bH  is  the  same as the current directory, i.e., ``.\b.''.  If
              _\bd_\bi_\br begins with a slash (/), then C\bCD\bDP\bPA\bAT\bTH\bH is  not  used.  The  -\b-P\bP
              option  says  to use the physical directory structure instead of
              following symbolic links (see also the  -\b-P\bP  option  to  the  s\bse\bet\bt
              builtin command); the -\b-L\bL option forces symbolic links to be fol-
              lowed.  If the -\b-e\be option is supplied with -\b-P\bP,  and  the  current
              working directory cannot be successfully determined after a suc-
              cessful directory change, c\bcd\bd will return an unsuccessful status.
              An  argument  of  -\b-  is  equivalent  to $\b$O\bOL\bLD\bDP\bPW\bWD\bD.  If a non-empty
              directory name from C\bCD\bDP\bPA\bAT\bTH\bH is used, or if -\b- is the  first  argu-
              ment, and the directory change is successful, the absolute path-
              name 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.

       c\bco\bom\bmm\bma\ban\bnd\bd [-\b-p\bpV\bVv\bv] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\ba_\br_\bg ...]
              Run _\bc_\bo_\bm_\bm_\ba_\bn_\bd with _\ba_\br_\bg_\bs  suppressing  the  normal  shell  function
              lookup.  Only builtin commands or commands found in the P\bPA\bAT\bTH\bH are
              executed.  If the -\b-p\bp option is given, the search for _\bc_\bo_\bm_\bm_\ba_\bn_\bd  is
              performed  using  a default value for P\bPA\bAT\bTH\bH that is guaranteed to
              find all of the standard utilities.  If  either  the  -\b-V\bV  or  -\b-v\bv
              option is supplied, a description of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is printed.  The -\b-v\bv
              option causes a single word indicating the command or file  name
              used to invoke _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be displayed; the -\b-V\bV option produces a
              more verbose description.  If the -\b-V\bV or -\b-v\bv option  is  supplied,
              the  exit  status  is  0 if _\bc_\bo_\bm_\bm_\ba_\bn_\bd was found, and 1 if not.  If
              neither option is supplied and an error occurred or _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
              not  be found, the exit status is 127.  Otherwise, the exit sta-
              tus of the c\bco\bom\bmm\bma\ban\bnd\bd builtin is the exit status of _\bc_\bo_\bm_\bm_\ba_\bn_\bd.

       c\bco\bom\bmp\bpg\bge\ben\bn [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bw_\bo_\br_\bd]
              Generate possible completion matches for _\bw_\bo_\br_\bd according  to  the
              _\bo_\bp_\bt_\bi_\bo_\bns,  which  may  be  any  option  accepted  by the c\bco\bom\bmp\bpl\ble\bet\bte\be
              builtin with the exception of -\b-p\bp and -\b-r\br, and write  the  matches
              to  the  standard  output.  When using the -\b-F\bF or -\b-C\bC 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 _\bw_\bo_\br_\bd is speci-
              fied, only those completions matching _\bw_\bo_\br_\bd will be displayed.

              The return value is true unless an invalid option  is  supplied,
              or no matches were generated.

       c\bco\bom\bmp\bpl\ble\bet\bte\be  [-\b-a\bab\bbc\bcd\bde\bef\bfg\bgj\bjk\bks\bsu\buv\bv]  [-\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bE] [-\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn] [-\b-G\bG _\bg_\bl_\bo_\bb_\b-
       _\bp_\ba_\bt] [-\b-W\bW _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt] [-\b-F\bF _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn] [-\b-C\bC _\bc_\bo_\bm_\bm_\ba_\bn_\bd]
              [-\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt] [-\b-P\bP _\bp_\br_\be_\bf_\bi_\bx] [-\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be _\b._\b._\b.]
       c\bco\bom\bmp\bpl\ble\bet\bte\be -\b-p\bpr\br [-\b-D\bDE\bE] [_\bn_\ba_\bm_\be ...]
              Specify  how arguments to each _\bn_\ba_\bm_\be should be completed.  If the
              -\b-p\bp 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 -\b-r\br option removes a completion spec-
              ification  for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are supplied, all com-
              pletion  specifications.   The  -\b-D\bD  option  indicates  that  the
              remaining  options  and  actions should apply to the ``default''
              command completion; that is, completion attempted on  a  command
              for  which  no  completion  has previously been defined.  The -\b-E\bE
              option indicates that the remaining options and  actions  should
              apply  to  ``empty''  command  completion;  that  is, completion
              attempted on a blank line.

              The process of applying  these  completion  specifications  when
              word  completion  is  attempted  is  described  above under P\bPr\bro\bo-\b-
              g\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn.

              Other options, if specified, have the following  meanings.   The
              arguments  to the -\b-G\bG, -\b-W\bW, and -\b-X\bX options (and, if necessary, the
              -\b-P\bP and -\b-S\bS options) should be quoted to protect them from  expan-
              sion before the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin is invoked.
              -\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn
                      The  _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn  controls  several aspects of the comp-
                      spec's behavior beyond the simple generation of  comple-
                      tions.  _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn may be one of:
                      b\bba\bas\bsh\bhd\bde\bef\bfa\bau\bul\blt\bt
                              Perform the rest of the default b\bba\bas\bsh\bh completions
                              if the compspec generates no matches.
                      d\bde\bef\bfa\bau\bul\blt\bt Use readline's default  filename  completion  if
                              the compspec generates no matches.
                      d\bdi\bir\brn\bna\bam\bme\bes\bs
                              Perform  directory  name completion if the comp-
                              spec generates no matches.
                      f\bfi\bil\ble\ben\bna\bam\bme\bes\bs
                              Tell readline that the compspec generates  file-
                              names,  so  it can perform any filename-specific
                              processing (like adding  a  slash  to  directory
                              names,  quoting special characters, or suppress-
                              ing trailing spaces).  Intended to be used  with
                              shell functions.
                      n\bno\bos\bsp\bpa\bac\bce\be Tell   readline  not  to  append  a  space  (the
                              default) to words completed at the  end  of  the
                              line.
                      p\bpl\blu\bus\bsd\bdi\bir\brs\bs
                              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.
              -\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn
                      The _\ba_\bc_\bt_\bi_\bo_\bn may be one of the  following  to  generate  a
                      list of possible completions:
                      a\bal\bli\bia\bas\bs   Alias names.  May also be specified as -\b-a\ba.
                      a\bar\brr\bra\bay\byv\bva\bar\br
                              Array variable names.
                      b\bbi\bin\bnd\bdi\bin\bng\bg R\bRe\bea\bad\bdl\bli\bin\bne\be key binding names.
                      b\bbu\bui\bil\blt\bti\bin\bn Names  of  shell  builtin commands.  May also be
                              specified as -\b-b\bb.
                      c\bco\bom\bmm\bma\ban\bnd\bd Command names.  May also be specified as -\b-c\bc.
                      d\bdi\bir\bre\bec\bct\bto\bor\bry\by
                              Directory names.  May also be specified as -\b-d\bd.
                      d\bdi\bis\bsa\bab\bbl\ble\bed\bd
                              Names of disabled shell builtins.
                      e\ben\bna\bab\bbl\ble\bed\bd Names of enabled shell builtins.
                      e\bex\bxp\bpo\bor\brt\bt  Names of exported shell variables.  May also  be
                              specified as -\b-e\be.
                      f\bfi\bil\ble\be    File names.  May also be specified as -\b-f\bf.
                      f\bfu\bun\bnc\bct\bti\bio\bon\bn
                              Names of shell functions.
                      g\bgr\bro\bou\bup\bp   Group names.  May also be specified as -\b-g\bg.
                      h\bhe\bel\blp\bpt\bto\bop\bpi\bic\bc
                              Help topics as accepted by the h\bhe\bel\blp\bp builtin.
                      h\bho\bos\bst\btn\bna\bam\bme\be
                              Hostnames,  as  taken from the file specified by
                              the H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE shell variable.
                      j\bjo\bob\bb     Job names, if job control is active.   May  also
                              be specified as -\b-j\bj.
                      k\bke\bey\byw\bwo\bor\brd\bd Shell  reserved words.  May also be specified as
                              -\b-k\bk.
                      r\bru\bun\bnn\bni\bin\bng\bg Names of running jobs, if job control is active.
                      s\bse\ber\brv\bvi\bic\bce\be Service names.  May also be specified as -\b-s\bs.
                      s\bse\bet\bto\bop\bpt\bt  Valid  arguments  for  the  -\b-o\bo option to the s\bse\bet\bt
                              builtin.
                      s\bsh\bho\bop\bpt\bt   Shell option names  as  accepted  by  the  s\bsh\bho\bop\bpt\bt
                              builtin.
                      s\bsi\big\bgn\bna\bal\bl  Signal names.
                      s\bst\bto\bop\bpp\bpe\bed\bd Names of stopped jobs, if job control is active.
                      u\bus\bse\ber\br    User names.  May also be specified as -\b-u\bu.
                      v\bva\bar\bri\bia\bab\bbl\ble\be
                              Names of all shell variables.  May also be spec-
                              ified as -\b-v\bv.
              -\b-C\bC _\bc_\bo_\bm_\bm_\ba_\bn_\bd
                      _\bc_\bo_\bm_\bm_\ba_\bn_\bd  is  executed in a subshell environment, and its
                      output is used as the possible completions.
              -\b-F\bF _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
                      The shell function _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn is executed in  the  current
                      shell  environment.  When it finishes, the possible com-
                      pletions are retrieved from the value of  the  C\bCO\bOM\bMP\bPR\bRE\bEP\bPL\bLY\bY
                      array variable.
              -\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt
                      The  pathname  expansion  pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
                      generate the possible completions.
              -\b-P\bP _\bp_\br_\be_\bf_\bi_\bx
                      _\bp_\br_\be_\bf_\bi_\bx is added at the beginning of each  possible  com-
                      pletion after all other options have been applied.
              -\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx
                      _\bs_\bu_\bf_\bf_\bi_\bx is appended to each possible completion after all
                      other options have been applied.
              -\b-W\bW _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt
                      The _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt is split using the characters  in  the  I\bIF\bFS\bS
                      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.
              -\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt
                      _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for  pathname  expansion.
                      It is applied to the list of possible completions gener-
                      ated by the preceding options and  arguments,  and  each
                      completion  matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed from the list.
                      A leading !\b! in _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt negates the  pattern;  in  this
                      case,  any completion not matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed.

              The return value is true unless an invalid option  is  supplied,
              an  option  other than -\b-p\bp or -\b-r\br is supplied without a _\bn_\ba_\bm_\be argu-
              ment, an attempt is made to remove  a  completion  specification
              for a _\bn_\ba_\bm_\be for which no specification exists, or an error occurs
              adding a completion specification.

       c\bco\bom\bmp\bpo\bop\bpt\bt [-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bE] [+\b+o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be]
              Modify  completion  options  for  each  _\bn_\ba_\bm_\be  according  to  the
              _\bo_\bp_\bt_\bi_\bo_\bns,  or  for the currently-executing completion if no _\bn_\ba_\bm_\bes
              are supplied.  If no _\bo_\bp_\bt_\bi_\bo_\bns are given, display  the  completion
              options  for  each _\bn_\ba_\bm_\be or the current completion.  The possible
              values of _\bo_\bp_\bt_\bi_\bo_\bn  are  those  valid  for  the  c\bco\bom\bmp\bpl\ble\bet\bte\be  builtin
              described  above.   The  -\b-D\bD  option indicates that the remaining
              options should apply to the ``default'' command completion; that
              is,  completion  attempted  on a command for which no completion
              has previously been defined.  The -\b-E\bE option indicates  that  the
              remaining  options should apply to ``empty'' command completion;
              that is, completion attempted on a blank line.

              The return value is true unless an invalid option  is  supplied,
              an attempt is made to modify the options for a _\bn_\ba_\bm_\be for which no
              completion specification exists, or an output error occurs.

       c\bco\bon\bnt\bti\bin\bnu\bue\be [_\bn]
              Resume the next iteration of the enclosing f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or
              s\bse\bel\ble\bec\bct\bt  loop.   If  _\bn  is specified, resume at the _\bnth enclosing
              loop.  _\bn must be >= 1.  If _\bn  is  greater  than  the  number  of
              enclosing  loops,  the  last  enclosing  loop (the ``top-level''
              loop) is resumed.  The return value is 0 unless _\bn is not greater
              than or equal to 1.

       d\bde\bec\bcl\bla\bar\bre\be [-\b-a\baA\bAf\bfF\bFg\bgi\bil\blr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
       t\bty\byp\bpe\bes\bse\bet\bt [-\b-a\baA\bAf\bfF\bFg\bgi\bil\blr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
              Declare  variables and/or give them attributes.  If no _\bn_\ba_\bm_\bes are
              given then display the values of variables.  The -\b-p\bp option  will
              display the attributes and values of each _\bn_\ba_\bm_\be.  When -\b-p\bp is used
              with _\bn_\ba_\bm_\be arguments, additional options are ignored.  When -\b-p\bp is
              supplied  without _\bn_\ba_\bm_\be arguments, it will display the attributes
              and values of all variables having the attributes  specified  by
              the  additional  options.  If no other options are supplied with
              -\b-p\bp, d\bde\bec\bcl\bla\bar\bre\be will display the attributes and values of all  shell
              variables.   The  -\b-f\bf  option  will restrict the display to shell
              functions.  The -\b-F\bF option inhibits the display of function defi-
              nitions;  only the function name and attributes are printed.  If
              the e\bex\bxt\btd\bde\beb\bbu\bug\bg shell option is enabled  using  s\bsh\bho\bop\bpt\bt,  the  source
              file name and line number where the function is defined are dis-
              played as well.  The -\b-F\bF option implies -\b-f\bf.  The -\b-g\bg option forces
              variables  to  be  created or modified at the global scope, even
              when d\bde\bec\bcl\bla\bar\bre\be is executed in a shell function.  It is ignored  in
              all  other cases.  The following options can be used to restrict
              output to variables with the  specified  attribute  or  to  give
              variables attributes:
              -\b-a\ba     Each  _\bn_\ba_\bm_\be  is  an  indexed  array  variable  (see A\bAr\brr\bra\bay\bys\bs
                     above).
              -\b-A\bA     Each _\bn_\ba_\bm_\be is an associative array  variable  (see  A\bAr\brr\bra\bay\bys\bs
                     above).
              -\b-f\bf     Use function names only.
              -\b-i\bi     The variable is treated as an integer; arithmetic evalua-
                     tion (see A\bAR\bRI\bIT\bTH\bHM\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN above) is performed  when
                     the variable is assigned a value.
              -\b-l\bl     When  the  variable  is  assigned a value, all upper-case
                     characters are converted to lower-case.   The  upper-case
                     attribute is disabled.
              -\b-r\br     Make _\bn_\ba_\bm_\bes readonly.  These names cannot then be assigned
                     values by subsequent assignment statements or unset.
              -\b-t\bt     Give each _\bn_\ba_\bm_\be the  _\bt_\br_\ba_\bc_\be  attribute.   Traced  functions
                     inherit  the  D\bDE\bEB\bBU\bUG\bG  and  R\bRE\bET\bTU\bUR\bRN\bN  traps  from the calling
                     shell.  The trace attribute has no  special  meaning  for
                     variables.
              -\b-u\bu     When  the  variable  is  assigned a value, all lower-case
                     characters are converted to upper-case.   The  lower-case
                     attribute is disabled.
              -\b-x\bx     Mark  _\bn_\ba_\bm_\bes  for  export  to  subsequent commands via the
                     environment.

              Using `+' instead of `-' turns off the attribute  instead,  with
              the exceptions that +\b+a\ba may not be used to destroy an array vari-
              able and +\b+r\br will not remove the readonly attribute.   When  used
              in a function, makes each _\bn_\ba_\bm_\be local, as with the l\blo\boc\bca\bal\bl command,
              unless the -\b-g\bgP\bP o\bop\bpt\bti\bio\bon\bn i\bis\bs s\bsu\bup\bpp\bpl\bli\bie\bed\bd,\b, I\bIf\bf a\ba v\bva\bar\bri\bia\bab\bbl\ble\be  n\bna\bam\bme\be  i\bis\bs  f\bfo\bol\bl-\b-
              l\blo\bow\bwe\bed\bd b\bby\by =\b=_\bv_\ba_\bl_\bu_\be,\b, t\bth\bhe\be v\bva\bal\blu\bue\be o\bof\bf t\bth\bhe\be v\bva\bar\bri\bia\bab\bbl\ble\be i\bis\bs s\bse\bet\bt t\bto\bo _\bv_\ba_\bl_\bu_\be.\b.  T\bTh\bhe\be
              r\bre\bet\btu\bur\brn\bn v\bva\bal\blu\bue\be i\bis\bs 0\b0 u\bun\bnl\ble\bes\bss\bs a\ban\bn i\bin\bnv\bva\bal\bli\bid\bd o\bop\bpt\bti\bio\bon\bn  i\bis\bs  e\ben\bnc\bco\bou\bun\bnt\bte\ber\bre\bed\bd,\b,  a\ban\bn
              a\bat\btt\bte\bem\bmp\bpt\bt  i\bis\bs  m\bma\bad\bde\be  t\bto\bo d\bde\bef\bfi\bin\bne\be a\ba f\bfu\bun\bnc\bct\bti\bio\bon\bn u\bus\bsi\bin\bng\bg `\b``\b`-\b-f\bf f\bfo\boo\bo=\b=b\bba\bar\br'\b''\b',\b, a\ban\bn
              a\bat\btt\bte\bem\bmp\bpt\bt i\bis\bs m\bma\bad\bde\be t\bto\bo a\bas\bss\bsi\big\bgn\bn a\ba v\bva\bal\blu\bue\be t\bto\bo  a\ba  r\bre\bea\bad\bdo\bon\bnl\bly\by  v\bva\bar\bri\bia\bab\bbl\ble\be,\b,  a\ban\bn
              a\bat\btt\bte\bem\bmp\bpt\bt  i\bis\bs  m\bma\bad\bde\be t\bto\bo a\bas\bss\bsi\big\bgn\bn a\ba v\bva\bal\blu\bue\be t\bto\bo a\ban\bn a\bar\brr\bra\bay\by v\bva\bar\bri\bia\bab\bbl\ble\be w\bwi\bit\bth\bho\bou\but\bt
              u\bus\bsi\bin\bng\bg t\bth\bhe\be c\bco\bom\bmp\bpo\bou\bun\bnd\bd a\bas\bss\bsi\big\bgn\bnm\bme\ben\bnt\bt s\bsy\byn\bnt\bta\bax\bx (\b(s\bse\bee\be A\bAr\brr\bra\bay\bys\bs above), one  of
              the _\bn_\ba_\bm_\be_\bs 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 -\b-f\bf.

       d\bdi\bir\brs\bs [\b[+\b+_\bn]\b] [\b[-\b-_\bn]\b] [\b[-\b-c\bcl\blp\bpv\bv]\b]
              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  p\bpu\bus\bsh\bhd\bd  command;  the  p\bpo\bop\bpd\bd command removes
              entries from the list.
              +\b+_\bn     Displays the _\bnth entry counting from the left of the list
                     shown by d\bdi\bir\brs\bs when invoked without options, starting with
                     zero.
              -\b-_\bn     Displays the _\bnth entry counting from  the  right  of  the
                     list shown by d\bdi\bir\brs\bs when invoked without options, starting
                     with zero.
              -\b-c\bc     Clears  the  directory  stack  by  deleting  all  of  the
                     entries.
              -\b-l\bl     Produces  a  longer  listing;  the default listing format
                     uses a tilde to denote the home directory.
              -\b-p\bp     Print the directory stack with one entry per line.
              -\b-v\bv     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 _\bn
              indexes beyond the end of the directory stack.

       d\bdi\bis\bso\bow\bwn\bn [-\b-a\bar\br] [-\b-h\bh] [_\bj_\bo_\bb_\bs_\bp_\be_\bc ...]
              Without options, each _\bj_\bo_\bb_\bs_\bp_\be_\bc  is  removed  from  the  table  of
              active  jobs.   If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, and neither -\b-a\ba nor -\b-r\br
              is supplied, the shell's notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used.   If
              the -\b-h\bh option is given, each _\bj_\bo_\bb_\bs_\bp_\be_\bc is not removed from the ta-
              ble, but is marked so that S\bSI\bIG\bGH\bHU\bUP\bP is not sent to the job if  the
              shell  receives a S\bSI\bIG\bGH\bHU\bUP\bP.  If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is present, and neither
              the -\b-a\ba nor the -\b-r\br option is supplied, the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb  is  used.
              If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is supplied, the -\b-a\ba option means to remove or mark
              all jobs; the -\b-r\br option without  a  _\bj_\bo_\bb_\bs_\bp_\be_\bc  argument  restricts
              operation  to running jobs.  The return value is 0 unless a _\bj_\bo_\bb_\b-
              _\bs_\bp_\be_\bc does not specify a valid job.

       e\bec\bch\bho\bo [-\b-n\bne\beE\bE] [_\ba_\br_\bg ...]
              Output the _\ba_\br_\bgs, separated by spaces,  followed  by  a  newline.
              The return status is always 0.  If -\b-n\bn is specified, the trailing
              newline is suppressed.  If the -\b-e\be option is  given,  interpreta-
              tion  of  the following backslash-escaped characters is enabled.
              The -\b-E\bE option disables the interpretation of these escape  char-
              acters,  even  on systems where they are interpreted by default.
              The x\bxp\bpg\bg_\b_e\bec\bch\bho\bo shell option may be used to  dynamically  determine
              whether  or not e\bec\bch\bho\bo expands these escape characters by default.
              e\bec\bch\bho\bo does not interpret -\b--\b- to mean the  end  of  options.   e\bec\bch\bho\bo
              interprets the following escape sequences:
              \\b\a\ba     alert (bell)
              \\b\b\bb     backspace
              \\b\c\bc     suppress further output
              \\b\e\be
              \\b\E\bE     an escape character
              \\b\f\bf     form feed
              \\b\n\bn     new line
              \\b\r\br     carriage return
              \\b\t\bt     horizontal tab
              \\b\v\bv     vertical tab
              \\b\\\b\     backslash
              \\b\0\b0_\bn_\bn_\bn  the  eight-bit  character  whose value is the octal value
                     _\bn_\bn_\bn (zero to three octal digits)
              \\b\x\bx_\bH_\bH   the eight-bit character whose value  is  the  hexadecimal
                     value _\bH_\bH (one or two hex digits)
              \\b\u\bu_\bH_\bH_\bH_\bH the  Unicode (ISO/IEC 10646) character whose value is the
                     hexadecimal value _\bH_\bH_\bH_\bH (one to four hex digits)
              \\b\U\bU_\bH_\bH_\bH_\bH_\bH_\bH_\bH_\bH
                     the Unicode (ISO/IEC 10646) character whose value is  the
                     hexadecimal value _\bH_\bH_\bH_\bH_\bH_\bH_\bH_\bH (one to eight hex digits)

       e\ben\bna\bab\bbl\ble\be [-\b-a\ba] [-\b-d\bdn\bnp\bps\bs] [-\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be] [_\bn_\ba_\bm_\be ...]
              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  -\b-n\bn  is  used,  each  _\bn_\ba_\bm_\be  is disabled; otherwise, _\bn_\ba_\bm_\be_\bs are
              enabled.  For example, to use the t\bte\bes\bst\bt binary found via the P\bPA\bAT\bTH\bH
              instead  of  the  shell builtin version, run ``enable -n test''.
              The -\b-f\bf option means to load the new builtin  command  _\bn_\ba_\bm_\be  from
              shared object _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, on systems that support dynamic loading.
              The -\b-d\bd option will delete a builtin previously loaded  with  -\b-f\bf.
              If no _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp 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 -\b-n\bn
              is supplied, only disabled builtins are printed.  If -\b-a\ba is  sup-
              plied,  the  list printed includes all builtins, with an indica-
              tion of whether or not each is enabled.  If -\b-s\bs is supplied,  the
              output  is restricted to the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl builtins.  The return
              value is 0 unless a _\bn_\ba_\bm_\be is not a shell builtin or there  is  an
              error loading a new builtin from a shared object.

       e\bev\bva\bal\bl [_\ba_\br_\bg ...]
              The  _\ba_\br_\bgs  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 e\bev\bva\bal\bl.  If there are
              no _\ba_\br_\bg_\bs, or only null arguments, e\bev\bva\bal\bl returns 0.

       e\bex\bxe\bec\bc [-\b-c\bcl\bl] [-\b-a\ba _\bn_\ba_\bm_\be] [_\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]]
              If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is specified, it replaces the shell.  No new  process
              is  created.  The _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs become the arguments to _\bc_\bo_\bm_\bm_\ba_\bn_\bd.  If
              the -\b-l\bl option is supplied, the shell places a dash at the begin-
              ning  of  the  zeroth  argument passed to _\bc_\bo_\bm_\bm_\ba_\bn_\bd.  This is what
              _\bl_\bo_\bg_\bi_\bn(1) does.  The -\b-c\bc option causes _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed with
              an  empty environment.  If -\b-a\ba is supplied, the shell passes _\bn_\ba_\bm_\be
              as the zeroth argument to the executed command.  If _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
              not  be executed for some reason, a non-interactive shell exits,
              unless the shell option e\bex\bxe\bec\bcf\bfa\bai\bil\bl is enabled, in  which  case  it
              returns  failure.   An  interactive shell returns failure if the
              file cannot be executed.  If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is not specified, any redi-
              rections take effect in the current shell, and the return status
              is 0.  If there is a redirection error, the return status is  1.

       e\bex\bxi\bit\bt [_\bn]
              Cause  the  shell  to exit with a status of _\bn.  If _\bn is omitted,
              the exit status is that of the last command executed.  A trap on
              E\bEX\bXI\bIT\bT is executed before the shell terminates.

       e\bex\bxp\bpo\bor\brt\bt [-\b-f\bfn\bn] [_\bn_\ba_\bm_\be[=_\bw_\bo_\br_\bd]] ...
       e\bex\bxp\bpo\bor\brt\bt -\b-p\bp
              The  supplied _\bn_\ba_\bm_\be_\bs are marked for automatic export to the envi-
              ronment of subsequently executed commands.  If the -\b-f\bf option  is
              given,  the _\bn_\ba_\bm_\be_\bs refer to functions.  If no _\bn_\ba_\bm_\be_\bs are given, or
              if the -\b-p\bp option is supplied, a  list  of  all  names  that  are
              exported  in  this  shell  is printed.  The -\b-n\bn option causes the
              export property to be removed from each  _\bn_\ba_\bm_\be.   If  a  variable
              name  is  followed by =_\bw_\bo_\br_\bd, the value of the variable is set to
              _\bw_\bo_\br_\bd.  e\bex\bxp\bpo\bor\brt\bt returns an exit status  of  0  unless  an  invalid
              option  is  encountered,  one  of the _\bn_\ba_\bm_\be_\bs is not a valid shell
              variable name, or -\b-f\bf is supplied with a _\bn_\ba_\bm_\be that is not a func-
              tion.

       f\bfc\bc [-\b-e\be _\be_\bn_\ba_\bm_\be] [-\b-l\bln\bnr\br] [_\bf_\bi_\br_\bs_\bt] [_\bl_\ba_\bs_\bt]
       f\bfc\bc -\b-s\bs [_\bp_\ba_\bt=_\br_\be_\bp] [_\bc_\bm_\bd]
              Fix  Command.  In the first form, a range of commands from _\bf_\bi_\br_\bs_\bt
              to _\bl_\ba_\bs_\bt is selected from the history list.  _\bF_\bi_\br_\bs_\bt and  _\bl_\ba_\bs_\bt  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 _\bl_\ba_\bs_\bt is not specified it is set to the
              current  command  for  listing (so that ``fc -l -10'' prints the
              last 10 commands) and to _\bf_\bi_\br_\bs_\bt otherwise.  If _\bf_\bi_\br_\bs_\bt is not spec-
              ified  it is set to the previous command for editing and -16 for
              listing.

              The -\b-n\bn option suppresses the command numbers when listing.   The
              -\b-r\br  option reverses the order of the commands.  If the -\b-l\bl option
              is given, the commands are listed on  standard  output.   Other-
              wise,  the editor given by _\be_\bn_\ba_\bm_\be is invoked on a file containing
              those commands.  If _\be_\bn_\ba_\bm_\be is not given, the value of the  F\bFC\bCE\bED\bDI\bIT\bT
              variable  is used, and the value of E\bED\bDI\bIT\bTO\bOR\bR if F\bFC\bCE\bED\bDI\bIT\bT 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, _\bc_\bo_\bm_\bm_\ba_\bn_\bd is re-executed after each instance
              of _\bp_\ba_\bt is replaced by _\br_\be_\bp.  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 _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt  specify  history
              lines  out  of  range.  If the -\b-e\be 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  _\bc_\bm_\bd  does  not  specify a valid history line, in
              which case f\bfc\bc returns failure.

       f\bfg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc]
              Resume _\bj_\bo_\bb_\bs_\bp_\be_\bc in the foreground, and make it the  current  job.
              If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's notion of the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb
              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 _\bj_\bo_\bb_\bs_\bp_\be_\bc does not spec-
              ify  a  valid  job  or  _\bj_\bo_\bb_\bs_\bp_\be_\bc specifies a job that was started
              without job control.

       g\bge\bet\bto\bop\bpt\bts\bs _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg _\bn_\ba_\bm_\be [_\ba_\br_\bg_\bs]
              g\bge\bet\bto\bop\bpt\bts\bs is used by shell procedures to parse positional  parame-
              ters.   _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg  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, g\bge\bet\bto\bop\bpt\bts\bs
              places the next option in the shell variable _\bn_\ba_\bm_\be,  initializing
              _\bn_\ba_\bm_\be if it does not exist, and the index of the next argument to
              be processed into the variable O\bOP\bPT\bTI\bIN\bND\bD.  O\bOP\bPT\bTI\bIN\bND\bD is initialized to
              1  each  time  the  shell or a shell script is invoked.  When an
              option requires an argument, g\bge\bet\bto\bop\bpt\bts\bs places that  argument  into
              the  variable O\bOP\bPT\bTA\bAR\bRG\bG.  The shell does not reset O\bOP\bPT\bTI\bIN\bND\bD automati-
              cally; it must be  manually  reset  between  multiple  calls  to
              g\bge\bet\bto\bop\bpt\bts\bs within the same shell invocation if a new set of parame-
              ters is to be used.

              When the end of options is encountered,  g\bge\bet\bto\bop\bpt\bts\bs  exits  with  a
              return  value  greater than zero.  O\bOP\bPT\bTI\bIN\bND\bD is set to the index of
              the first non-option argument, and _\bn_\ba_\bm_\be is set to ?.

              g\bge\bet\bto\bop\bpt\bts\bs normally parses the positional parameters, but  if  more
              arguments are given in _\ba_\br_\bg_\bs, g\bge\bet\bto\bop\bpt\bts\bs parses those instead.

              g\bge\bet\bto\bop\bpt\bts\bs  can  report errors in two ways.  If the first character
              of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is a colon, _\bs_\bi_\bl_\be_\bn_\bt error  reporting  is  used.   In
              normal  operation  diagnostic  messages are printed when invalid
              options or missing option arguments  are  encountered.   If  the
              variable  O\bOP\bPT\bTE\bER\bRR\bR  is  set  to  0, no error messages will be dis-
              played, even if the first character of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is not a colon.

              If an invalid option is seen, g\bge\bet\bto\bop\bpt\bts\bs places ? into _\bn_\ba_\bm_\be and, if
              not silent, prints an  error  message  and  unsets  O\bOP\bPT\bTA\bAR\bRG\bG.   If
              g\bge\bet\bto\bop\bpt\bts\bs  is  silent,  the  option  character  found is placed in
              O\bOP\bPT\bTA\bAR\bRG\bG and no diagnostic message is printed.

              If a required argument is not found, and g\bge\bet\bto\bop\bpt\bts\bs is not  silent,
              a  question  mark  (?\b?) is placed in _\bn_\ba_\bm_\be, O\bOP\bPT\bTA\bAR\bRG\bG is unset, and a
              diagnostic message is printed.  If g\bge\bet\bto\bop\bpt\bts\bs  is  silent,  then  a
              colon  (:\b:)  is  placed  in  _\bn_\ba_\bm_\be and O\bOP\bPT\bTA\bAR\bRG\bG is set to the option
              character found.

              g\bge\bet\bto\bop\bpt\bts\bs returns true if an option, specified or unspecified,  is
              found.  It returns false if the end of options is encountered or
              an error occurs.

       h\bha\bas\bsh\bh [-\b-l\blr\br] [-\b-p\bp _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be] [-\b-d\bdt\bt] [_\bn_\ba_\bm_\be]
              Each time h\bha\bas\bsh\bh is invoked, the full pathname of the command _\bn_\ba_\bm_\be
              is  determined  by searching the directories in $\b$P\bPA\bAT\bTH\bH and remem-
              bered.  Any previously-remembered pathname is discarded.  If the
              -\b-p\bp option is supplied, no path search is performed, and _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
              is used as the full file name of the  command.   The  -\b-r\br  option
              causes  the  shell  to  forget all remembered locations.  The -\b-d\bd
              option causes the shell to forget  the  remembered  location  of
              each  _\bn_\ba_\bm_\be.   If the -\b-t\bt option is supplied, the full pathname to
              which each _\bn_\ba_\bm_\be corresponds is printed.  If multiple _\bn_\ba_\bm_\be  argu-
              ments  are  supplied  with  -\b-t\bt,  the  _\bn_\ba_\bm_\be is printed before the
              hashed full pathname.  The -\b-l\bl option causes output  to  be  dis-
              played in a format that may be reused as input.  If no arguments
              are given, or if only -\b-l\bl is supplied, information  about  remem-
              bered  commands  is printed.  The return status is true unless a
              _\bn_\ba_\bm_\be is not found or an invalid option is supplied.

       h\bhe\bel\blp\bp [-\b-d\bdm\bms\bs] [_\bp_\ba_\bt_\bt_\be_\br_\bn]
              Display helpful information about builtin commands.  If  _\bp_\ba_\bt_\bt_\be_\br_\bn
              is  specified, h\bhe\bel\blp\bp gives detailed help on all commands matching
              _\bp_\ba_\bt_\bt_\be_\br_\bn; otherwise help for all the builtins and  shell  control
              structures is printed.
              -\b-d\bd     Display a short description of each _\bp_\ba_\bt_\bt_\be_\br_\bn
              -\b-m\bm     Display the description of each _\bp_\ba_\bt_\bt_\be_\br_\bn in a manpage-like
                     format
              -\b-s\bs     Display only a short usage synopsis for each _\bp_\ba_\bt_\bt_\be_\br_\bn
       The return status is 0 unless no command matches _\bp_\ba_\bt_\bt_\be_\br_\bn.

       h\bhi\bis\bst\bto\bor\bry\by [\b[_\bn]\b]
       h\bhi\bis\bst\bto\bor\bry\by -\b-c\bc
       h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
       h\bhi\bis\bst\bto\bor\bry\by -\b-a\ban\bnr\brw\bw [_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be]
       h\bhi\bis\bst\bto\bor\bry\by -\b-p\bp _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
       h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
              With no options, display the command history list with line num-
              bers.  Lines listed with a *\b* have been modified.  An argument of
              _\bn lists only the last _\bn lines.  If the shell variable  H\bHI\bIS\bST\bTT\bTI\bIM\bME\bE-\b-
              F\bFO\bOR\bRM\bMA\bAT\bT  is  set  and not null, it is used as a format string for
              _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(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  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  is
              supplied,  it  is  used as the name of the history file; if not,
              the value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is used.  Options, if supplied,  have  the
              following meanings:
              -\b-c\bc     Clear the history list by deleting all the entries.
              -\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
                     Delete the history entry at position _\bo_\bf_\bf_\bs_\be_\bt.
              -\b-a\ba     Append  the  ``new'' history lines (history lines entered
                     since the beginning of the current b\bba\bas\bsh\bh session)  to  the
                     history file.
              -\b-n\bn     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 b\bba\bas\bsh\bh session.
              -\b-r\br     Read the contents of the history file and use them as the
                     current history.
              -\b-w\bw     Write  the current history to the history file, overwrit-
                     ing the history file's contents.
              -\b-p\bp     Perform history substitution on the  following  _\ba_\br_\bg_\bs  and
                     display  the  result  on  the  standard output.  Does not
                     store the results in the history list.  Each _\ba_\br_\bg must  be
                     quoted to disable normal history expansion.
              -\b-s\bs     Store  the  _\ba_\br_\bg_\bs  in  the history list as a single entry.
                     The last command in the history list  is  removed  before
                     the _\ba_\br_\bg_\bs are added.

              If  the  H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable is set, the time stamp informa-
              tion associated with each history entry is written to  the  his-
              tory  file, marked with the history comment character.  When the
              history file is read, lines beginning with the  history  comment
              character  followed  immediately  by  a digit are interpreted as
              timestamps for the previous history line.  The return value is 0
              unless  an  invalid option is encountered, an error occurs while
              reading or writing the history file, an invalid _\bo_\bf_\bf_\bs_\be_\bt  is  sup-
              plied as an argument to -\b-d\bd, or the history expansion supplied as
              an argument to -\b-p\bp fails.

       j\bjo\bob\bbs\bs [-\b-l\bln\bnp\bpr\brs\bs] [ _\bj_\bo_\bb_\bs_\bp_\be_\bc ... ]
       j\bjo\bob\bbs\bs -\b-x\bx _\bc_\bo_\bm_\bm_\ba_\bn_\bd [ _\ba_\br_\bg_\bs ... ]
              The first form lists the active jobs.  The options have the fol-
              lowing meanings:
              -\b-l\bl     List process IDs in addition to the normal information.
              -\b-n\bn     Display  information  only  about  jobs that have changed
                     status since the user was last notified of their  status.
              -\b-p\bp     List  only  the  process  ID  of  the job's process group
                     leader.
              -\b-r\br     Restrict output to running jobs.
              -\b-s\bs     Restrict output to stopped jobs.

              If _\bj_\bo_\bb_\bs_\bp_\be_\bc is given, output is restricted to  information  about
              that  job.   The  return status is 0 unless an invalid option is
              encountered or an invalid _\bj_\bo_\bb_\bs_\bp_\be_\bc is supplied.

              If the -\b-x\bx option is supplied, j\bjo\bob\bbs\bs replaces any _\bj_\bo_\bb_\bs_\bp_\be_\bc found in
              _\bc_\bo_\bm_\bm_\ba_\bn_\bd  or  _\ba_\br_\bg_\bs  with  the corresponding process group ID, and
              executes _\bc_\bo_\bm_\bm_\ba_\bn_\bd passing it _\ba_\br_\bg_\bs, returning its exit status.

       k\bki\bil\bll\bl [-\b-s\bs _\bs_\bi_\bg_\bs_\bp_\be_\bc | -\b-n\bn _\bs_\bi_\bg_\bn_\bu_\bm | -\b-_\bs_\bi_\bg_\bs_\bp_\be_\bc] [_\bp_\bi_\bd | _\bj_\bo_\bb_\bs_\bp_\be_\bc] ...
       k\bki\bil\bll\bl -\b-l\bl [_\bs_\bi_\bg_\bs_\bp_\be_\bc | _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs]
              Send the signal named by _\bs_\bi_\bg_\bs_\bp_\be_\bc  or  _\bs_\bi_\bg_\bn_\bu_\bm  to  the  processes
              named  by  _\bp_\bi_\bd or _\bj_\bo_\bb_\bs_\bp_\be_\bc.  _\bs_\bi_\bg_\bs_\bp_\be_\bc is either a case-insensitive
              signal name such as S\bSI\bIG\bGK\bKI\bIL\bLL\bL (with or without the S\bSI\bIG\bG prefix)  or
              a  signal  number; _\bs_\bi_\bg_\bn_\bu_\bm is a signal number.  If _\bs_\bi_\bg_\bs_\bp_\be_\bc is not
              present, then S\bSI\bIG\bGT\bTE\bER\bRM\bM is assumed.  An argument of -\b-l\bl  lists  the
              signal  names.   If any arguments are supplied when -\b-l\bl is given,
              the names of the signals  corresponding  to  the  arguments  are
              listed, and the return status is 0.  The _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs argument to
              -\b-l\bl is a number specifying either a signal  number  or  the  exit
              status  of  a process terminated by a signal.  k\bki\bil\bll\bl returns true
              if at least one signal was successfully sent,  or  false  if  an
              error occurs or an invalid option is encountered.

       l\ble\bet\bt _\ba_\br_\bg [_\ba_\br_\bg ...]
              Each _\ba_\br_\bg is an arithmetic expression to be evaluated (see A\bAR\bRI\bIT\bTH\bH-\b-
              M\bME\bET\bTI\bIC\bC E\bEV\bVA\bAL\bLU\bUA\bAT\bTI\bIO\bON\bN above).  If the last _\ba_\br_\bg evaluates  to  0,  l\ble\bet\bt
              returns 1; 0 is returned otherwise.

       l\blo\boc\bca\bal\bl [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
              For  each  argument, a local variable named _\bn_\ba_\bm_\be is created, and
              assigned _\bv_\ba_\bl_\bu_\be.  The _\bo_\bp_\bt_\bi_\bo_\bn can be any of the  options  accepted
              by d\bde\bec\bcl\bla\bar\bre\be.  When l\blo\boc\bca\bal\bl is used within a function, it causes the
              variable _\bn_\ba_\bm_\be to have a visible scope restricted to  that  func-
              tion and its children.  With no operands, l\blo\boc\bca\bal\bl writes a list of
              local variables to the standard output.  It is an error  to  use
              l\blo\boc\bca\bal\bl when not within a function.  The return status is 0 unless
              l\blo\boc\bca\bal\bl is used outside a function, an invalid _\bn_\ba_\bm_\be  is  supplied,
              or _\bn_\ba_\bm_\be is a readonly variable.

       l\blo\bog\bgo\bou\but\bt Exit a login shell.

       m\bma\bap\bpf\bfi\bil\ble\be  [-\b-n\bn  _\bc_\bo_\bu_\bn_\bt]  [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk]
       [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
       r\bre\bea\bad\bda\bar\brr\bra\bay\by  [-\b-n\bn _\bc_\bo_\bu_\bn_\bt] [-\b-O\bO _\bo_\br_\bi_\bg_\bi_\bn] [-\b-s\bs _\bc_\bo_\bu_\bn_\bt] [-\b-t\bt] [-\b-u\bu _\bf_\bd] [-\b-C\bC _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk]
       [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
              Read  lines from the standard input into the indexed array vari-
              able _\ba_\br_\br_\ba_\by, or from file descriptor _\bf_\bd if the -\b-u\bu option is  sup-
              plied.   The variable M\bMA\bAP\bPF\bFI\bIL\bLE\bE is the default _\ba_\br_\br_\ba_\by.  Options, if
              supplied, have the following meanings:
              -\b-n\bn     Copy at most _\bc_\bo_\bu_\bn_\bt lines.  If _\bc_\bo_\bu_\bn_\bt is 0, all  lines  are
                     copied.
              -\b-O\bO     Begin  assigning  to  _\ba_\br_\br_\ba_\by at index _\bo_\br_\bi_\bg_\bi_\bn.  The default
                     index is 0.
              -\b-s\bs     Discard the first _\bc_\bo_\bu_\bn_\bt lines read.
              -\b-t\bt     Remove a trailing newline from each line read.
              -\b-u\bu     Read lines from file descriptor _\bf_\bd instead of  the  stan-
                     dard input.
              -\b-C\bC     Evaluate  _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk each time _\bq_\bu_\ba_\bn_\bt_\bu_\bm lines are read.  The
                     -\b-c\bc option specifies _\bq_\bu_\ba_\bn_\bt_\bu_\bm.
              -\b-c\bc     Specify the number of lines read  between  each  call  to
                     _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk.

              If  -\b-C\bC  is  specified  without  -\b-c\bc, the default quantum is 5000.
              When _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk is evaluated, it is supplied the index of the next
              array element to be assigned and the line to be assigned to that
              element as additional arguments.  _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk  is  evaluated  after
              the line is read but before the array element is assigned.

              If  not  supplied  with  an  explicit origin, m\bma\bap\bpf\bfi\bil\ble\be will clear
              _\ba_\br_\br_\ba_\by before assigning to it.

              m\bma\bap\bpf\bfi\bil\ble\be returns successfully unless an invalid option or  option
              argument  is  supplied,  _\ba_\br_\br_\ba_\by is invalid or unassignable, or if
              _\ba_\br_\br_\ba_\by is not an indexed array.

       p\bpo\bop\bpd\bd [-n\bn] [+_\bn] [-_\bn]
              Removes entries from the directory stack.   With  no  arguments,
              removes  the  top directory from the stack, and performs a c\bcd\bd to
              the new top directory.  Arguments, if supplied, have the follow-
              ing meanings:
              -\b-n\bn     Suppresses  the  normal change of directory when removing
                     directories from the stack, so that  only  the  stack  is
                     manipulated.
              +\b+_\bn     Removes  the _\bnth entry counting from the left of the list
                     shown by d\bdi\bir\brs\bs, starting with zero.  For  example:  ``popd
                     +0'' removes the first directory, ``popd +1'' the second.
              -\b-_\bn     Removes the _\bnth entry counting from the right of the list
                     shown  by  d\bdi\bir\brs\bs, starting with zero.  For example: ``popd
                     -0'' removes the last directory, ``popd -1'' the next  to
                     last.

              If  the p\bpo\bop\bpd\bd command is successful, a d\bdi\bir\brs\bs is performed as well,
              and the return status is 0.  p\bpo\bop\bpd\bd 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.

       p\bpr\bri\bin\bnt\btf\bf [-\b-v\bv _\bv_\ba_\br] _\bf_\bo_\br_\bm_\ba_\bt [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
              Write  the  formatted _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs to the standard output under the
              control of the _\bf_\bo_\br_\bm_\ba_\bt.  The -\b-v\bv option causes the  output  to  be
              assigned  to  the  variable _\bv_\ba_\br rather than being printed to the
              standard output.

              The _\bf_\bo_\br_\bm_\ba_\bt 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  _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt.   In
              addition to the standard _\bp_\br_\bi_\bn_\bt_\bf(1) format specifications, p\bpr\bri\bin\bnt\btf\bf
              interprets the following extensions:
              %\b%b\bb     causes p\bpr\bri\bin\bnt\btf\bf to expand backslash escape sequences in the
                     corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt (except that \\b\c\bc terminates output,
                     backslashes in \\b\'\b', \\b\"\b", and \\b\?\b? are not removed, and  octal
                     escapes beginning with \\b\0\b0 may contain up to four digits).
              %\b%q\bq     causes p\bpr\bri\bin\bnt\btf\bf to output the corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt  in  a
                     format that can be reused as shell input.
              %\b%(\b(_\bd_\ba_\bt_\be_\bf_\bm_\bt)\b)T\bT
                     causes  p\bpr\bri\bin\bnt\btf\bf  to  output the date-time string resulting
                     from using _\bd_\ba_\bt_\be_\bf_\bm_\bt as a format  string  for  _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
                     The corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt is an integer representing the
                     number of seconds since the epoch.  Two special  argument
                     values  may  be used: -1 represents the current time, and
                     -2 represents the time the shell was invoked.

              Arguments to non-string format specifiers are treated as C  con-
              stants, except that a leading plus or minus sign is allowed, and
              if the leading character is a single or double quote, the  value
              is the ASCII value of the following character.

              The  _\bf_\bo_\br_\bm_\ba_\bt  is  reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
              _\bm_\be_\bn_\bt_\bs.  If the _\bf_\bo_\br_\bm_\ba_\bt requires more _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs 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.

       p\bpu\bus\bsh\bhd\bd [-\b-n\bn] [+_\bn] [-_\bn]
       p\bpu\bus\bsh\bhd\bd [-\b-n\bn] [_\bd_\bi_\br]
              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:
              -\b-n\bn     Suppresses  the  normal  change  of directory when adding
                     directories to the stack,  so  that  only  the  stack  is
                     manipulated.
              +\b+_\bn     Rotates  the  stack  so  that the _\bnth directory (counting
                     from the left of the list shown by  d\bdi\bir\brs\bs,  starting  with
                     zero) is at the top.
              -\b-_\bn     Rotates  the  stack  so  that the _\bnth directory (counting
                     from the right of the list shown by d\bdi\bir\brs\bs,  starting  with
                     zero) is at the top.
              _\bd_\bi_\br    Adds _\bd_\bi_\br to the directory stack at the top, making it the
                     new current working directory.

              If the p\bpu\bus\bsh\bhd\bd command is successful, a d\bdi\bir\brs\bs is performed as well.
              If  the first form is used, p\bpu\bus\bsh\bhd\bd returns 0 unless the cd to _\bd_\bi_\br
              fails.  With the second form, p\bpu\bus\bsh\bhd\bd 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.

       p\bpw\bwd\bd [-\b-L\bLP\bP]
              Print  the  absolute  pathname of the current working directory.
              The pathname printed contains no symbolic links if the -\b-P\bP option
              is supplied or the -\b-o\bo p\bph\bhy\bys\bsi\bic\bca\bal\bl option to the s\bse\bet\bt builtin command
              is enabled.  If the -\b-L\bL 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.

       r\bre\bea\bad\bd [-\b-e\ber\brs\bs] [-\b-a\ba _\ba_\bn_\ba_\bm_\be] [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\b-i\bi _\bt_\be_\bx_\bt] [-\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs] [-\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs] [-\b-p\bp
       _\bp_\br_\bo_\bm_\bp_\bt] [-\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt] [-\b-u\bu _\bf_\bd] [_\bn_\ba_\bm_\be ...]
              One  line  is  read  from  the  standard input, or from the file
              descriptor _\bf_\bd supplied as an argument to the -\b-u\bu option, and  the
              first word is assigned to the first _\bn_\ba_\bm_\be, the second word to the
              second _\bn_\ba_\bm_\be, and so on, with leftover words and their  interven-
              ing  separators  assigned  to the last _\bn_\ba_\bm_\be.  If there are fewer
              words read from the input stream than names, the remaining names
              are  assigned  empty  values.  The characters in I\bIF\bFS\bS are used to
              split the line into words.  The backslash character (\\b\)  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:
              -\b-a\ba _\ba_\bn_\ba_\bm_\be
                     The words are assigned to sequential indices of the array
                     variable _\ba_\bn_\ba_\bm_\be, starting at 0.  _\ba_\bn_\ba_\bm_\be is unset before any
                     new  values  are  assigned.   Other  _\bn_\ba_\bm_\be  arguments  are
                     ignored.
              -\b-d\bd _\bd_\be_\bl_\bi_\bm
                     The first character of _\bd_\be_\bl_\bi_\bm is  used  to  terminate  the
                     input line, rather than newline.
              -\b-e\be     If the standard input is coming from a terminal, r\bre\bea\bad\bdl\bli\bin\bne\be
                     (see R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE above) is used to obtain the  line.   Read-
                     line  uses  the  current (or default, if line editing was
                     not previously active) editing settings.
              -\b-i\bi _\bt_\be_\bx_\bt
                     If r\bre\bea\bad\bdl\bli\bin\bne\be is being used  to  read  the  line,  _\bt_\be_\bx_\bt  is
                     placed into the editing buffer before editing begins.
              -\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs
                     r\bre\bea\bad\bd  returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
                     waiting for a complete line of input, but honor a  delim-
                     iter  if fewer than _\bn_\bc_\bh_\ba_\br_\bs characters are read before the
                     delimiter.
              -\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs
                     r\bre\bea\bad\bd returns  after  reading  exactly  _\bn_\bc_\bh_\ba_\br_\bs  characters
                     rather  than waiting for a complete line of input, unless
                     EOF is encountered or r\bre\bea\bad\bd times out.  Delimiter  charac-
                     ters  encountered  in the input are not treated specially
                     and do not cause r\bre\bea\bad\bd to return until  _\bn_\bc_\bh_\ba_\br_\bs  characters
                     are read.
              -\b-p\bp _\bp_\br_\bo_\bm_\bp_\bt
                     Display _\bp_\br_\bo_\bm_\bp_\bt 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.
              -\b-r\br     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.
              -\b-s\bs     Silent mode.  If input is coming from a terminal, charac-
                     ters are not echoed.
              -\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt
                     Cause  r\bre\bea\bad\bd  to time out and return failure if a complete
                     line of input is not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds.   _\bt_\bi_\bm_\be_\b-
                     _\bo_\bu_\bt  may  be  a  decimal number with a fractional portion
                     following the decimal point.  This option is only  effec-
                     tive  if  r\bre\bea\bad\bd is reading input from a terminal, pipe, or
                     other special file; it has no effect  when  reading  from
                     regular  files.  If _\bt_\bi_\bm_\be_\bo_\bu_\bt is 0, r\bre\bea\bad\bd returns success if
                     input is available  on  the  specified  file  descriptor,
                     failure  otherwise.   The exit status is greater than 128
                     if the timeout is exceeded.
              -\b-u\bu _\bf_\bd  Read input from file descriptor _\bf_\bd.

              If no _\bn_\ba_\bm_\be_\bs are supplied, the line read is assigned to the vari-
              able  R\bRE\bEP\bPL\bLY\bY.   The  return  code  is zero, unless end-of-file is
              encountered, r\bre\bea\bad\bd times out (in which case the  return  code  is
              greater  than 128), or an invalid file descriptor is supplied as
              the argument to -\b-u\bu.

       r\bre\bea\bad\bdo\bon\bnl\bly\by [-\b-a\baA\bAp\bpf\bf] [_\bn_\ba_\bm_\be[=_\bw_\bo_\br_\bd] ...]
              The given _\bn_\ba_\bm_\be_\bs are marked readonly; the values of  these  _\bn_\ba_\bm_\be_\bs
              may  not  be changed by subsequent assignment.  If the -\b-f\bf option
              is supplied, the functions corresponding to  the  _\bn_\ba_\bm_\be_\bs  are  so
              marked.   The  -\b-a\ba  option  restricts  the  variables  to indexed
              arrays; the -\b-A\bA option restricts  the  variables  to  associative
              arrays.   If no _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is
              supplied, a list of all  readonly  names  is  printed.   The  -\b-p\bp
              option  causes  output  to  be displayed in a format that may be
              reused as input.  If a variable name is followed by  =_\bw_\bo_\br_\bd,  the
              value  of  the  variable is set to _\bw_\bo_\br_\bd.  The return status is 0
              unless an invalid option is encountered, one of the _\bn_\ba_\bm_\be_\bs is not
              a  valid shell variable name, or -\b-f\bf is supplied with a _\bn_\ba_\bm_\be that
              is not a function.

       r\bre\bet\btu\bur\brn\bn [_\bn]
              Causes a function to exit with the return value specified by  _\bn.
              If  _\bn  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 .\b.  (s\bso\bou\bur\brc\bce\be) command, it
              causes the shell to stop executing that script and return either
              _\bn  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 .\b., the return
              status is false.  Any command associated with the R\bRE\bET\bTU\bUR\bRN\bN trap is
              executed  before execution resumes after the function or script.

       s\bse\bet\bt [-\b--\b-a\bab\bbe\bef\bfh\bhk\bkm\bmn\bnp\bpt\btu\buv\bvx\bxB\bBC\bCE\bEH\bHP\bPT\bT] [-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be] [_\ba_\br_\bg ...]
       s\bse\bet\bt [+\b+a\bab\bbe\bef\bfh\bhk\bkm\bmn\bnp\bpt\btu\buv\bvx\bxB\bBC\bCE\bEH\bHP\bPT\bT] [+\b+o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be] [_\ba_\br_\bg ...]
              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 _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, 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 option processing are treated as  val-
              ues for the positional parameters and are assigned, in order, to
              $\b$1\b1, $\b$2\b2, .\b..\b..\b.  $\b$_\bn.  Options,  if  specified,  have  the  following
              meanings:
              -\b-a\ba      Automatically  mark  variables  and  functions which are
                      modified or created for export  to  the  environment  of
                      subsequent commands.
              -\b-b\bb      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.
              -\b-e\be      Exit  immediately  if a _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be (which may consist of a
                      single _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd),  a _\bs_\bu_\bb_\bs_\bh_\be_\bl_\bl command enclosed  in
                      parentheses,  or one of the commands executed as part of
                      a command list enclosed by  braces  (see  S\bSH\bHE\bEL\bLL\bL  G\bGR\bRA\bAM\bMM\bMA\bAR\bR
                      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  w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword,
                      part of the test  following  the  i\bif\bf  or  e\bel\bli\bif\bf  reserved
                      words,  part  of any command executed in a &\b&&\b& or |\b||\b| list
                      except the command following the final  &\b&&\b&  or  |\b||\b|,  any
                      command  in a pipeline but the last, or if the command's
                      return value is being inverted with !\b!.  A trap  on  E\bER\bRR\bR,
                      if set, is executed before the shell exits.  This option
                      applies to the shell environment and each subshell envi-
                      ronment  separately  (see  C\bCO\bOM\bMM\bMA\bAN\bND\bD E\bEX\bXE\bEC\bCU\bUT\bTI\bIO\bON\bN E\bEN\bNV\bVI\bIR\bRO\bON\bNM\bME\bEN\bNT\bT
                      above), and may cause subshells to exit before executing
                      all the commands in the subshell.
              -\b-f\bf      Disable pathname expansion.
              -\b-h\bh      Remember  the location of commands as they are looked up
                      for execution.  This is enabled by default.
              -\b-k\bk      All arguments in the form of assignment  statements  are
                      placed  in the environment for a command, not just those
                      that precede the command name.
              -\b-m\bm      Monitor mode.  Job control is enabled.  This  option  is
                      on  by  default  for  interactive shells on systems that
                      support it (see J\bJO\bOB\bB  C\bCO\bON\bNT\bTR\bRO\bOL\bL  above).   Background  pro-
                      cesses  run  in a separate process group and a line con-
                      taining their exit status is printed upon their  comple-
                      tion.
              -\b-n\bn      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.
              -\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
                      The _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be can be one of the following:
                      a\bal\bll\ble\bex\bxp\bpo\bor\brt\bt
                              Same as -\b-a\ba.
                      b\bbr\bra\bac\bce\bee\bex\bxp\bpa\ban\bnd\bd
                              Same as -\b-B\bB.
                      e\bem\bma\bac\bcs\bs   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 -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg option.  This also  affects  the
                              editing interface used for r\bre\bea\bad\bd -\b-e\be.
                      e\ber\brr\bre\bex\bxi\bit\bt Same as -\b-e\be.
                      e\ber\brr\brt\btr\bra\bac\bce\be
                              Same as -\b-E\bE.
                      f\bfu\bun\bnc\bct\btr\bra\bac\bce\be
                              Same as -\b-T\bT.
                      h\bha\bas\bsh\bha\bal\bll\bl Same as -\b-h\bh.
                      h\bhi\bis\bst\bte\bex\bxp\bpa\ban\bnd\bd
                              Same as -\b-H\bH.
                      h\bhi\bis\bst\bto\bor\bry\by Enable command history, as described above under
                              H\bHI\bIS\bST\bTO\bOR\bRY\bY.  This option is on by default in inter-
                              active shells.
                      i\big\bgn\bno\bor\bre\bee\beo\bof\bf
                              The   effect   is   as   if  the  shell  command
                              ``IGNOREEOF=10'' had been  executed  (see  S\bSh\bhe\bel\bll\bl
                              V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs above).
                      k\bke\bey\byw\bwo\bor\brd\bd Same as -\b-k\bk.
                      m\bmo\bon\bni\bit\bto\bor\br Same as -\b-m\bm.
                      n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br
                              Same as -\b-C\bC.
                      n\bno\boe\bex\bxe\bec\bc  Same as -\b-n\bn.
                      n\bno\bog\bgl\blo\bob\bb  Same as -\b-f\bf.
                      n\bno\bol\blo\bog\bg   Currently ignored.
                      n\bno\bot\bti\bif\bfy\by  Same as -\b-b\bb.
                      n\bno\bou\bun\bns\bse\bet\bt Same as -\b-u\bu.
                      o\bon\bne\bec\bcm\bmd\bd  Same as -\b-t\bt.
                      p\bph\bhy\bys\bsi\bic\bca\bal\bl
                              Same as -\b-P\bP.
                      p\bpi\bip\bpe\bef\bfa\bai\bil\bl
                              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.
                      p\bpo\bos\bsi\bix\bx   Change  the  behavior  of b\bba\bas\bsh\bh where the default
                              operation differs from  the  POSIX  standard  to
                              match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be).
                      p\bpr\bri\biv\bvi\bil\ble\beg\bge\bed\bd
                              Same as -\b-p\bp.
                      v\bve\ber\brb\bbo\bos\bse\be Same as -\b-v\bv.
                      v\bvi\bi      Use  a  vi-style command line editing interface.
                              This also affects the editing interface used for
                              r\bre\bea\bad\bd -\b-e\be.
                      x\bxt\btr\bra\bac\bce\be  Same as -\b-x\bx.
                      If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, the values of the
                      current options are printed.  If +\b+o\bo is supplied with  no
                      _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be,  a  series  of s\bse\bet\bt commands to recreate the
                      current option settings is  displayed  on  the  standard
                      output.
              -\b-p\bp      Turn  on  _\bp_\br_\bi_\bv_\bi_\bl_\be_\bg_\be_\bd  mode.   In this mode, the $\b$E\bEN\bNV\bV and
                      $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV files are not processed, shell  functions  are
                      not  inherited  from the environment, and the S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
                      B\bBA\bAS\bSH\bHO\bOP\bPT\bTS\bS, C\bCD\bDP\bPA\bAT\bTH\bH,  and  G\bGL\bLO\bOB\bBI\bIG\bGN\bNO\bOR\bRE\bE  variables,  if  they
                      appear in the environment, are ignored.  If the shell is
                      started with the effective user (group) id not equal  to
                      the  real user (group) id, and the -\b-p\bp option is not sup-
                      plied, these actions are taken and the effective user id
                      is  set  to  the real user id.  If the -\b-p\bp option is sup-
                      plied 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.
              -\b-t\bt      Exit after reading and executing one command.
              -\b-u\bu      Treat unset variables and parameters other than the spe-
                      cial  parameters "@" and "*" as an error when performing
                      parameter expansion.  If expansion is  attempted  on  an
                      unset  variable  or parameter, the shell prints an error
                      message, and, if not interactive, exits with a  non-zero
                      status.
              -\b-v\bv      Print shell input lines as they are read.
              -\b-x\bx      After  expanding  each _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, f\bfo\bor\br command, c\bca\bas\bse\be
                      command, s\bse\bel\ble\bec\bct\bt command, or arithmetic f\bfo\bor\br command, dis-
                      play  the expanded value of P\bPS\bS4\b4, followed by the command
                      and its expanded arguments or associated word list.
              -\b-B\bB      The shell performs brace expansion (see B\bBr\bra\bac\bce\be  E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn
                      above).  This is on by default.
              -\b-C\bC      If  set,  b\bba\bas\bsh\bh  does not overwrite an existing file with
                      the >\b>, >\b>&\b&, and <\b<>\b> redirection operators.   This  may  be
                      overridden when creating output files by using the redi-
                      rection operator >\b>|\b| instead of >\b>.
              -\b-E\bE      If set, any trap on E\bER\bRR\bR is inherited by shell functions,
                      command  substitutions,  and commands executed in a sub-
                      shell environment.  The E\bER\bRR\bR trap is normally not  inher-
                      ited in such cases.
              -\b-H\bH      Enable !\b!  style history substitution.  This option is on
                      by default when the shell is interactive.
              -\b-P\bP      If set, the shell does not follow  symbolic  links  when
                      executing  commands  such  as c\bcd\bd that change the current
                      working  directory.   It  uses  the  physical  directory
                      structure instead.  By default, b\bba\bas\bsh\bh follows the logical
                      chain of  directories  when  performing  commands  which
                      change the current directory.
              -\b-T\bT      If  set,  any traps on D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN are inherited by
                      shell functions,  command  substitutions,  and  commands
                      executed  in  a  subshell  environment.   The  D\bDE\bEB\bBU\bUG\bG and
                      R\bRE\bET\bTU\bUR\bRN\bN traps are normally not inherited in such cases.
              -\b--\b-      If no arguments follow this option, then the  positional
                      parameters are unset.  Otherwise, the positional parame-
                      ters are set to the _\ba_\br_\bgs, even if  some  of  them  begin
                      with a -\b-.
              -\b-       Signal  the  end of options, cause all remaining _\ba_\br_\bgs to
                      be assigned to the positional parameters.  The -\b-x\bx and -\b-v\bv
                      options are turned off.  If there are no _\ba_\br_\bgs, 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 $\b$-\b-.  The
              return status is always true unless an invalid option is encoun-
              tered.

       s\bsh\bhi\bif\bft\bt [_\bn]
              The  positional  parameters  from _\bn+1 ... are renamed to $\b$1\b1 .\b..\b..\b..\b.
              Parameters represented by the numbers  $\b$#\b#  down  to  $\b$#\b#-_\bn+1  are
              unset.   _\bn  must  be a non-negative number less than or equal to
              $\b$#\b#.  If _\bn is 0, no parameters are changed.  If _\bn is  not  given,
              it  is assumed to be 1.  If _\bn is greater than $\b$#\b#, the positional
              parameters are not changed.  The return status is  greater  than
              zero if _\bn is greater than $\b$#\b# or less than zero; otherwise 0.

       s\bsh\bho\bop\bpt\bt [-\b-p\bpq\bqs\bsu\bu] [-\b-o\bo] [_\bo_\bp_\bt_\bn_\ba_\bm_\be ...]
              Toggle the values of variables controlling optional shell behav-
              ior.  With no options, or with the -\b-p\bp option, a list of all set-
              table options is displayed, with an indication of whether or not
              each is set.  The -\b-p\bp option causes output to be displayed  in  a
              form  that  may be reused as input.  Other options have the fol-
              lowing meanings:
              -\b-s\bs     Enable (set) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
              -\b-u\bu     Disable (unset) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
              -\b-q\bq     Suppresses normal output (quiet mode); the return  status
                     indicates whether the _\bo_\bp_\bt_\bn_\ba_\bm_\be is set or unset.  If multi-
                     ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return  sta-
                     tus  is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
                     wise.
              -\b-o\bo     Restricts the values of _\bo_\bp_\bt_\bn_\ba_\bm_\be to be those  defined  for
                     the -\b-o\bo option to the s\bse\bet\bt builtin.

              If  either  -\b-s\bs or -\b-u\bu is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, the dis-
              play is limited to those options which are set or unset, respec-
              tively.   Unless otherwise noted, the s\bsh\bho\bop\bpt\bt options are disabled
              (unset) by default.

              The return status when listing options is zero if  all  _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs
              are  enabled,  non-zero  otherwise.   When  setting or unsetting
              options, the return status is zero unless an _\bo_\bp_\bt_\bn_\ba_\bm_\be  is  not  a
              valid shell option.

              The list of s\bsh\bho\bop\bpt\bt options is:

              a\bau\but\bto\boc\bcd\bd  If  set,  a command name that is the name of a directory
                      is executed as if it were the argument to  the  c\bcd\bd  com-
                      mand.  This option is only used by interactive shells.
              c\bcd\bda\bab\bbl\ble\be_\b_v\bva\bar\brs\bs
                      If  set,  an  argument to the c\bcd\bd builtin command that is
                      not a directory is assumed to be the name of a  variable
                      whose value is the directory to change to.
              c\bcd\bds\bsp\bpe\bel\bll\bl If set, minor errors in the spelling of a directory com-
                      ponent in a c\bcd\bd 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.
              c\bch\bhe\bec\bck\bkh\bha\bas\bsh\bh
                      If set, b\bba\bas\bsh\bh 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.
              c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs
                      If set, b\bba\bas\bsh\bh lists the status of any stopped and running
                      jobs  before  exiting an interactive shell.  If any jobs
                      are running, this causes the exit to be deferred until a
                      second  exit is attempted without an intervening command
                      (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL above).   The  shell  always  postpones
                      exiting if any jobs are stopped.
              c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be
                      If  set,  b\bba\bas\bsh\bh checks the window size after each command
                      and, if necessary, updates the values of L\bLI\bIN\bNE\bES\bS and  C\bCO\bOL\bL-\b-
                      U\bUM\bMN\bNS\bS.
              c\bcm\bmd\bdh\bhi\bis\bst\bt If  set,  b\bba\bas\bsh\bh attempts to save all lines of a multiple-
                      line command in the same  history  entry.   This  allows
                      easy re-editing of multi-line commands.
              c\bco\bom\bmp\bpa\bat\bt3\b31\b1
                      If set, b\bba\bas\bsh\bh changes its behavior to that of version 3.1
                      with respect to quoted arguments to the  [\b[[\b[  conditional
                      command's =\b=~\b~ operator.
              c\bco\bom\bmp\bpa\bat\bt3\b32\b2
                      If set, b\bba\bas\bsh\bh changes its behavior to that of version 3.2
                      with respect to locale-specific string  comparison  when
                      using  the  [\b[[\b[  conditional command's <\b< and >\b> operators.
                      Bash versions prior to bash-4.1 use ASCII collation  and
                      _\bs_\bt_\br_\bc_\bm_\bp(3);  bash-4.1  and later use the current locale's
                      collation sequence and _\bs_\bt_\br_\bc_\bo_\bl_\bl(3).
              c\bco\bom\bmp\bpa\bat\bt4\b40\b0
                      If set, b\bba\bas\bsh\bh changes its behavior to that of version 4.0
                      with  respect  to locale-specific string comparison when
                      using the [\b[[\b[ conditional command's  <\b<  and  >\b>  operators
                      (see  previous  item)  and  the effect of interrupting a
                      command list.
              c\bco\bom\bmp\bpa\bat\bt4\b41\b1
                      @item compat41 If set, b\bba\bas\bsh\bh, when in posix mode,  treats
                      a single quote in a double-quoted parameter expansion as
                      a special character.  The single quotes must  match  (an
                      even  number)  and  the  characters  between  the single
                      quotes are considered quoted.  This is the  behavior  of
                      posix mode through version 4.1.  The default bash behav-
                      ior remains as in previous versions.
              d\bdi\bir\brs\bsp\bpe\bel\bll\bl
                      If set, b\bba\bas\bsh\bh attempts spelling correction  on  directory
                      names  during word completion if the directory name ini-
                      tially supplied does not exist.
              d\bdo\bot\btg\bgl\blo\bob\bb If set, b\bba\bas\bsh\bh includes filenames beginning with a `.'  in
                      the results of pathname expansion.
              e\bex\bxe\bec\bcf\bfa\bai\bil\bl
                      If set, a non-interactive shell will not exit if it can-
                      not execute the file specified as  an  argument  to  the
                      e\bex\bxe\bec\bc  builtin  command.   An  interactive shell does not
                      exit if e\bex\bxe\bec\bc fails.
              e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs
                      If set, aliases are expanded as  described  above  under
                      A\bAL\bLI\bIA\bAS\bSE\bES\bS.  This option is enabled by default for interac-
                      tive shells.
              e\bex\bxt\btd\bde\beb\bbu\bug\bg
                      If set,  behavior  intended  for  use  by  debuggers  is
                      enabled:
                      1\b1.\b.     The -\b-F\bF option to the d\bde\bec\bcl\bla\bar\bre\be builtin displays the
                             source file name and line number corresponding to
                             each function name supplied as an argument.
                      2\b2.\b.     If  the  command  run by the D\bDE\bEB\bBU\bUG\bG trap returns a
                             non-zero value, the next command is  skipped  and
                             not executed.
                      3\b3.\b.     If  the  command  run by the D\bDE\bEB\bBU\bUG\bG 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 .\b. or s\bso\bou\bur\brc\bce\be  builtins),  a  call  to
                             r\bre\bet\btu\bur\brn\bn is simulated.
                      4\b4.\b.     B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGC\bC  and B\bBA\bAS\bSH\bH_\b_A\bAR\bRG\bGV\bV are updated as described
                             in their descriptions above.
                      5\b5.\b.     Function tracing is enabled:   command  substitu-
                             tion, shell functions, and subshells invoked with
                             (\b( _\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the D\bDE\bEB\bBU\bUG\bG and R\bRE\bET\bTU\bUR\bRN\bN traps.
                      6\b6.\b.     Error tracing is enabled:  command  substitution,
                             shell  functions,  and  subshells  invoked with (\b(
                             _\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the E\bER\bRR\bR trap.
              e\bex\bxt\btg\bgl\blo\bob\bb If set, the extended pattern matching features described
                      above under P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn are enabled.
              e\bex\bxt\btq\bqu\buo\bot\bte\be
                      If  set,  $\b$'_\bs_\bt_\br_\bi_\bn_\bg'  and  $\b$"_\bs_\bt_\br_\bi_\bn_\bg" quoting is performed
                      within  $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b}  expansions  enclosed   in   double
                      quotes.  This option is enabled by default.
              f\bfa\bai\bil\blg\bgl\blo\bob\bb
                      If  set,  patterns  which fail to match filenames during
                      pathname expansion result in an expansion error.
              f\bfo\bor\brc\bce\be_\b_f\bfi\big\bgn\bno\bor\bre\be
                      If set, the suffixes  specified  by  the  F\bFI\bIG\bGN\bNO\bOR\bRE\bE  shell
                      variable  cause words to be ignored when performing word
                      completion even if the ignored words are the only possi-
                      ble  completions.   See  S\bSH\bHE\bEL\bLL\bL  V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS  above  for  a
                      description of  F\bFI\bIG\bGN\bNO\bOR\bRE\bE.   This  option  is  enabled  by
                      default.
              g\bgl\blo\bob\bbs\bst\bta\bar\br
                      If set, the pattern *\b**\b* used in a pathname expansion con-
                      text will match a files and zero or more directories and
                      subdirectories.  If the pattern is followed by a /\b/, only
                      directories and subdirectories match.
              g\bgn\bnu\bu_\b_e\ber\brr\brf\bfm\bmt\bt
                      If set, shell error messages are written in the standard
                      GNU error message format.
              h\bhi\bis\bst\bta\bap\bpp\bpe\ben\bnd\bd
                      If  set,  the history list is appended to the file named
                      by the value of the H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE  variable  when  the  shell
                      exits, rather than overwriting the file.
              h\bhi\bis\bst\btr\bre\bee\bed\bdi\bit\bt
                      If  set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, a user is given the
                      opportunity to re-edit a failed history substitution.
              h\bhi\bis\bst\btv\bve\ber\bri\bif\bfy\by
                      If set, and r\bre\bea\bad\bdl\bli\bin\bne\be 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 r\bre\bea\bad\bdl\bli\bin\bne\be editing buffer, allowing further modi-
                      fication.
              h\bho\bos\bst\btc\bco\bom\bmp\bpl\ble\bet\bte\be
                      If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will attempt to
                      perform  hostname  completion when a word containing a @\b@
                      is  being  completed  (see  C\bCo\bom\bmp\bpl\ble\bet\bti\bin\bng\bg  under   R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE
                      above).  This is enabled by default.
              h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt
                      If set, b\bba\bas\bsh\bh will send S\bSI\bIG\bGH\bHU\bUP\bP to all jobs when an inter-
                      active login shell exits.
              i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs
                      If set, allow a word beginning with #\b# to cause that word
                      and  all remaining characters on that line to be ignored
                      in an interactive  shell  (see  C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS  above).   This
                      option is enabled by default.
              l\bla\bas\bst\btp\bpi\bip\bpe\be
                      If  set,  and  job control is not active, the shell runs
                      the last command of a pipeline not executed in the back-
                      ground in the current shell environment.
              l\bli\bit\bth\bhi\bis\bst\bt If  set,  and  the c\bcm\bmd\bdh\bhi\bis\bst\bt option is enabled, multi-line
                      commands are saved to the history with embedded newlines
                      rather than using semicolon separators where possible.
              l\blo\bog\bgi\bin\bn_\b_s\bsh\bhe\bel\bll\bl
                      The  shell  sets this option if it is started as a login
                      shell (see I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN above).   The  value  may  not  be
                      changed.
              m\bma\bai\bil\blw\bwa\bar\brn\bn
                      If  set,  and  a file that b\bba\bas\bsh\bh is checking for mail has
                      been accessed since the last time it  was  checked,  the
                      message  ``The  mail in _\bm_\ba_\bi_\bl_\bf_\bi_\bl_\be has been read'' is dis-
                      played.
              n\bno\bo_\b_e\bem\bmp\bpt\bty\by_\b_c\bcm\bmd\bd_\b_c\bco\bom\bmp\bpl\ble\bet\bti\bio\bon\bn
                      If set, and  r\bre\bea\bad\bdl\bli\bin\bne\be  is  being  used,  b\bba\bas\bsh\bh  will  not
                      attempt to search the P\bPA\bAT\bTH\bH for possible completions when
                      completion is attempted on an empty line.
              n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb
                      If set, b\bba\bas\bsh\bh matches  filenames  in  a  case-insensitive
                      fashion when performing pathname expansion (see P\bPa\bat\bth\bhn\bna\bam\bme\be
                      E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn above).
              n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh
                      If set, b\bba\bas\bsh\bh  matches  patterns  in  a  case-insensitive
                      fashion when performing matching while executing c\bca\bas\bse\be or
                      [\b[[\b[ conditional commands.
              n\bnu\bul\bll\blg\bgl\blo\bob\bb
                      If set, b\bba\bas\bsh\bh allows patterns which match no  files  (see
                      P\bPa\bat\bth\bhn\bna\bam\bme\be  E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn  above)  to expand to a null string,
                      rather than themselves.
              p\bpr\bro\bog\bgc\bco\bom\bmp\bp
                      If set, the programmable completion facilities (see P\bPr\bro\bo-\b-
                      g\bgr\bra\bam\bmm\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn above) are enabled.  This option is
                      enabled by default.
              p\bpr\bro\bom\bmp\bpt\btv\bva\bar\brs\bs
                      If set, prompt strings undergo parameter expansion, com-
                      mand   substitution,  arithmetic  expansion,  and  quote
                      removal after being expanded as described  in  P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG
                      above.  This option is enabled by default.
              r\bre\bes\bst\btr\bri\bic\bct\bte\bed\bd_\b_s\bsh\bhe\bel\bll\bl
                      The   shell  sets  this  option  if  it  is  started  in
                      restricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL 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.
              s\bsh\bhi\bif\bft\bt_\b_v\bve\ber\brb\bbo\bos\bse\be
                      If  set,  the s\bsh\bhi\bif\bft\bt builtin prints an error message when
                      the shift count exceeds the number of positional parame-
                      ters.
              s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh
                      If set, the s\bso\bou\bur\brc\bce\be (.\b.) builtin uses the value of P\bPA\bAT\bTH\bH to
                      find the directory containing the file  supplied  as  an
                      argument.  This option is enabled by default.
              x\bxp\bpg\bg_\b_e\bec\bch\bho\bo
                      If   set,  the  e\bec\bch\bho\bo  builtin  expands  backslash-escape
                      sequences by default.
       s\bsu\bus\bsp\bpe\ben\bnd\bd [-\b-f\bf]
              Suspend the execution of this shell until it receives a  S\bSI\bIG\bGC\bCO\bON\bNT\bT
              signal.  A login shell cannot be suspended; the -\b-f\bf option can be
              used to override this and force the suspension.  The return sta-
              tus  is  0  unless the shell is a login shell and -\b-f\bf is not sup-
              plied, or if job control is not enabled.
       t\bte\bes\bst\bt _\be_\bx_\bp_\br
       [\b[ _\be_\bx_\bp_\br ]\b]
              Return a status of 0 or 1 depending on  the  evaluation  of  the
              conditional  expression _\be_\bx_\bp_\br.  Each operator and operand must be
              a separate argument.  Expressions are composed of the  primaries
              described  above  under  C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS.  t\bte\bes\bst\bt does not
              accept any options, nor does it accept and ignore an argument of
              -\b--\b- as signifying the end of options.

              Expressions  may  be  combined  using  the  following operators,
              listed  in  decreasing  order  of  precedence.   The  evaluation
              depends  on the number of arguments; see below.  Operator prece-
              dence is used when there are five or more arguments.
              !\b! _\be_\bx_\bp_\br True if _\be_\bx_\bp_\br is false.
              (\b( _\be_\bx_\bp_\br )\b)
                     Returns the value of _\be_\bx_\bp_\br.  This may be used to  override
                     the normal precedence of operators.
              _\be_\bx_\bp_\br_\b1 -a\ba _\be_\bx_\bp_\br_\b2
                     True if both _\be_\bx_\bp_\br_\b1 and _\be_\bx_\bp_\br_\b2 are true.
              _\be_\bx_\bp_\br_\b1 -o\bo _\be_\bx_\bp_\br_\b2
                     True if either _\be_\bx_\bp_\br_\b1 or _\be_\bx_\bp_\br_\b2 is true.

              t\bte\bes\bst\bt and [\b[ 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 !\b!, 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 C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS,  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
                     The following conditions are applied in the order listed.
                     If the second argument is one of the  binary  conditional
                     operators listed above under C\bCO\bON\bND\bDI\bIT\bTI\bIO\bON\bNA\bAL\bL E\bEX\bXP\bPR\bRE\bES\bSS\bSI\bIO\bON\bNS\bS, the
                     result of the expression is the result of the binary test
                     using  the first and third arguments as operands.  The -\b-a\ba
                     and -\b-o\bo operators are  considered  binary  operators  when
                     there  are  three arguments.  If the first argument is !\b!,
                     the value is the negation of the two-argument test  using
                     the second and third arguments.  If the first argument is
                     exactly (\b( and the third argument is exactly )\b), the result
                     is  the one-argument test of the second argument.  Other-
                     wise, the expression is false.
              4 arguments
                     If the first argument is !\b!, 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.

              When  used  with  t\bte\bes\bst\bt  or [\b[, the <\b< and >\b> operators sort lexico-
              graphically using ASCII ordering.

       t\bti\bim\bme\bes\bs  Print the accumulated user and system times for  the  shell  and
              for processes run from the shell.  The return status is 0.

       t\btr\bra\bap\bp [-\b-l\blp\bp] [[_\ba_\br_\bg] _\bs_\bi_\bg_\bs_\bp_\be_\bc ...]
              The  command  _\ba_\br_\bg  is  to  be  read  and executed when the shell
              receives signal(s) _\bs_\bi_\bg_\bs_\bp_\be_\bc.  If _\ba_\br_\bg is absent (and  there  is  a
              single  _\bs_\bi_\bg_\bs_\bp_\be_\bc)  or  -\b-,  each  specified signal is reset to its
              original disposition (the value it  had  upon  entrance  to  the
              shell).   If _\ba_\br_\bg is the null string the signal specified by each
              _\bs_\bi_\bg_\bs_\bp_\be_\bc is ignored by the shell and by the commands it  invokes.
              If  _\ba_\br_\bg  is  not present and -\b-p\bp has been supplied, then the trap
              commands associated with each  _\bs_\bi_\bg_\bs_\bp_\be_\bc  are  displayed.   If  no
              arguments  are  supplied or if only -\b-p\bp is given, t\btr\bra\bap\bp prints the
              list of commands associated with each  signal.   The  -\b-l\bl  option
              causes  the shell to print a list of signal names and their cor-
              responding numbers.   Each  _\bs_\bi_\bg_\bs_\bp_\be_\bc  is  either  a  signal  name
              defined  in  <_\bs_\bi_\bg_\bn_\ba_\bl_\b._\bh>,  or  a signal number.  Signal names are
              case insensitive and the S\bSI\bIG\bG prefix is optional.

              If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bEX\bXI\bIT\bT (0) the command _\ba_\br_\bg  is  executed  on  exit
              from  the shell.  If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is D\bDE\bEB\bBU\bUG\bG, the command _\ba_\br_\bg is exe-
              cuted before every _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd, _\bf_\bo_\br  command,  _\bc_\ba_\bs_\be  command,
              _\bs_\be_\bl_\be_\bc_\bt  command,  every  arithmetic  _\bf_\bo_\br command, and before the
              first command executes in a shell function  (see  S\bSH\bHE\bEL\bLL\bL  G\bGR\bRA\bAM\bMM\bMA\bAR\bR
              above).   Refer to the description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the
              s\bsh\bho\bop\bpt\bt builtin for details of its effect on the D\bDE\bEB\bBU\bUG\bG trap.  If a
              _\bs_\bi_\bg_\bs_\bp_\be_\bc is R\bRE\bET\bTU\bUR\bRN\bN, the command _\ba_\br_\bg is executed each time a shell
              function or a script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins fin-
              ishes executing.

              If a _\bs_\bi_\bg_\bs_\bp_\be_\bc is E\bER\bRR\bR, the command _\ba_\br_\bg is executed whenever a sim-
              ple command has a non-zero exit status, subject to the following
              conditions.   The E\bER\bRR\bR trap is not executed if the failed command
              is part of the command list immediately  following  a  w\bwh\bhi\bil\ble\be  or
              u\bun\bnt\bti\bil\bl  keyword,  part  of the test in an _\bi_\bf statement, part of a
              command executed in a &\b&&\b& or |\b||\b| list, or if the command's  return
              value  is  being  inverted via !\b!.  These are the same conditions
              obeyed by the e\ber\brr\bre\bex\bxi\bit\bt option.

              Signals ignored upon entry to the shell  cannot  be  trapped  or
              reset.   Trapped signals that are not being ignored are reset to
              their original values in a subshell or subshell environment when
              one  is  created.   The return status is false if any _\bs_\bi_\bg_\bs_\bp_\be_\bc is
              invalid; otherwise t\btr\bra\bap\bp returns true.

       t\bty\byp\bpe\be [-\b-a\baf\bft\btp\bpP\bP] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
              With no options, indicate how each _\bn_\ba_\bm_\be would be interpreted  if
              used as a command name.  If the -\b-t\bt option is used, t\bty\byp\bpe\be prints a
              string which is one of _\ba_\bl_\bi_\ba_\bs,  _\bk_\be_\by_\bw_\bo_\br_\bd,  _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn,  _\bb_\bu_\bi_\bl_\bt_\bi_\bn,  or
              _\bf_\bi_\bl_\be  if  _\bn_\ba_\bm_\be  is  an  alias,  shell  reserved  word, function,
              builtin, or disk file, respectively.  If the _\bn_\ba_\bm_\be is not  found,
              then  nothing  is  printed,  and  an  exit  status  of  false is
              returned.  If the -\b-p\bp option is used,  t\bty\byp\bpe\be  either  returns  the
              name of the disk file that would be executed if _\bn_\ba_\bm_\be were speci-
              fied as a command name, or nothing if ``type -t name'' would not
              return  _\bf_\bi_\bl_\be.  The -\b-P\bP option forces a P\bPA\bAT\bTH\bH search for each _\bn_\ba_\bm_\be,
              even if ``type -t name'' would not return _\bf_\bi_\bl_\be.  If a command is
              hashed,  -\b-p\bp  and  -\b-P\bP print the hashed value, not necessarily the
              file that appears first in P\bPA\bAT\bTH\bH.  If the -\b-a\ba option is used, t\bty\byp\bpe\be
              prints  all of the places that contain an executable named _\bn_\ba_\bm_\be.
              This includes aliases and functions,  if  and  only  if  the  -\b-p\bp
              option  is  not  also used.  The table of hashed commands is not
              consulted when using -\b-a\ba.  The -\b-f\bf option suppresses  shell  func-
              tion  lookup, as with the c\bco\bom\bmm\bma\ban\bnd\bd builtin.  t\bty\byp\bpe\be returns true if
              all of the arguments are found, false if any are not found.

       u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bST\bTa\bab\bbc\bcd\bde\bef\bfi\bil\blm\bmn\bnp\bpq\bqr\brs\bst\btu\buv\bvx\bx [_\bl_\bi_\bm_\bi_\bt]]
              Provides control over the resources available to the  shell  and
              to  processes started by it, on systems that allow such control.
              The -\b-H\bH and -\b-S\bS options specify that the hard or soft limit is set
              for  the  given resource.  A hard limit cannot be increased by a
              non-root user once it is set; a soft limit may be  increased  up
              to  the value of the hard limit.  If neither -\b-H\bH nor -\b-S\bS is speci-
              fied, both the soft and hard limits are set.  The value of _\bl_\bi_\bm_\bi_\bt
              can be a number in the unit specified for the resource or one of
              the special values h\bha\bar\brd\bd, s\bso\bof\bft\bt, or u\bun\bnl\bli\bim\bmi\bit\bte\bed\bd, which stand for the
              current  hard  limit,  the  current  soft  limit,  and no limit,
              respectively.  If _\bl_\bi_\bm_\bi_\bt is omitted, the  current  value  of  the
              soft  limit  of the resource is printed, unless the -\b-H\bH option is
              given.  When more than one resource is specified, the limit name
              and unit are printed before the value.  Other options are inter-
              preted as follows:
              -\b-a\ba     All current limits are reported
              -\b-b\bb     The maximum socket buffer size
              -\b-c\bc     The maximum size of core files created
              -\b-d\bd     The maximum size of a process's data segment
              -\b-e\be     The maximum scheduling priority ("nice")
              -\b-f\bf     The maximum size of files written by the  shell  and  its
                     children
              -\b-i\bi     The maximum number of pending signals
              -\b-l\bl     The maximum size that may be locked into memory
              -\b-m\bm     The  maximum resident set size (many systems do not honor
                     this limit)
              -\b-n\bn     The maximum number of open file descriptors (most systems
                     do not allow this value to be set)
              -\b-p\bp     The pipe size in 512-byte blocks (this may not be set)
              -\b-q\bq     The maximum number of bytes in POSIX message queues
              -\b-r\br     The maximum real-time scheduling priority
              -\b-s\bs     The maximum stack size
              -\b-t\bt     The maximum amount of cpu time in seconds
              -\b-u\bu     The  maximum  number  of  processes available to a single
                     user
              -\b-v\bv     The maximum amount of virtual  memory  available  to  the
                     shell and, on some systems, to its children
              -\b-x\bx     The maximum number of file locks
              -\b-T\bT     The maximum number of threads

              If _\bl_\bi_\bm_\bi_\bt is given, it is the new value of the specified resource
              (the -\b-a\ba option is display only).  If no option is given, then -\b-f\bf
              is  assumed.  Values are in 1024-byte increments, except for -\b-t\bt,
              which is in seconds, -\b-p\bp, which is in units of  512-byte  blocks,
              and  -\b-T\bT,  -\b-b\bb, -\b-n\bn, and -\b-u\bu, 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.

       u\bum\bma\bas\bsk\bk [-\b-p\bp] [-\b-S\bS] [_\bm_\bo_\bd_\be]
              The user file-creation mask is set to _\bm_\bo_\bd_\be.  If _\bm_\bo_\bd_\be 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
              _\bc_\bh_\bm_\bo_\bd(1).  If _\bm_\bo_\bd_\be is omitted, the current value of the mask  is
              printed.   The  -\b-S\bS  option causes the mask to be printed in sym-
              bolic form; the default output is an octal number.   If  the  -\b-p\bp
              option is supplied, and _\bm_\bo_\bd_\be 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 _\bm_\bo_\bd_\be argument was supplied,
              and false otherwise.

       u\bun\bna\bal\bli\bia\bas\bs [-a\ba] [_\bn_\ba_\bm_\be ...]
              Remove each _\bn_\ba_\bm_\be from the list of defined  aliases.   If  -\b-a\ba  is
              supplied,  all  alias definitions are removed.  The return value
              is true unless a supplied _\bn_\ba_\bm_\be is not a defined alias.

       u\bun\bns\bse\bet\bt [-f\bfv\bv] [_\bn_\ba_\bm_\be ...]
              For each _\bn_\ba_\bm_\be, remove the corresponding  variable  or  function.
              If no options are supplied, or the -\b-v\bv option is given, each _\bn_\ba_\bm_\be
              refers to a shell variable.   Read-only  variables  may  not  be
              unset.   If  -\b-f\bf  is specified, each _\bn_\ba_\bm_\be 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 C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS,  R\bRA\bAN\bND\bDO\bOM\bM,  S\bSE\bEC\bCO\bON\bND\bDS\bS,
              L\bLI\bIN\bNE\bEN\bNO\bO,  H\bHI\bIS\bST\bTC\bCM\bMD\bD,  F\bFU\bUN\bNC\bCN\bNA\bAM\bME\bE, G\bGR\bRO\bOU\bUP\bPS\bS, or D\bDI\bIR\bRS\bST\bTA\bAC\bCK\bK are unset, they
              lose their special properties, even  if  they  are  subsequently
              reset.  The exit status is true unless a _\bn_\ba_\bm_\be is readonly.

       w\bwa\bai\bit\bt [_\bn _\b._\b._\b.]
              Wait  for each specified process and return its termination sta-
              tus.  Each _\bn 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 _\bn is not given, all currently active child  pro-
              cesses  are  waited  for,  and  the return status is zero.  If _\bn
              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.

S\bSE\bEE\bE A\bAL\bLS\bSO\bO
       bash(1), sh(1)



GNU Bash-4.0                      2004 Apr 20                 BASH_BUILTINS(1)