doc/builtins.0

   1 BASH_BUILTINS(1)            General Commands Manual           BASH_BUILTINS(1)
   2
   3
   4
   5 N\bNA\bAM\bME\bE
   6        bash,  :,  .,  [, alias, bg, bind, break, builtin, caller, cd, command,
   7        compgen, complete, compopt,  continue,  declare,  dirs,  disown,  echo,
   8        enable,  eval,  exec, exit, export, false, fc, fg, getopts, hash, help,
   9        history, jobs, kill, let, local, logout, mapfile, popd, printf,  pushd,
  10        pwd,  read, readonly, return, set, shift, shopt, source, suspend, test,
  11        times, trap, true, type, typeset, ulimit, umask, unalias, unset, wait -
  12        bash built-in commands, see b\bba\bas\bsh\bh(1)
  13
  14 B\bBA\bAS\bSH\bH B\bBU\bUI\bIL\bLT\bTI\bIN\bN C\bCO\bOM\bMM\bMA\bAN\bND\bDS\bS
  15        Unless otherwise noted, each builtin command documented in this section
  16        as accepting options preceded by -\b- accepts -\b--\b- to signify the end of the
  17        options.  The :\b:, t\btr\bru\bue\be, f\bfa\bal\bls\bse\be, and t\bte\bes\bst\bt/[\b[ builtins do not accept options
  18        and do not treat -\b--\b- specially.  The e\bex\bxi\bit\bt, l\blo\bog\bgo\bou\but\bt, r\bre\bet\btu\bur\brn\bn,  b\bbr\bre\bea\bak\bk,  c\bco\bon\bn-\b-
  19        t\bti\bin\bnu\bue\be,  l\ble\bet\bt,  and s\bsh\bhi\bif\bft\bt builtins accept and process arguments beginning
  20        with -\b- without requiring -\b--\b-.  Other builtins that accept arguments  but
  21        are  not  specified  as accepting options interpret arguments beginning
  22        with -\b- as invalid options and require -\b--\b- to  prevent  this  interpreta-
  23        tion.
  24        :\b: [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
  25               No  effect;  the command does nothing beyond expanding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs
  26               and performing any specified redirections.  The return status is
  27               zero.
  28
  29         .\b.  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
  30        s\bso\bou\bur\brc\bce\be _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be [_\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs]
  31               Read  and  execute  commands  from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be in the current shell
  32               environment and return the exit status of the last command  exe-
  33               cuted  from  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be.   If  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  does not contain a slash,
  34               filenames in P\bPA\bAT\bTH\bH are used  to  find  the  directory  containing
  35               _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be.  The file searched for in P\bPA\bAT\bTH\bH need not be executable.
  36               When b\bba\bas\bsh\bh is  not  in  _\bp_\bo_\bs_\bi_\bx  _\bm_\bo_\bd_\be,  the  current  directory  is
  37               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
  38               to the s\bsh\bho\bop\bpt\bt builtin command is turned  off,  the  P\bPA\bAT\bTH\bH  is  not
  39               searched.   If any _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs are supplied, they become the posi-
  40               tional parameters when  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  is  executed.   Otherwise  the
  41               positional  parameters  are  unchanged.   If  the  -\b-T\bT  option is
  42               enabled, s\bso\bou\bur\brc\bce\be inherits any trap on D\bDE\bEB\bBU\bUG\bG; if it  is  not,  any
  43               D\bDE\bEB\bBU\bUG\bG  trap  string  is  saved  and  restored around the call to
  44               s\bso\bou\bur\brc\bce\be, and s\bso\bou\bur\brc\bce\be unsets the D\bDE\bEB\bBU\bUG\bG trap while it executes.   If
  45               -\b-T\bT  is not set, and the sourced file changes the D\bDE\bEB\bBU\bUG\bG trap, the
  46               new value is retained when s\bso\bou\bur\brc\bce\be completes.  The return  status
  47               is the status of the last command exited within the script (0 if
  48               no commands are executed), and false if _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be is not found or
  49               cannot be read.
  50
  51        a\bal\bli\bia\bas\bs [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
  52               A\bAl\bli\bia\bas\bs with no arguments or with the -\b-p\bp option prints the list of
  53               aliases in the form a\bal\bli\bia\bas\bs _\bn_\ba_\bm_\be=_\bv_\ba_\bl_\bu_\be on standard  output.   When
  54               arguments  are supplied, an alias is defined for each _\bn_\ba_\bm_\be whose
  55               _\bv_\ba_\bl_\bu_\be is given.  A trailing space in _\bv_\ba_\bl_\bu_\be causes the next  word
  56               to be checked for alias substitution when the alias is expanded.
  57               For each _\bn_\ba_\bm_\be in the argument list for which no  _\bv_\ba_\bl_\bu_\be  is  sup-
  58               plied,  the  name  and  value  of  the  alias is printed.  A\bAl\bli\bia\bas\bs
  59               returns true unless a _\bn_\ba_\bm_\be is given for which no alias has  been
  60               defined.
  61
  62        b\bbg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc ...]
  63               Resume  each  suspended  job _\bj_\bo_\bb_\bs_\bp_\be_\bc in the background, as if it
  64               had been started with &\b&.  If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, the shell's
  65               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
  66               run when job control is disabled or, when run with  job  control
  67               enabled,  any  specified  _\bj_\bo_\bb_\bs_\bp_\be_\bc  was  not found or was started
  68               without job control.
  69
  70        b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] [-\b-l\blp\bps\bsv\bvP\bPS\bSV\bVX\bX]
  71        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]
  72        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
  73        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
  74        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
  75        b\bbi\bin\bnd\bd [-\b-m\bm _\bk_\be_\by_\bm_\ba_\bp] _\bk_\be_\by_\bs_\be_\bq:_\br_\be_\ba_\bd_\bl_\bi_\bn_\be_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
  76               Display current r\bre\bea\bad\bdl\bli\bin\bne\be key and function bindings, bind  a  key
  77               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
  78               variable.  Each non-option argument is a  command  as  it  would
  79               appear  in  _\b._\bi_\bn_\bp_\bu_\bt_\br_\bc, but each binding or command must be passed
  80               as a separate argument; e.g.,  '"\C-x\C-r":  re-read-init-file'.
  81               Options, if supplied, have the following meanings:
  82               -\b-m\bm _\bk_\be_\by_\bm_\ba_\bp
  83                      Use _\bk_\be_\by_\bm_\ba_\bp as the keymap to be affected by the subsequent
  84                      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-
  85                      _\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,
  86                      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  (_\bv_\bi_\b-_\bm_\bo_\bv_\be
  87                      is  also  a  synonym); _\be_\bm_\ba_\bc_\bs is equivalent to _\be_\bm_\ba_\bc_\bs_\b-_\bs_\bt_\ba_\bn_\b-
  88                      _\bd_\ba_\br_\bd.
  89               -\b-l\bl     List the names of all r\bre\bea\bad\bdl\bli\bin\bne\be functions.
  90               -\b-p\bp     Display r\bre\bea\bad\bdl\bli\bin\bne\be function names and bindings  in  such  a
  91                      way that they can be re-read.
  92               -\b-P\bP     List current r\bre\bea\bad\bdl\bli\bin\bne\be function names and bindings.
  93               -\b-s\bs     Display  r\bre\bea\bad\bdl\bli\bin\bne\be  key  sequences bound to macros and the
  94                      strings they output in such a way that they  can  be  re-
  95                      read.
  96               -\b-S\bS     Display  r\bre\bea\bad\bdl\bli\bin\bne\be  key  sequences bound to macros and the
  97                      strings they output.
  98               -\b-v\bv     Display r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values in such a  way
  99                      that they can be re-read.
 100               -\b-V\bV     List current r\bre\bea\bad\bdl\bli\bin\bne\be variable names and values.
 101               -\b-f\bf _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
 102                      Read key bindings from _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be.
 103               -\b-q\bq _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
 104                      Query about which keys invoke the named _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn.
 105               -\b-u\bu _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
 106                      Unbind all keys bound to the named _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn.
 107               -\b-r\br _\bk_\be_\by_\bs_\be_\bq
 108                      Remove any current binding for _\bk_\be_\by_\bs_\be_\bq.
 109               -\b-x\bx _\bk_\be_\by_\bs_\be_\bq:\b:_\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd
 110                      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
 111                      entered.  When _\bs_\bh_\be_\bl_\bl_\b-_\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed, the shell  sets
 112                      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-
 113                      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
 114                      current location of the insertion point.  If the executed
 115                      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-
 116                      L\bLI\bIN\bNE\bE_\b_P\bPO\bOI\bIN\bNT\bT,  those  new  values  will be reflected in the
 117                      editing state.
 118               -\b-X\bX     List all key sequences bound to shell  commands  and  the
 119                      associated  commands  in  a  format that can be reused as
 120                      input.
 121
 122               The return value is 0 unless an unrecognized option is given  or
 123               an error occurred.
 124
 125        b\bbr\bre\bea\bak\bk [_\bn]
 126               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
 127               specified, break _\bn levels.  _\bn must be >= 1.   If  _\bn  is  greater
 128               than  the  number  of  enclosing  loops, all enclosing loops are
 129               exited.  The return value is 0 unless _\bn is not greater  than  or
 130               equal to 1.
 131
 132        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]
 133               Execute  the  specified shell builtin, passing it _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs, and
 134               return its exit status.  This is useful when defining a function
 135               whose  name  is the same as a shell builtin, retaining the func-
 136               tionality of the builtin within the function.  The c\bcd\bd builtin is
 137               commonly  redefined  this  way.   The  return status is false if
 138               _\bs_\bh_\be_\bl_\bl_\b-_\bb_\bu_\bi_\bl_\bt_\bi_\bn is not a shell builtin command.
 139
 140        c\bca\bal\bll\ble\ber\br [_\be_\bx_\bp_\br]
 141               Returns the context of any active subroutine call (a shell func-
 142               tion or a script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins).  With-
 143               out _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number and source filename of
 144               the  current subroutine call.  If a non-negative integer is sup-
 145               plied as _\be_\bx_\bp_\br, c\bca\bal\bll\ble\ber\br displays the line number, subroutine name,
 146               and  source  file  corresponding to that position in the current
 147               execution call stack.  This extra information may be  used,  for
 148               example,  to print a stack trace.  The current frame is frame 0.
 149               The return value is 0 unless the shell is not executing  a  sub-
 150               routine  call or _\be_\bx_\bp_\br does not correspond to a valid position in
 151               the call stack.
 152
 153        c\bcd\bd [-\b-L\bL|[-\b-P\bP [-\b-e\be]] [-@]] [_\bd_\bi_\br]
 154               Change the current directory to _\bd_\bi_\br.  if _\bd_\bi_\br  is  not  supplied,
 155               the  value of the H\bHO\bOM\bME\bE shell variable is the default.  Any addi-
 156               tional arguments following _\bd_\bi_\br are ignored.  The variable C\bCD\bDP\bPA\bAT\bTH\bH
 157               defines  the  search path for the directory containing _\bd_\bi_\br: each
 158               directory name in  C\bCD\bDP\bPA\bAT\bTH\bH  is  searched  for  _\bd_\bi_\br.   Alternative
 159               directory  names in C\bCD\bDP\bPA\bAT\bTH\bH are separated by a colon (:).  A null
 160               directory name in C\bCD\bDP\bPA\bAT\bTH\bH is the same as the  current  directory,
 161               i.e., ``.\b.''.  If _\bd_\bi_\br begins with a slash (/), then C\bCD\bDP\bPA\bAT\bTH\bH is not
 162               used.  The -\b-P\bP option causes c\bcd\bd to  use  the  physical  directory
 163               structure  by  resolving symbolic links while traversing _\bd_\bi_\br and
 164               before processing instances of _\b._\b. in _\bd_\bi_\br (see also the -\b-P\bP option
 165               to the s\bse\bet\bt builtin command); the -\b-L\bL option forces symbolic links
 166               to be followed by resolving the link after processing  instances
 167               of _\b._\b. in _\bd_\bi_\br.  If _\b._\b. appears in _\bd_\bi_\br, it is processed by removing
 168               the immediately previous pathname component from _\bd_\bi_\br, back to  a
 169               slash  or  the  beginning  of _\bd_\bi_\br.  If the -\b-e\be option is supplied
 170               with -\b-P\bP, and the current working directory  cannot  be  success-
 171               fully  determined  after  a successful directory change, c\bcd\bd will
 172               return an unsuccessful status.  On systems that support it,  the
 173               -\b-@\b@  option  presents  the  extended attributes associated with a
 174               file as a directory.  An argument of -\b- is converted  to  $\b$O\bOL\bLD\bDP\bPW\bWD\bD
 175               before the directory change is attempted.  If a non-empty direc-
 176               tory name from C\bCD\bDP\bPA\bAT\bTH\bH is used, or if -\b- is  the  first  argument,
 177               and the directory change is successful, the absolute pathname of
 178               the new working directory is written  to  the  standard  output.
 179               The  return  value  is  true  if  the directory was successfully
 180               changed; false otherwise.
 181
 182        c\bco\bom\bmm\bma\ban\bnd\bd [-\b-p\bpV\bVv\bv] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\ba_\br_\bg ...]
 183               Run _\bc_\bo_\bm_\bm_\ba_\bn_\bd with _\ba_\br_\bg_\bs  suppressing  the  normal  shell  function
 184               lookup.  Only builtin commands or commands found in the P\bPA\bAT\bTH\bH are
 185               executed.  If the -\b-p\bp option is given, the search for _\bc_\bo_\bm_\bm_\ba_\bn_\bd  is
 186               performed  using  a default value for P\bPA\bAT\bTH\bH that is guaranteed to
 187               find all of the standard utilities.  If  either  the  -\b-V\bV  or  -\b-v\bv
 188               option is supplied, a description of _\bc_\bo_\bm_\bm_\ba_\bn_\bd is printed.  The -\b-v\bv
 189               option causes a single word indicating the command  or  filename
 190               used to invoke _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be displayed; the -\b-V\bV option produces a
 191               more verbose description.  If the -\b-V\bV or -\b-v\bv option  is  supplied,
 192               the  exit  status  is  0 if _\bc_\bo_\bm_\bm_\ba_\bn_\bd was found, and 1 if not.  If
 193               neither option is supplied and an error occurred or _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
 194               not  be found, the exit status is 127.  Otherwise, the exit sta-
 195               tus of the c\bco\bom\bmm\bma\ban\bnd\bd builtin is the exit status of _\bc_\bo_\bm_\bm_\ba_\bn_\bd.
 196
 197        c\bco\bom\bmp\bpg\bge\ben\bn [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bw_\bo_\br_\bd]
 198               Generate possible completion matches for _\bw_\bo_\br_\bd according  to  the
 199               _\bo_\bp_\bt_\bi_\bo_\bns,  which  may  be  any  option  accepted  by the c\bco\bom\bmp\bpl\ble\bet\bte\be
 200               builtin with the exception of -\b-p\bp and -\b-r\br, and write  the  matches
 201               to  the  standard  output.  When using the -\b-F\bF or -\b-C\bC options, the
 202               various shell  variables  set  by  the  programmable  completion
 203               facilities, while available, will not have useful values.
 204
 205               The matches will be generated in the same way as if the program-
 206               mable completion code had generated them directly from a comple-
 207               tion  specification  with the same flags.  If _\bw_\bo_\br_\bd is specified,
 208               only those completions matching _\bw_\bo_\br_\bd will be displayed.
 209
 210               The return value is true unless an invalid option  is  supplied,
 211               or no matches were generated.
 212
 213        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\bEI\bI] [-\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn] [-\b-G\bG _\bg_\bl_\bo_\bb_\b-
 214        _\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]
 215               [-\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.]
 216        c\bco\bom\bmp\bpl\ble\bet\bte\be -\b-p\bpr\br [-\b-D\bDE\bEI\bI] [_\bn_\ba_\bm_\be ...]
 217               Specify how arguments to each _\bn_\ba_\bm_\be should be completed.  If  the
 218               -\b-p\bp  option  is supplied, or if no options are supplied, existing
 219               completion specifications are printed in a way that allows  them
 220               to be reused as input.  The -\b-r\br option removes a completion spec-
 221               ification for each _\bn_\ba_\bm_\be, or, if no _\bn_\ba_\bm_\bes are supplied, all  com-
 222               pletion specifications.  The -\b-D\bD option indicates that other sup-
 223               plied options and actions should apply to the  ``default''  com-
 224               mand  completion; that is, completion attempted on a command for
 225               which no completion has previously been defined.  The -\b-E\bE  option
 226               indicates  that  other supplied options and actions should apply
 227               to ``empty'' command completion; that is,  completion  attempted
 228               on  a  blank  line.  The -\b-I\bI option indicates that other supplied
 229               options and actions should apply to  completion  on  the  inital
 230               non-assignment  word  on  the line, or after a command delimiter
 231               such as ;\b; or |\b|, which is usually command  name  completion.   If
 232               multiple  options  are  supplied, the -\b-D\bD option takes precedence
 233               over -\b-E\bE, and both take precedence over -\b-I\bI.  If any of -\b-D\bD, -\b-E\bE, or
 234               -\b-I\bI  are  supplied,  any  other _\bn_\ba_\bm_\be arguments are ignored; these
 235               completions only apply to the case specified by the option.
 236
 237               The process of applying  these  completion  specifications  when
 238               word  completion  is attempted is described above under P\bPr\bro\bog\bgr\bra\bam\bm-\b-
 239               m\bma\bab\bbl\ble\be C\bCo\bom\bmp\bpl\ble\bet\bti\bio\bon\bn.
 240
 241               Other options, if specified, have the following  meanings.   The
 242               arguments  to the -\b-G\bG, -\b-W\bW, and -\b-X\bX options (and, if necessary, the
 243               -\b-P\bP and -\b-S\bS options) should be quoted to protect them from  expan-
 244               sion before the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin is invoked.
 245               -\b-o\bo _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn
 246                       The  _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn  controls  several aspects of the comp-
 247                       spec's behavior beyond the simple generation of  comple-
 248                       tions.  _\bc_\bo_\bm_\bp_\b-_\bo_\bp_\bt_\bi_\bo_\bn may be one of:
 249                       b\bba\bas\bsh\bhd\bde\bef\bfa\bau\bul\blt\bt
 250                               Perform the rest of the default b\bba\bas\bsh\bh completions
 251                               if the compspec generates no matches.
 252                       d\bde\bef\bfa\bau\bul\blt\bt Use readline's default  filename  completion  if
 253                               the compspec generates no matches.
 254                       d\bdi\bir\brn\bna\bam\bme\bes\bs
 255                               Perform  directory  name completion if the comp-
 256                               spec generates no matches.
 257                       f\bfi\bil\ble\ben\bna\bam\bme\bes\bs
 258                               Tell readline that the compspec generates  file-
 259                               names,  so  it can perform any filename-specific
 260                               processing (like adding  a  slash  to  directory
 261                               names,  quoting special characters, or suppress-
 262                               ing trailing spaces).  Intended to be used  with
 263                               shell functions.
 264                       n\bno\boq\bqu\buo\bot\bte\be Tell  readline  not to quote the completed words
 265                               if they are filenames (quoting filenames is  the
 266                               default).
 267                       n\bno\bos\bso\bor\brt\bt  Tell  readline  not to sort the list of possible
 268                               completions alphabetically.
 269                       n\bno\bos\bsp\bpa\bac\bce\be Tell  readline  not  to  append  a  space   (the
 270                               default)  to  words  completed at the end of the
 271                               line.
 272                       p\bpl\blu\bus\bsd\bdi\bir\brs\bs
 273                               After any matches defined by  the  compspec  are
 274                               generated,    directory   name   completion   is
 275                               attempted and  any  matches  are  added  to  the
 276                               results of the other actions.
 277               -\b-A\bA _\ba_\bc_\bt_\bi_\bo_\bn
 278                       The  _\ba_\bc_\bt_\bi_\bo_\bn  may  be  one of the following to generate a
 279                       list of possible completions:
 280                       a\bal\bli\bia\bas\bs   Alias names.  May also be specified as -\b-a\ba.
 281                       a\bar\brr\bra\bay\byv\bva\bar\br
 282                               Array variable names.
 283                       b\bbi\bin\bnd\bdi\bin\bng\bg R\bRe\bea\bad\bdl\bli\bin\bne\be key binding names.
 284                       b\bbu\bui\bil\blt\bti\bin\bn Names of shell builtin commands.   May  also  be
 285                               specified as -\b-b\bb.
 286                       c\bco\bom\bmm\bma\ban\bnd\bd Command names.  May also be specified as -\b-c\bc.
 287                       d\bdi\bir\bre\bec\bct\bto\bor\bry\by
 288                               Directory names.  May also be specified as -\b-d\bd.
 289                       d\bdi\bis\bsa\bab\bbl\ble\bed\bd
 290                               Names of disabled shell builtins.
 291                       e\ben\bna\bab\bbl\ble\bed\bd Names of enabled shell builtins.
 292                       e\bex\bxp\bpo\bor\brt\bt  Names  of exported shell variables.  May also be
 293                               specified as -\b-e\be.
 294                       f\bfi\bil\ble\be    File names.  May also be specified as -\b-f\bf.
 295                       f\bfu\bun\bnc\bct\bti\bio\bon\bn
 296                               Names of shell functions.
 297                       g\bgr\bro\bou\bup\bp   Group names.  May also be specified as -\b-g\bg.
 298                       h\bhe\bel\blp\bpt\bto\bop\bpi\bic\bc
 299                               Help topics as accepted by the h\bhe\bel\blp\bp builtin.
 300                       h\bho\bos\bst\btn\bna\bam\bme\be
 301                               Hostnames, as taken from the file  specified  by
 302                               the H\bHO\bOS\bST\bTF\bFI\bIL\bLE\bE shell variable.
 303                       j\bjo\bob\bb     Job  names,  if job control is active.  May also
 304                               be specified as -\b-j\bj.
 305                       k\bke\bey\byw\bwo\bor\brd\bd Shell reserved words.  May also be specified  as
 306                               -\b-k\bk.
 307                       r\bru\bun\bnn\bni\bin\bng\bg Names of running jobs, if job control is active.
 308                       s\bse\ber\brv\bvi\bic\bce\be Service names.  May also be specified as -\b-s\bs.
 309                       s\bse\bet\bto\bop\bpt\bt  Valid  arguments  for  the  -\b-o\bo option to the s\bse\bet\bt
 310                               builtin.
 311                       s\bsh\bho\bop\bpt\bt   Shell option names  as  accepted  by  the  s\bsh\bho\bop\bpt\bt
 312                               builtin.
 313                       s\bsi\big\bgn\bna\bal\bl  Signal names.
 314                       s\bst\bto\bop\bpp\bpe\bed\bd Names of stopped jobs, if job control is active.
 315                       u\bus\bse\ber\br    User names.  May also be specified as -\b-u\bu.
 316                       v\bva\bar\bri\bia\bab\bbl\ble\be
 317                               Names of all shell variables.  May also be spec-
 318                               ified as -\b-v\bv.
 319               -\b-C\bC _\bc_\bo_\bm_\bm_\ba_\bn_\bd
 320                       _\bc_\bo_\bm_\bm_\ba_\bn_\bd is executed in a subshell environment,  and  its
 321                       output is used as the possible completions.
 322               -\b-F\bF _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn
 323                       The  shell  function _\bf_\bu_\bn_\bc_\bt_\bi_\bo_\bn is executed in the current
 324                       shell environment.  When the function is  executed,  the
 325                       first  argument  ($\b$1\b1)  is  the name of the command whose
 326                       arguments are being completed, the second argument  ($\b$2\b2)
 327                       is the word being completed, and the third argument ($\b$3\b3)
 328                       is the word preceding the word being  completed  on  the
 329                       current  command  line.   When it finishes, the possible
 330                       completions are retrieved from the value of the  C\bCO\bOM\bMP\bPR\bRE\bE-\b-
 331                       P\bPL\bLY\bY array variable.
 332               -\b-G\bG _\bg_\bl_\bo_\bb_\bp_\ba_\bt
 333                       The  pathname  expansion  pattern _\bg_\bl_\bo_\bb_\bp_\ba_\bt is expanded to
 334                       generate the possible completions.
 335               -\b-P\bP _\bp_\br_\be_\bf_\bi_\bx
 336                       _\bp_\br_\be_\bf_\bi_\bx is added at the beginning of each  possible  com-
 337                       pletion after all other options have been applied.
 338               -\b-S\bS _\bs_\bu_\bf_\bf_\bi_\bx
 339                       _\bs_\bu_\bf_\bf_\bi_\bx is appended to each possible completion after all
 340                       other options have been applied.
 341               -\b-W\bW _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt
 342                       The _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt is split using the characters  in  the  I\bIF\bFS\bS
 343                       special  variable as delimiters, and each resultant word
 344                       is expanded.  Shell quoting is honored within  _\bw_\bo_\br_\bd_\bl_\bi_\bs_\bt,
 345                       in order to provide a mechanism for the words to contain
 346                       shell metacharacters or characters in the value of  I\bIF\bFS\bS.
 347                       The  possible  completions are the members of the resul-
 348                       tant list which match the word being completed.
 349               -\b-X\bX _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt
 350                       _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is a pattern as used for  pathname  expansion.
 351                       It is applied to the list of possible completions gener-
 352                       ated by the preceding options and  arguments,  and  each
 353                       completion  matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed from the list.
 354                       A leading !\b! in _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt negates the  pattern;  in  this
 355                       case, any completion not matching _\bf_\bi_\bl_\bt_\be_\br_\bp_\ba_\bt is removed.
 356
 357               The  return  value is true unless an invalid option is supplied,
 358               an option other than -\b-p\bp or -\b-r\br is supplied without a  _\bn_\ba_\bm_\be  argu-
 359               ment,  an  attempt  is made to remove a completion specification
 360               for a _\bn_\ba_\bm_\be for which no specification exists, or an error occurs
 361               adding a completion specification.
 362
 363        c\bco\bom\bmp\bpo\bop\bpt\bt [-\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [-\b-D\bDE\bEI\bI] [+\b+o\bo _\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be]
 364               Modify  completion  options  for  each  _\bn_\ba_\bm_\be  according  to  the
 365               _\bo_\bp_\bt_\bi_\bo_\bns, or for the currently-executing completion if  no  _\bn_\ba_\bm_\bes
 366               are  supplied.   If no _\bo_\bp_\bt_\bi_\bo_\bns are given, display the completion
 367               options for each _\bn_\ba_\bm_\be or the current completion.   The  possible
 368               values  of  _\bo_\bp_\bt_\bi_\bo_\bn  are  those  valid  for  the c\bco\bom\bmp\bpl\ble\bet\bte\be builtin
 369               described above.  The -\b-D\bD option indicates  that  other  supplied
 370               options should apply to the ``default'' command completion; that
 371               is, completion attempted on a command for  which  no  completion
 372               has previously been defined.  The -\b-E\bE option indicates that other
 373               supplied options should apply to ``empty''  command  completion;
 374               that  is,  completion  attempted on a blank line.  The -\b-I\bI option
 375               indicates that other supplied options should apply to completion
 376               on  the  inital non-assignment word on the line, or after a com-
 377               mand delimiter such as ;\b; or |\b|, which  is  usually  command  name
 378               completion.
 379
 380               The  return  value is true unless an invalid option is supplied,
 381               an attempt is made to modify the options for a _\bn_\ba_\bm_\be for which no
 382               completion specification exists, or an output error occurs.
 383
 384        c\bco\bon\bnt\bti\bin\bnu\bue\be [_\bn]
 385               Resume the next iteration of the enclosing f\bfo\bor\br, w\bwh\bhi\bil\ble\be, u\bun\bnt\bti\bil\bl, or
 386               s\bse\bel\ble\bec\bct\bt loop.  If _\bn is specified, resume  at  the  _\bnth  enclosing
 387               loop.   _\bn  must  be  >=  1.   If _\bn is greater than the number of
 388               enclosing loops, the  last  enclosing  loop  (the  ``top-level''
 389               loop) is resumed.  The return value is 0 unless _\bn is not greater
 390               than or equal to 1.
 391
 392        d\bde\bec\bcl\bla\bar\bre\be [-\b-a\baA\bAf\bfF\bFg\bgi\bil\bln\bnr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
 393        t\bty\byp\bpe\bes\bse\bet\bt [-\b-a\baA\bAf\bfF\bFg\bgi\bil\bln\bnr\brt\btu\bux\bx] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ...]
 394               Declare variables and/or give them attributes.  If no _\bn_\ba_\bm_\bes  are
 395               given  then display the values of variables.  The -\b-p\bp option will
 396               display the attributes and values of each _\bn_\ba_\bm_\be.  When -\b-p\bp is used
 397               with  _\bn_\ba_\bm_\be  arguments, additional options, other than -\b-f\bf and -\b-F\bF,
 398               are ignored.  When -\b-p\bp is supplied  without  _\bn_\ba_\bm_\be  arguments,  it
 399               will  display  the attributes and values of all variables having
 400               the attributes specified by the additional options.  If no other
 401               options   are   supplied  with  -\b-p\bp,  d\bde\bec\bcl\bla\bar\bre\be  will  display  the
 402               attributes and values of all shell  variables.   The  -\b-f\bf  option
 403               will  restrict  the  display  to shell functions.  The -\b-F\bF option
 404               inhibits the display of function definitions; only the  function
 405               name  and  attributes are printed.  If the e\bex\bxt\btd\bde\beb\bbu\bug\bg shell option
 406               is enabled using s\bsh\bho\bop\bpt\bt, the source file  name  and  line  number
 407               where each _\bn_\ba_\bm_\be is defined are displayed as well.  The -\b-F\bF option
 408               implies -\b-f\bf.  The -\b-g\bg option forces variables  to  be  created  or
 409               modified at the global scope, even when d\bde\bec\bcl\bla\bar\bre\be is executed in a
 410               shell function.  It is ignored in all other cases.  The  follow-
 411               ing options can be used to restrict output to variables with the
 412               specified attribute or to give variables attributes:
 413               -\b-a\ba     Each _\bn_\ba_\bm_\be  is  an  indexed  array  variable  (see  A\bAr\brr\bra\bay\bys\bs
 414                      above).
 415               -\b-A\bA     Each  _\bn_\ba_\bm_\be  is  an associative array variable (see A\bAr\brr\bra\bay\bys\bs
 416                      above).
 417               -\b-f\bf     Use function names only.
 418               -\b-i\bi     The variable is treated as an integer; arithmetic evalua-
 419                      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
 420                      the variable is assigned a value.
 421               -\b-l\bl     When the variable is assigned  a  value,  all  upper-case
 422                      characters  are  converted to lower-case.  The upper-case
 423                      attribute is disabled.
 424               -\b-n\bn     Give each _\bn_\ba_\bm_\be the _\bn_\ba_\bm_\be_\br_\be_\bf attribute, making  it  a  name
 425                      reference  to  another  variable.  That other variable is
 426                      defined by the value of _\bn_\ba_\bm_\be.   All  references,  assign-
 427                      ments,  and attribute modifications to _\bn_\ba_\bm_\be, except those
 428                      using or changing the -\b-n\bn attribute itself, are  performed
 429                      on  the variable referenced by _\bn_\ba_\bm_\be's value.  The nameref
 430                      attribute cannot be applied to array variables.
 431               -\b-r\br     Make _\bn_\ba_\bm_\bes readonly.  These names cannot then be assigned
 432                      values by subsequent assignment statements or unset.
 433               -\b-t\bt     Give  each  _\bn_\ba_\bm_\be  the  _\bt_\br_\ba_\bc_\be attribute.  Traced functions
 434                      inherit the D\bDE\bEB\bBU\bUG\bG  and  R\bRE\bET\bTU\bUR\bRN\bN  traps  from  the  calling
 435                      shell.   The  trace  attribute has no special meaning for
 436                      variables.
 437               -\b-u\bu     When the variable is assigned  a  value,  all  lower-case
 438                      characters  are  converted to upper-case.  The lower-case
 439                      attribute is disabled.
 440               -\b-x\bx     Mark _\bn_\ba_\bm_\bes for export  to  subsequent  commands  via  the
 441                      environment.
 442
 443               Using  `+'  instead of `-' turns off the attribute instead, with
 444               the exceptions that +\b+a\ba and +\b+A\bA may not be used to  destroy  array
 445               variables  and  +\b+r\br will not remove the readonly attribute.  When
 446               used in a function, d\bde\bec\bcl\bla\bar\bre\be and t\bty\byp\bpe\bes\bse\bet\bt make each _\bn_\ba_\bm_\be local, as
 447               with  the l\blo\boc\bca\bal\bl command, unless the -\b-g\bg option is supplied.  If a
 448               variable name is followed by =_\bv_\ba_\bl_\bu_\be, the value of  the  variable
 449               is  set  to _\bv_\ba_\bl_\bu_\be.  When using -\b-a\ba or -\b-A\bA and the compound assign-
 450               ment syntax to create array variables, additional attributes  do
 451               not  take effect until subsequent assignments.  The return value
 452               is 0 unless an invalid option is encountered, an attempt is made
 453               to define a function using ``-f foo=bar'', an attempt is made to
 454               assign a value to a readonly variable, an  attempt  is  made  to
 455               assign  a  value to an array variable without using the compound
 456               assignment syntax (see A\bAr\brr\bra\bay\bys\bs above), one of the _\bn_\ba_\bm_\be_\bs is not  a
 457               valid  shell variable name, an attempt is made to turn off read-
 458               only status for a readonly variable, an attempt is made to  turn
 459               off array status for an array variable, or an attempt is made to
 460               display a non-existent function with -\b-f\bf.
 461
 462        d\bdi\bir\brs\bs [\b[-\b-c\bcl\blp\bpv\bv]\b] [\b[+\b+_\bn]\b] [\b[-\b-_\bn]\b]
 463               Without options,  displays  the  list  of  currently  remembered
 464               directories.   The  default  display  is  on  a single line with
 465               directory names separated by spaces.  Directories are  added  to
 466               the  list  with  the  p\bpu\bus\bsh\bhd\bd  command;  the  p\bpo\bop\bpd\bd command removes
 467               entries from the list.  The  current  directory  is  always  the
 468               first directory in the stack.
 469               -\b-c\bc     Clears  the  directory  stack  by  deleting  all  of  the
 470                      entries.
 471               -\b-l\bl     Produces a listing  using  full  pathnames;  the  default
 472                      listing format uses a tilde to denote the home directory.
 473               -\b-p\bp     Print the directory stack with one entry per line.
 474               -\b-v\bv     Print  the  directory stack with one entry per line, pre-
 475                      fixing each entry with its index in the stack.
 476               +\b+_\bn     Displays the _\bnth entry counting from the left of the list
 477                      shown by d\bdi\bir\brs\bs when invoked without options, starting with
 478                      zero.
 479               -\b-_\bn     Displays the _\bnth entry counting from  the  right  of  the
 480                      list shown by d\bdi\bir\brs\bs when invoked without options, starting
 481                      with zero.
 482
 483               The return value is 0 unless an invalid option is supplied or  _\bn
 484               indexes beyond the end of the directory stack.
 485
 486        d\bdi\bis\bso\bow\bwn\bn [-\b-a\bar\br] [-\b-h\bh] [_\bj_\bo_\bb_\bs_\bp_\be_\bc ... | _\bp_\bi_\bd ... ]
 487               Without  options,  remove  each _\bj_\bo_\bb_\bs_\bp_\be_\bc from the table of active
 488               jobs.  If _\bj_\bo_\bb_\bs_\bp_\be_\bc is not present, and neither the -\b-a\ba nor the  -\b-r\br
 489               option  is  supplied, the _\bc_\bu_\br_\br_\be_\bn_\bt _\bj_\bo_\bb is used.  If the -\b-h\bh option
 490               is given, each _\bj_\bo_\bb_\bs_\bp_\be_\bc is not removed from  the  table,  but  is
 491               marked  so  that  S\bSI\bIG\bGH\bHU\bUP\bP  is  not  sent  to the job if the shell
 492               receives a S\bSI\bIG\bGH\bHU\bUP\bP.  If no _\bj_\bo_\bb_\bs_\bp_\be_\bc is  supplied,  the  -\b-a\ba  option
 493               means  to  remove or mark all jobs; the -\b-r\br option without a _\bj_\bo_\bb_\b-
 494               _\bs_\bp_\be_\bc argument restricts operation to running jobs.   The  return
 495               value is 0 unless a _\bj_\bo_\bb_\bs_\bp_\be_\bc does not specify a valid job.
 496
 497        e\bec\bch\bho\bo [-\b-n\bne\beE\bE] [_\ba_\br_\bg ...]
 498               Output  the  _\ba_\br_\bgs,  separated  by spaces, followed by a newline.
 499               The return status is 0 unless a write error occurs.   If  -\b-n\bn  is
 500               specified, the trailing newline is suppressed.  If the -\b-e\be option
 501               is given,  interpretation  of  the  following  backslash-escaped
 502               characters  is  enabled.  The -\b-E\bE option disables the interpreta-
 503               tion of these escape characters, even on systems where they  are
 504               interpreted  by  default.  The x\bxp\bpg\bg_\b_e\bec\bch\bho\bo shell option may be used
 505               to dynamically determine  whether  or  not  e\bec\bch\bho\bo  expands  these
 506               escape  characters  by  default.   e\bec\bch\bho\bo does not interpret -\b--\b- to
 507               mean the end of options.  e\bec\bch\bho\bo interprets the  following  escape
 508               sequences:
 509               \\b\a\ba     alert (bell)
 510               \\b\b\bb     backspace
 511               \\b\c\bc     suppress further output
 512               \\b\e\be
 513               \\b\E\bE     an escape character
 514               \\b\f\bf     form feed
 515               \\b\n\bn     new line
 516               \\b\r\br     carriage return
 517               \\b\t\bt     horizontal tab
 518               \\b\v\bv     vertical tab
 519               \\b\\\b\     backslash
 520               \\b\0\b0_\bn_\bn_\bn  the  eight-bit  character  whose value is the octal value
 521                      _\bn_\bn_\bn (zero to three octal digits)
 522               \\b\x\bx_\bH_\bH   the eight-bit character whose value  is  the  hexadecimal
 523                      value _\bH_\bH (one or two hex digits)
 524               \\b\u\bu_\bH_\bH_\bH_\bH the  Unicode (ISO/IEC 10646) character whose value is the
 525                      hexadecimal value _\bH_\bH_\bH_\bH (one to four hex digits)
 526               \\b\U\bU_\bH_\bH_\bH_\bH_\bH_\bH_\bH_\bH
 527                      the Unicode (ISO/IEC 10646) character whose value is  the
 528                      hexadecimal value _\bH_\bH_\bH_\bH_\bH_\bH_\bH_\bH (one to eight hex digits)
 529
 530        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 ...]
 531               Enable  and disable builtin shell commands.  Disabling a builtin
 532               allows a disk command which has the same name as a shell builtin
 533               to  be  executed without specifying a full pathname, even though
 534               the shell normally searches for builtins before  disk  commands.
 535               If  -\b-n\bn  is  used,  each  _\bn_\ba_\bm_\be  is disabled; otherwise, _\bn_\ba_\bm_\be_\bs are
 536               enabled.  For example, to use the t\bte\bes\bst\bt binary found via the P\bPA\bAT\bTH\bH
 537               instead  of  the  shell builtin version, run ``enable -n test''.
 538               The -\b-f\bf option means to load the new builtin  command  _\bn_\ba_\bm_\be  from
 539               shared object _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be, on systems that support dynamic loading.
 540               The -\b-d\bd option will delete a builtin previously loaded  with  -\b-f\bf.
 541               If no _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied,
 542               a list of shell builtins is printed.  With no other option argu-
 543               ments,  the  list consists of all enabled shell builtins.  If -\b-n\bn
 544               is supplied, only disabled builtins are printed.  If -\b-a\ba is  sup-
 545               plied,  the  list printed includes all builtins, with an indica-
 546               tion of whether or not each is enabled.  If -\b-s\bs is supplied,  the
 547               output  is restricted to the POSIX _\bs_\bp_\be_\bc_\bi_\ba_\bl builtins.  The return
 548               value is 0 unless a _\bn_\ba_\bm_\be is not a shell builtin or there  is  an
 549               error loading a new builtin from a shared object.
 550
 551        e\bev\bva\bal\bl [_\ba_\br_\bg ...]
 552               The  _\ba_\br_\bgs  are read and concatenated together into a single com-
 553               mand.  This command is then read and executed by the shell,  and
 554               its  exit status is returned as the value of e\bev\bva\bal\bl.  If there are
 555               no _\ba_\br_\bg_\bs, or only null arguments, e\bev\bva\bal\bl returns 0.
 556
 557        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]]
 558               If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is specified, it replaces the shell.  No new  process
 559               is  created.  The _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs become the arguments to _\bc_\bo_\bm_\bm_\ba_\bn_\bd.  If
 560               the -\b-l\bl option is supplied, the shell places a dash at the begin-
 561               ning  of  the  zeroth  argument passed to _\bc_\bo_\bm_\bm_\ba_\bn_\bd.  This is what
 562               _\bl_\bo_\bg_\bi_\bn(1) does.  The -\b-c\bc option causes _\bc_\bo_\bm_\bm_\ba_\bn_\bd to be executed with
 563               an  empty environment.  If -\b-a\ba is supplied, the shell passes _\bn_\ba_\bm_\be
 564               as the zeroth argument to the executed command.  If _\bc_\bo_\bm_\bm_\ba_\bn_\bd can-
 565               not  be executed for some reason, a non-interactive shell exits,
 566               unless the e\bex\bxe\bec\bcf\bfa\bai\bil\bl shell option is enabled.  In that  case,  it
 567               returns  failure.   An  interactive shell returns failure if the
 568               file cannot be executed.  A subshell  exits  unconditionally  if
 569               e\bex\bxe\bec\bc  fails.  If _\bc_\bo_\bm_\bm_\ba_\bn_\bd is not specified, any redirections take
 570               effect in the current shell, and the return  status  is  0.   If
 571               there is a redirection error, the return status is 1.
 572
 573        e\bex\bxi\bit\bt [_\bn]
 574               Cause  the  shell  to exit with a status of _\bn.  If _\bn is omitted,
 575               the exit status is that of the last command executed.  A trap on
 576               E\bEX\bXI\bIT\bT is executed before the shell terminates.
 577
 578        e\bex\bxp\bpo\bor\brt\bt [-\b-f\bfn\bn] [_\bn_\ba_\bm_\be[=_\bw_\bo_\br_\bd]] ...
 579        e\bex\bxp\bpo\bor\brt\bt -\b-p\bp
 580               The  supplied _\bn_\ba_\bm_\be_\bs are marked for automatic export to the envi-
 581               ronment of subsequently executed commands.  If the -\b-f\bf option  is
 582               given,  the _\bn_\ba_\bm_\be_\bs refer to functions.  If no _\bn_\ba_\bm_\be_\bs are given, or
 583               if the -\b-p\bp option is supplied, a list of names  of  all  exported
 584               variables  is printed.  The -\b-n\bn option causes the export property
 585               to be removed from each _\bn_\ba_\bm_\be.  If a variable name is followed by
 586               =_\bw_\bo_\br_\bd, the value of the variable is set to _\bw_\bo_\br_\bd.  e\bex\bxp\bpo\bor\brt\bt returns
 587               an exit status of 0 unless an invalid option is encountered, one
 588               of  the  _\bn_\ba_\bm_\be_\bs is not a valid shell variable name, or -\b-f\bf is sup-
 589               plied with a _\bn_\ba_\bm_\be that is not a function.
 590
 591        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]
 592        f\bfc\bc -\b-s\bs [_\bp_\ba_\bt=_\br_\be_\bp] [_\bc_\bm_\bd]
 593               The first form selects a range of commands from  _\bf_\bi_\br_\bs_\bt  to  _\bl_\ba_\bs_\bt
 594               from  the  history  list  and  displays or edits and re-executes
 595               them.  _\bF_\bi_\br_\bs_\bt and _\bl_\ba_\bs_\bt may be specified as a  string  (to  locate
 596               the  last command beginning with that string) or as a number (an
 597               index into the history list, where a negative number is used  as
 598               an  offset  from  the  current  command number).  If _\bl_\ba_\bs_\bt is not
 599               specified, it is set to the current command for listing (so that
 600               ``fc  -l  -10'' prints the last 10 commands) and to _\bf_\bi_\br_\bs_\bt other-
 601               wise.  If _\bf_\bi_\br_\bs_\bt is not specified, it is set to the previous com-
 602               mand for editing and -16 for listing.
 603
 604               The  -\b-n\bn option suppresses the command numbers when listing.  The
 605               -\b-r\br option reverses the order of the commands.  If the -\b-l\bl  option
 606               is  given,  the  commands are listed on standard output.  Other-
 607               wise, the editor given by _\be_\bn_\ba_\bm_\be is invoked on a file  containing
 608               those  commands.  If _\be_\bn_\ba_\bm_\be is not given, the value of the F\bFC\bCE\bED\bDI\bIT\bT
 609               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.
 610               If  neither  variable  is set, _\bv_\bi is used.  When editing is com-
 611               plete, the edited commands are echoed and executed.
 612
 613               In the second form, _\bc_\bo_\bm_\bm_\ba_\bn_\bd is re-executed after  each  instance
 614               of  _\bp_\ba_\bt  is replaced by _\br_\be_\bp.  _\bC_\bo_\bm_\bm_\ba_\bn_\bd is interpreted the same as
 615               _\bf_\bi_\br_\bs_\bt above.  A useful alias to use with this is ``r="fc  -s"'',
 616               so  that  typing  ``r  cc'' runs the last command beginning with
 617               ``cc'' and typing ``r'' re-executes the last command.
 618
 619               If the first form is used, the  return  value  is  0  unless  an
 620               invalid  option  is encountered or _\bf_\bi_\br_\bs_\bt or _\bl_\ba_\bs_\bt specify history
 621               lines out of range.  If the -\b-e\be option is  supplied,  the  return
 622               value is the value of the last command executed or failure if an
 623               error occurs with the temporary file of commands.  If the second
 624               form  is  used, the return status is that of the command re-exe-
 625               cuted, unless _\bc_\bm_\bd does not specify  a  valid  history  line,  in
 626               which case f\bfc\bc returns failure.
 627
 628        f\bfg\bg [_\bj_\bo_\bb_\bs_\bp_\be_\bc]
 629               Resume  _\bj_\bo_\bb_\bs_\bp_\be_\bc  in the foreground, and make it the current job.
 630               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
 631               is  used.   The  return value is that of the command placed into
 632               the foreground, or failure if run when job control  is  disabled
 633               or, when run with job control enabled, if _\bj_\bo_\bb_\bs_\bp_\be_\bc does not spec-
 634               ify a valid job or _\bj_\bo_\bb_\bs_\bp_\be_\bc specifies  a  job  that  was  started
 635               without job control.
 636
 637        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]
 638               g\bge\bet\bto\bop\bpt\bts\bs  is used by shell procedures to parse positional parame-
 639               ters.  _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg contains the option  characters  to  be  recog-
 640               nized;  if  a  character  is  followed by a colon, the option is
 641               expected to have an argument, which should be separated from  it
 642               by  white space.  The colon and question mark characters may not
 643               be used as option characters.  Each time it is invoked,  g\bge\bet\bto\bop\bpt\bts\bs
 644               places  the next option in the shell variable _\bn_\ba_\bm_\be, initializing
 645               _\bn_\ba_\bm_\be if it does not exist, and the index of the next argument to
 646               be processed into the variable O\bOP\bPT\bTI\bIN\bND\bD.  O\bOP\bPT\bTI\bIN\bND\bD is initialized to
 647               1 each time the shell or a shell script  is  invoked.   When  an
 648               option  requires  an argument, g\bge\bet\bto\bop\bpt\bts\bs places that argument into
 649               the variable O\bOP\bPT\bTA\bAR\bRG\bG.  The shell does not reset O\bOP\bPT\bTI\bIN\bND\bD  automati-
 650               cally;  it  must  be  manually  reset  between multiple calls to
 651               g\bge\bet\bto\bop\bpt\bts\bs within the same shell invocation if a new set of parame-
 652               ters is to be used.
 653
 654               When  the  end  of  options is encountered, g\bge\bet\bto\bop\bpt\bts\bs exits with a
 655               return value greater than zero.  O\bOP\bPT\bTI\bIN\bND\bD is set to the  index  of
 656               the first non-option argument, and _\bn_\ba_\bm_\be is set to ?.
 657
 658               g\bge\bet\bto\bop\bpt\bts\bs  normally  parses the positional parameters, but if more
 659               arguments are given in _\ba_\br_\bg_\bs, g\bge\bet\bto\bop\bpt\bts\bs parses those instead.
 660
 661               g\bge\bet\bto\bop\bpt\bts\bs can report errors in two ways.  If the  first  character
 662               of  _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg  is  a  colon, _\bs_\bi_\bl_\be_\bn_\bt error reporting is used.  In
 663               normal operation, diagnostic messages are printed  when  invalid
 664               options  or  missing  option  arguments are encountered.  If the
 665               variable O\bOP\bPT\bTE\bER\bRR\bR is set to 0, no  error  messages  will  be  dis-
 666               played, even if the first character of _\bo_\bp_\bt_\bs_\bt_\br_\bi_\bn_\bg is not a colon.
 667
 668               If an invalid option is seen, g\bge\bet\bto\bop\bpt\bts\bs places ? into _\bn_\ba_\bm_\be and, if
 669               not silent, prints an  error  message  and  unsets  O\bOP\bPT\bTA\bAR\bRG\bG.   If
 670               g\bge\bet\bto\bop\bpt\bts\bs  is  silent,  the  option  character  found is placed in
 671               O\bOP\bPT\bTA\bAR\bRG\bG and no diagnostic message is printed.
 672
 673               If a required argument is not found, and g\bge\bet\bto\bop\bpt\bts\bs is not  silent,
 674               a  question  mark  (?\b?) is placed in _\bn_\ba_\bm_\be, O\bOP\bPT\bTA\bAR\bRG\bG is unset, and a
 675               diagnostic message is printed.  If g\bge\bet\bto\bop\bpt\bts\bs  is  silent,  then  a
 676               colon  (:\b:)  is  placed  in  _\bn_\ba_\bm_\be and O\bOP\bPT\bTA\bAR\bRG\bG is set to the option
 677               character found.
 678
 679               g\bge\bet\bto\bop\bpt\bts\bs returns true if an option, specified or unspecified,  is
 680               found.  It returns false if the end of options is encountered or
 681               an error occurs.
 682
 683        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]
 684               Each time h\bha\bas\bsh\bh is invoked, the full pathname of the command _\bn_\ba_\bm_\be
 685               is  determined  by searching the directories in $\b$P\bPA\bAT\bTH\bH and remem-
 686               bered.  Any previously-remembered pathname is discarded.  If the
 687               -\b-p\bp option is supplied, no path search is performed, and _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be
 688               is used as the full filename of  the  command.   The  -\b-r\br  option
 689               causes  the  shell  to  forget all remembered locations.  The -\b-d\bd
 690               option causes the shell to forget  the  remembered  location  of
 691               each  _\bn_\ba_\bm_\be.   If the -\b-t\bt option is supplied, the full pathname to
 692               which each _\bn_\ba_\bm_\be corresponds is printed.  If multiple _\bn_\ba_\bm_\be  argu-
 693               ments  are  supplied  with  -\b-t\bt,  the  _\bn_\ba_\bm_\be is printed before the
 694               hashed full pathname.  The -\b-l\bl option causes output  to  be  dis-
 695               played in a format that may be reused as input.  If no arguments
 696               are given, or if only -\b-l\bl is supplied, information  about  remem-
 697               bered  commands  is printed.  The return status is true unless a
 698               _\bn_\ba_\bm_\be is not found or an invalid option is supplied.
 699
 700        h\bhe\bel\blp\bp [-\b-d\bdm\bms\bs] [_\bp_\ba_\bt_\bt_\be_\br_\bn]
 701               Display helpful information about builtin commands.  If  _\bp_\ba_\bt_\bt_\be_\br_\bn
 702               is  specified, h\bhe\bel\blp\bp gives detailed help on all commands matching
 703               _\bp_\ba_\bt_\bt_\be_\br_\bn; otherwise help for all the builtins and  shell  control
 704               structures is printed.
 705               -\b-d\bd     Display a short description of each _\bp_\ba_\bt_\bt_\be_\br_\bn
 706               -\b-m\bm     Display the description of each _\bp_\ba_\bt_\bt_\be_\br_\bn in a manpage-like
 707                      format
 708               -\b-s\bs     Display only a short usage synopsis for each _\bp_\ba_\bt_\bt_\be_\br_\bn
 709
 710               The return status is 0 unless no command matches _\bp_\ba_\bt_\bt_\be_\br_\bn.
 711
 712        h\bhi\bis\bst\bto\bor\bry\by [\b[_\bn]\b]
 713        h\bhi\bis\bst\bto\bor\bry\by -\b-c\bc
 714        h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
 715        h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd _\bs_\bt_\ba_\br_\bt-_\be_\bn_\bd
 716        h\bhi\bis\bst\bto\bor\bry\by -\b-a\ban\bnr\brw\bw [_\bf_\bi_\bl_\be_\bn_\ba_\bm_\be]
 717        h\bhi\bis\bst\bto\bor\bry\by -\b-p\bp _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
 718        h\bhi\bis\bst\bto\bor\bry\by -\b-s\bs _\ba_\br_\bg [_\ba_\br_\bg _\b._\b._\b.]
 719               With no options, display the command history list with line num-
 720               bers.  Lines listed with a *\b* have been modified.  An argument of
 721               _\bn lists only the last _\bn lines.  If the shell variable  H\bHI\bIS\bST\bTT\bTI\bIM\bME\bE-\b-
 722               F\bFO\bOR\bRM\bMA\bAT\bT  is  set  and not null, it is used as a format string for
 723               _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3) to display the time stamp associated with each  dis-
 724               played  history  entry.  No intervening blank is printed between
 725               the formatted time stamp and the history line.  If  _\bf_\bi_\bl_\be_\bn_\ba_\bm_\be  is
 726               supplied,  it  is  used as the name of the history file; if not,
 727               the value of H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE is used.  Options, if supplied,  have  the
 728               following meanings:
 729               -\b-c\bc     Clear the history list by deleting all the entries.
 730               -\b-d\bd _\bo_\bf_\bf_\bs_\be_\bt
 731                      Delete  the  history entry at position _\bo_\bf_\bf_\bs_\be_\bt.  If _\bo_\bf_\bf_\bs_\be_\bt
 732                      is negative, it is interpreted as relative to one greater
 733                      than the last history position, so negative indices count
 734                      back from the end of the history,  and  an  index  of  -1
 735                      refers to the current h\bhi\bis\bst\bto\bor\bry\by -\b-d\bd command.
 736               -\b-d\bd _\bs_\bt_\ba_\br_\bt-_\be_\bn_\bd
 737                      Delete  the  history  entries between positions _\bs_\bt_\ba_\br_\bt and
 738                      _\be_\bn_\bd, inclusive.  Positive and negative values  for  _\bs_\bt_\ba_\br_\bt
 739                      and _\be_\bn_\bd are interpreted as described above.
 740               -\b-a\ba     Append  the  ``new''  history  lines to the history file.
 741                      These are history lines entered since  the  beginning  of
 742                      the current b\bba\bas\bsh\bh session, but not already appended to the
 743                      history file.
 744               -\b-n\bn     Read the history lines not already read from the  history
 745                      file  into  the  current  history  list.  These are lines
 746                      appended to the history file since the beginning  of  the
 747                      current b\bba\bas\bsh\bh session.
 748               -\b-r\br     Read  the contents of the history file and append them to
 749                      the current history list.
 750               -\b-w\bw     Write the current history list to the history file, over-
 751                      writing the history file's contents.
 752               -\b-p\bp     Perform  history  substitution  on the following _\ba_\br_\bg_\bs and
 753                      display the result on  the  standard  output.   Does  not
 754                      store  the results in the history list.  Each _\ba_\br_\bg must be
 755                      quoted to disable normal history expansion.
 756               -\b-s\bs     Store the _\ba_\br_\bg_\bs in the history list  as  a  single  entry.
 757                      The  last  command  in the history list is removed before
 758                      the _\ba_\br_\bg_\bs are added.
 759
 760               If the H\bHI\bIS\bST\bTT\bTI\bIM\bME\bEF\bFO\bOR\bRM\bMA\bAT\bT variable is set, the time  stamp  informa-
 761               tion  associated  with each history entry is written to the his-
 762               tory file, marked with the history comment character.  When  the
 763               history  file  is read, lines beginning with the history comment
 764               character followed immediately by a  digit  are  interpreted  as
 765               timestamps for the following history entry.  The return value is
 766               0 unless an invalid option is encountered, an error occurs while
 767               reading  or  writing the history file, an invalid _\bo_\bf_\bf_\bs_\be_\bt is sup-
 768               plied as an argument to -\b-d\bd, or the history expansion supplied as
 769               an argument to -\b-p\bp fails.
 770
 771        j\bjo\bob\bbs\bs [-\b-l\bln\bnp\bpr\brs\bs] [ _\bj_\bo_\bb_\bs_\bp_\be_\bc ... ]
 772        j\bjo\bob\bbs\bs -\b-x\bx _\bc_\bo_\bm_\bm_\ba_\bn_\bd [ _\ba_\br_\bg_\bs ... ]
 773               The first form lists the active jobs.  The options have the fol-
 774               lowing meanings:
 775               -\b-l\bl     List process IDs in addition to the normal information.
 776               -\b-n\bn     Display information only about  jobs  that  have  changed
 777                      status since the user was last notified of their status.
 778               -\b-p\bp     List  only  the  process  ID  of  the job's process group
 779                      leader.
 780               -\b-r\br     Display only running jobs.
 781               -\b-s\bs     Display only stopped jobs.
 782
 783               If _\bj_\bo_\bb_\bs_\bp_\be_\bc is given, output is restricted to  information  about
 784               that  job.   The  return status is 0 unless an invalid option is
 785               encountered or an invalid _\bj_\bo_\bb_\bs_\bp_\be_\bc is supplied.
 786
 787               If the -\b-x\bx option is supplied, j\bjo\bob\bbs\bs replaces any _\bj_\bo_\bb_\bs_\bp_\be_\bc found in
 788               _\bc_\bo_\bm_\bm_\ba_\bn_\bd  or  _\ba_\br_\bg_\bs  with  the corresponding process group ID, and
 789               executes _\bc_\bo_\bm_\bm_\ba_\bn_\bd passing it _\ba_\br_\bg_\bs, returning its exit status.
 790
 791        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] ...
 792        k\bki\bil\bll\bl -\b-l\bl|-\b-L\bL [_\bs_\bi_\bg_\bs_\bp_\be_\bc | _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs]
 793               Send the signal named by _\bs_\bi_\bg_\bs_\bp_\be_\bc  or  _\bs_\bi_\bg_\bn_\bu_\bm  to  the  processes
 794               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
 795               signal name such as S\bSI\bIG\bGK\bKI\bIL\bLL\bL (with or without the S\bSI\bIG\bG prefix)  or
 796               a  signal  number; _\bs_\bi_\bg_\bn_\bu_\bm is a signal number.  If _\bs_\bi_\bg_\bs_\bp_\be_\bc is not
 797               present, then S\bSI\bIG\bGT\bTE\bER\bRM\bM is assumed.  An argument of -\b-l\bl  lists  the
 798               signal  names.   If any arguments are supplied when -\b-l\bl is given,
 799               the names of the signals  corresponding  to  the  arguments  are
 800               listed, and the return status is 0.  The _\be_\bx_\bi_\bt_\b__\bs_\bt_\ba_\bt_\bu_\bs argument to
 801               -\b-l\bl is a number specifying either a signal  number  or  the  exit
 802               status  of  a  process terminated by a signal.  The -\b-L\bL option is
 803               equivalent to -\b-l\bl.  k\bki\bil\bll\bl returns true if at least one signal  was
 804               successfully  sent,  or  false  if an error occurs or an invalid
 805               option is encountered.
 806
 807        l\ble\bet\bt _\ba_\br_\bg [_\ba_\br_\bg ...]
 808               Each _\ba_\br_\bg is an arithmetic expression to be evaluated (see A\bAR\bRI\bIT\bTH\bH-\b-
 809               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
 810               returns 1; 0 is returned otherwise.
 811
 812        l\blo\boc\bca\bal\bl [_\bo_\bp_\bt_\bi_\bo_\bn] [_\bn_\ba_\bm_\be[=_\bv_\ba_\bl_\bu_\be] ... | - ]
 813               For each argument, a local variable named _\bn_\ba_\bm_\be is  created,  and
 814               assigned  _\bv_\ba_\bl_\bu_\be.   The _\bo_\bp_\bt_\bi_\bo_\bn can be any of the options accepted
 815               by d\bde\bec\bcl\bla\bar\bre\be.  When l\blo\boc\bca\bal\bl is used within a function, it causes the
 816               variable  _\bn_\ba_\bm_\be  to have a visible scope restricted to that func-
 817               tion and its children.  If _\bn_\ba_\bm_\be is -, the set of  shell  options
 818               is  made  local to the function in which l\blo\boc\bca\bal\bl is invoked: shell
 819               options changed using the s\bse\bet\bt builtin inside  the  function  are
 820               restored  to  their  original  values when the function returns.
 821               With no operands, l\blo\boc\bca\bal\bl writes a list of local variables to  the
 822               standard  output.  It is an error to use l\blo\boc\bca\bal\bl when not within a
 823               function.  The return status is 0 unless l\blo\boc\bca\bal\bl is used outside a
 824               function,  an  invalid  _\bn_\ba_\bm_\be  is supplied, or _\bn_\ba_\bm_\be is a readonly
 825               variable.
 826
 827        l\blo\bog\bgo\bou\but\bt Exit a login shell.
 828
 829        m\bma\bap\bpf\bfi\bil\ble\be [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\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
 830        _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk] [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
 831        r\bre\bea\bad\bda\bar\brr\bra\bay\by [-\b-d\bd _\bd_\be_\bl_\bi_\bm] [-\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
 832        _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk] [-\b-c\bc _\bq_\bu_\ba_\bn_\bt_\bu_\bm] [_\ba_\br_\br_\ba_\by]
 833               Read lines from the standard input into the indexed array  vari-
 834               able  _\ba_\br_\br_\ba_\by, or from file descriptor _\bf_\bd if the -\b-u\bu option is sup-
 835               plied.  The variable M\bMA\bAP\bPF\bFI\bIL\bLE\bE is the default _\ba_\br_\br_\ba_\by.  Options,  if
 836               supplied, have the following meanings:
 837               -\b-d\bd     The  first  character  of _\bd_\be_\bl_\bi_\bm is used to terminate each
 838                      input line, rather than newline.  If _\bd_\be_\bl_\bi_\bm is  the  empty
 839                      string, m\bma\bap\bpf\bfi\bil\ble\be will terminate a line when it reads a NUL
 840                      character.
 841               -\b-n\bn     Copy at most _\bc_\bo_\bu_\bn_\bt lines.  If _\bc_\bo_\bu_\bn_\bt is 0, all  lines  are
 842                      copied.
 843               -\b-O\bO     Begin  assigning  to  _\ba_\br_\br_\ba_\by at index _\bo_\br_\bi_\bg_\bi_\bn.  The default
 844                      index is 0.
 845               -\b-s\bs     Discard the first _\bc_\bo_\bu_\bn_\bt lines read.
 846               -\b-t\bt     Remove a trailing _\bd_\be_\bl_\bi_\bm (default newline) from each  line
 847                      read.
 848               -\b-u\bu     Read  lines  from file descriptor _\bf_\bd instead of the stan-
 849                      dard input.
 850               -\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
 851                      -\b-c\bc option specifies _\bq_\bu_\ba_\bn_\bt_\bu_\bm.
 852               -\b-c\bc     Specify  the  number  of  lines read between each call to
 853                      _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk.
 854
 855               If -\b-C\bC is specified without -\b-c\bc,  the  default  quantum  is  5000.
 856               When _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk is evaluated, it is supplied the index of the next
 857               array element to be assigned and the line to be assigned to that
 858               element  as  additional  arguments.  _\bc_\ba_\bl_\bl_\bb_\ba_\bc_\bk is evaluated after
 859               the line is read but before the array element is assigned.
 860
 861               If not supplied with an  explicit  origin,  m\bma\bap\bpf\bfi\bil\ble\be  will  clear
 862               _\ba_\br_\br_\ba_\by before assigning to it.
 863
 864               m\bma\bap\bpf\bfi\bil\ble\be  returns successfully unless an invalid option or option
 865               argument is supplied, _\ba_\br_\br_\ba_\by is invalid or  unassignable,  or  if
 866               _\ba_\br_\br_\ba_\by is not an indexed array.
 867
 868        p\bpo\bop\bpd\bd [-n\bn] [+_\bn] [-_\bn]
 869               Removes  entries  from  the directory stack.  With no arguments,
 870               removes the top directory from the stack, and performs a  c\bcd\bd  to
 871               the new top directory.  Arguments, if supplied, have the follow-
 872               ing meanings:
 873               -\b-n\bn     Suppresses the normal change of directory  when  removing
 874                      directories  from  the  stack,  so that only the stack is
 875                      manipulated.
 876               +\b+_\bn     Removes the _\bnth entry counting from the left of the  list
 877                      shown  by  d\bdi\bir\brs\bs, starting with zero.  For example: ``popd
 878                      +0'' removes the first directory, ``popd +1'' the second.
 879               -\b-_\bn     Removes the _\bnth entry counting from the right of the list
 880                      shown  by  d\bdi\bir\brs\bs, starting with zero.  For example: ``popd
 881                      -0'' removes the last directory, ``popd -1'' the next  to
 882                      last.
 883
 884               If  the p\bpo\bop\bpd\bd command is successful, a d\bdi\bir\brs\bs is performed as well,
 885               and the return status is 0.  p\bpo\bop\bpd\bd returns false  if  an  invalid
 886               option is encountered, the directory stack is empty, a non-exis-
 887               tent directory stack entry is specified, or the directory change
 888               fails.
 889
 890        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]
 891               Write  the  formatted _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt_\bs to the standard output under the
 892               control of the _\bf_\bo_\br_\bm_\ba_\bt.  The -\b-v\bv option causes the  output  to  be
 893               assigned  to  the  variable _\bv_\ba_\br rather than being printed to the
 894               standard output.
 895
 896               The _\bf_\bo_\br_\bm_\ba_\bt is a character string which contains three  types  of
 897               objects:  plain  characters, which are simply copied to standard
 898               output, character escape  sequences,  which  are  converted  and
 899               copied  to  the standard output, and format specifications, each
 900               of which causes printing of the next  successive  _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt.   In
 901               addition to the standard _\bp_\br_\bi_\bn_\bt_\bf(1) format specifications, p\bpr\bri\bin\bnt\btf\bf
 902               interprets the following extensions:
 903               %\b%b\bb     causes p\bpr\bri\bin\bnt\btf\bf to expand backslash escape sequences in the
 904                      corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt in the same way as e\bec\bch\bho\bo -\b-e\be.
 905               %\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
 906                      format that can be reused as shell input.
 907               %\b%(\b(_\bd_\ba_\bt_\be_\bf_\bm_\bt)\b)T\bT
 908                      causes p\bpr\bri\bin\bnt\btf\bf to output the  date-time  string  resulting
 909                      from  using  _\bd_\ba_\bt_\be_\bf_\bm_\bt  as a format string for _\bs_\bt_\br_\bf_\bt_\bi_\bm_\be(3).
 910                      The corresponding _\ba_\br_\bg_\bu_\bm_\be_\bn_\bt is an integer representing the
 911                      number  of seconds since the epoch.  Two special argument
 912                      values may be used: -1 represents the current  time,  and
 913                      -2  represents  the  time  the  shell was invoked.  If no
 914                      argument is specified, conversion behaves as  if  -1  had
 915                      been  given.   This  is  an exception to the usual p\bpr\bri\bin\bnt\btf\bf
 916                      behavior.
 917
 918               Arguments to non-string format specifiers are treated as C  con-
 919               stants, except that a leading plus or minus sign is allowed, and
 920               if the leading character is a single or double quote, the  value
 921               is the ASCII value of the following character.
 922
 923               The  _\bf_\bo_\br_\bm_\ba_\bt  is  reused as necessary to consume all of the _\ba_\br_\bg_\bu_\b-
 924               _\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,
 925               the  extra  format  specifications  behave as if a zero value or
 926               null string, as appropriate,  had  been  supplied.   The  return
 927               value is zero on success, non-zero on failure.
 928
 929        p\bpu\bus\bsh\bhd\bd [-\b-n\bn] [+_\bn] [-_\bn]
 930        p\bpu\bus\bsh\bhd\bd [-\b-n\bn] [_\bd_\bi_\br]
 931               Adds  a  directory to the top of the directory stack, or rotates
 932               the stack, making the new top of the stack the  current  working
 933               directory.   With  no  arguments,  p\bpu\bus\bsh\bhd\bd  exchanges  the top two
 934               directories and returns 0, unless the directory stack is  empty.
 935               Arguments, if supplied, have the following meanings:
 936               -\b-n\bn     Suppresses  the  normal change of directory when rotating
 937                      or adding directories to the  stack,  so  that  only  the
 938                      stack is manipulated.
 939               +\b+_\bn     Rotates  the  stack  so  that the _\bnth directory (counting
 940                      from the left of the list shown by  d\bdi\bir\brs\bs,  starting  with
 941                      zero) is at the top.
 942               -\b-_\bn     Rotates  the  stack  so  that the _\bnth directory (counting
 943                      from the right of the list shown by d\bdi\bir\brs\bs,  starting  with
 944                      zero) is at the top.
 945               _\bd_\bi_\br    Adds _\bd_\bi_\br to the directory stack at the top, making it the
 946                      new current working directory as if it had been  supplied
 947                      as the argument to the c\bcd\bd builtin.
 948
 949               If the p\bpu\bus\bsh\bhd\bd command is successful, a d\bdi\bir\brs\bs is performed as well.
 950               If the first form is used, p\bpu\bus\bsh\bhd\bd returns 0 unless the cd to  _\bd_\bi_\br
 951               fails.   With the second form, p\bpu\bus\bsh\bhd\bd returns 0 unless the direc-
 952               tory stack is empty, a non-existent directory stack  element  is
 953               specified,  or the directory change to the specified new current
 954               directory fails.
 955
 956        p\bpw\bwd\bd [-\b-L\bLP\bP]
 957               Print the absolute pathname of the  current  working  directory.
 958               The pathname printed contains no symbolic links if the -\b-P\bP option
 959               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
 960               is  enabled.  If the -\b-L\bL option is used, the pathname printed may
 961               contain symbolic links.  The return status is 0 unless an  error
 962               occurs  while  reading  the  name of the current directory or an
 963               invalid option is supplied.
 964
 965        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
 966        _\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 ...]
 967               One  line  is  read  from  the  standard input, or from the file
 968               descriptor _\bf_\bd supplied as an argument to the  -\b-u\bu  option,  split
 969               into  words  as  described  above  under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg, and the
 970               first word is assigned to the first _\bn_\ba_\bm_\be, the second word to the
 971               second _\bn_\ba_\bm_\be, and so on.  If there are more words than names, the
 972               remaining words and their intervening delimiters are assigned to
 973               the  last  _\bn_\ba_\bm_\be.   If  there are fewer words read from the input
 974               stream than names, the remaining names are assigned  empty  val-
 975               ues.   The  characters  in  I\bIF\bFS\bS  are used to split the line into
 976               words  using  the  same  rules  the  shell  uses  for  expansion
 977               (described above under W\bWo\bor\brd\bd S\bSp\bpl\bli\bit\btt\bti\bin\bng\bg).  The backslash character
 978               (\\b\) may be used to remove any special meaning for the next char-
 979               acter  read  and  for  line continuation.  Options, if supplied,
 980               have the following meanings:
 981               -\b-a\ba _\ba_\bn_\ba_\bm_\be
 982                      The words are assigned to sequential indices of the array
 983                      variable _\ba_\bn_\ba_\bm_\be, starting at 0.  _\ba_\bn_\ba_\bm_\be is unset before any
 984                      new  values  are  assigned.   Other  _\bn_\ba_\bm_\be  arguments  are
 985                      ignored.
 986               -\b-d\bd _\bd_\be_\bl_\bi_\bm
 987                      The  first  character  of  _\bd_\be_\bl_\bi_\bm is used to terminate the
 988                      input line, rather than newline.  If _\bd_\be_\bl_\bi_\bm is  the  empty
 989                      string,  r\bre\bea\bad\bd  will  terminate a line when it reads a NUL
 990                      character.
 991               -\b-e\be     If the standard input is coming from a terminal, r\bre\bea\bad\bdl\bli\bin\bne\be
 992                      (see  R\bRE\bEA\bAD\bDL\bLI\bIN\bNE\bE  above) is used to obtain the line.  Read-
 993                      line uses the current (or default, if  line  editing  was
 994                      not  previously  active) editing settings, but uses Read-
 995                      line's default filename completion.
 996               -\b-i\bi _\bt_\be_\bx_\bt
 997                      If r\bre\bea\bad\bdl\bli\bin\bne\be is being used  to  read  the  line,  _\bt_\be_\bx_\bt  is
 998                      placed into the editing buffer before editing begins.
 999               -\b-n\bn _\bn_\bc_\bh_\ba_\br_\bs
1000                      r\bre\bea\bad\bd  returns after reading _\bn_\bc_\bh_\ba_\br_\bs characters rather than
1001                      waiting for a complete line of input, but honors a delim-
1002                      iter  if fewer than _\bn_\bc_\bh_\ba_\br_\bs characters are read before the
1003                      delimiter.
1004               -\b-N\bN _\bn_\bc_\bh_\ba_\br_\bs
1005                      r\bre\bea\bad\bd returns  after  reading  exactly  _\bn_\bc_\bh_\ba_\br_\bs  characters
1006                      rather  than waiting for a complete line of input, unless
1007                      EOF is encountered or r\bre\bea\bad\bd times out.  Delimiter  charac-
1008                      ters  encountered  in the input are not treated specially
1009                      and do not cause r\bre\bea\bad\bd to return until  _\bn_\bc_\bh_\ba_\br_\bs  characters
1010                      are  read.   The result is not split on the characters in
1011                      I\bIF\bFS\bS; the intent is that the variable is assigned  exactly
1012                      the characters read (with the exception of backslash; see
1013                      the -\b-r\br option below).
1014               -\b-p\bp _\bp_\br_\bo_\bm_\bp_\bt
1015                      Display _\bp_\br_\bo_\bm_\bp_\bt on standard error, without a trailing new-
1016                      line, before attempting to read any input.  The prompt is
1017                      displayed only if input is coming from a terminal.
1018               -\b-r\br     Backslash does not act as an escape character.  The back-
1019                      slash  is considered to be part of the line.  In particu-
1020                      lar, a backslash-newline pair may not then be used  as  a
1021                      line continuation.
1022               -\b-s\bs     Silent mode.  If input is coming from a terminal, charac-
1023                      ters are not echoed.
1024               -\b-t\bt _\bt_\bi_\bm_\be_\bo_\bu_\bt
1025                      Cause r\bre\bea\bad\bd to time out and return failure if  a  complete
1026                      line  of  input  (or a specified number of characters) is
1027                      not read within _\bt_\bi_\bm_\be_\bo_\bu_\bt seconds.  _\bt_\bi_\bm_\be_\bo_\bu_\bt may be a  deci-
1028                      mal  number with a fractional portion following the deci-
1029                      mal point.  This option is  only  effective  if  r\bre\bea\bad\bd  is
1030                      reading  input  from  a  terminal, pipe, or other special
1031                      file; it has no effect when reading from  regular  files.
1032                      If r\bre\bea\bad\bd times out, r\bre\bea\bad\bd saves any partial input read into
1033                      the specified variable  _\bn_\ba_\bm_\be.   If  _\bt_\bi_\bm_\be_\bo_\bu_\bt  is  0,  r\bre\bea\bad\bd
1034                      returns  immediately,  without  trying  to read any data.
1035                      The exit status is 0 if input is available on the  speci-
1036                      fied  file descriptor, non-zero otherwise.  The exit sta-
1037                      tus is greater than 128 if the timeout is exceeded.
1038               -\b-u\bu _\bf_\bd  Read input from file descriptor _\bf_\bd.
1039
1040               If no _\bn_\ba_\bm_\be_\bs are supplied, the line read is assigned to the vari-
1041               able  R\bRE\bEP\bPL\bLY\bY.   The  exit  status  is zero, unless end-of-file is
1042               encountered, r\bre\bea\bad\bd times out (in which case the status is greater
1043               than  128),  a variable assignment error (such as assigning to a
1044               readonly variable) occurs, or an invalid file descriptor is sup-
1045               plied as the argument to -\b-u\bu.
1046
1047        r\bre\bea\bad\bdo\bon\bnl\bly\by [-\b-a\baA\bAf\bf] [-\b-p\bp] [_\bn_\ba_\bm_\be[=_\bw_\bo_\br_\bd] ...]
1048               The  given  _\bn_\ba_\bm_\be_\bs are marked readonly; the values of these _\bn_\ba_\bm_\be_\bs
1049               may not be changed by subsequent assignment.  If the  -\b-f\bf  option
1050               is  supplied,  the  functions  corresponding to the _\bn_\ba_\bm_\be_\bs are so
1051               marked.  The  -\b-a\ba  option  restricts  the  variables  to  indexed
1052               arrays;  the  -\b-A\bA  option  restricts the variables to associative
1053               arrays.  If both options are supplied, -\b-A\bA takes precedence.   If
1054               no  _\bn_\ba_\bm_\be arguments are given, or if the -\b-p\bp option is supplied, a
1055               list of all readonly names is printed.  The other options may be
1056               used  to  restrict the output to a subset of the set of readonly
1057               names.  The -\b-p\bp option causes output to be displayed in a  format
1058               that  may be reused as input.  If a variable name is followed by
1059               =_\bw_\bo_\br_\bd, the value of the variable is set  to  _\bw_\bo_\br_\bd.   The  return
1060               status  is 0 unless an invalid option is encountered, one of the
1061               _\bn_\ba_\bm_\be_\bs is not a valid shell variable name, or -\b-f\bf is supplied with
1062               a _\bn_\ba_\bm_\be that is not a function.
1063
1064        r\bre\bet\btu\bur\brn\bn [_\bn]
1065               Causes  a function to stop executing and return the value speci-
1066               fied by _\bn to its caller.  If _\bn is omitted, the return status  is
1067               that  of  the  last  command  executed in the function body.  If
1068               r\bre\bet\btu\bur\brn\bn is executed by a trap handler, the last command  used  to
1069               determine  the  status  is  the last command executed before the
1070               trap handler.  If r\bre\bet\btu\bur\brn\bn is executed during a  D\bDE\bEB\bBU\bUG\bG  trap,  the
1071               last  command  used  to determine the status is the last command
1072               executed by the trap handler  before  r\bre\bet\btu\bur\brn\bn  was  invoked.   If
1073               r\bre\bet\btu\bur\brn\bn  is  used  outside  a function, but during execution of a
1074               script by the .\b.  (s\bso\bou\bur\brc\bce\be) command, it causes the shell  to  stop
1075               executing  that script and return either _\bn or the exit status of
1076               the last command executed within the script as the  exit  status
1077               of  the script.  If _\bn is supplied, the return value is its least
1078               significant 8 bits.  The return status is non-zero if r\bre\bet\btu\bur\brn\bn  is
1079               supplied  a  non-numeric argument, or is used outside a function
1080               and not during execution of a script by .\b. or s\bso\bou\bur\brc\bce\be.   Any  com-
1081               mand  associated  with the R\bRE\bET\bTU\bUR\bRN\bN trap is executed before execu-
1082               tion resumes after the function or script.
1083
1084        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 ...]
1085        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 ...]
1086               Without options, the name and value of each shell  variable  are
1087               displayed in a format that can be reused as input for setting or
1088               resetting the currently-set variables.  Read-only variables can-
1089               not  be  reset.  In _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, only shell variables are listed.
1090               The output is sorted according  to  the  current  locale.   When
1091               options  are specified, they set or unset shell attributes.  Any
1092               arguments remaining after option processing are treated as  val-
1093               ues for the positional parameters and are assigned, in order, to
1094               $\b$1\b1, $\b$2\b2, .\b..\b..\b.  $\b$_\bn.  Options,  if  specified,  have  the  following
1095               meanings:
1096               -\b-a\ba      Each variable or function that is created or modified is
1097                       given the export attribute and marked for export to  the
1098                       environment of subsequent commands.
1099               -\b-b\bb      Report  the status of terminated background jobs immedi-
1100                       ately, rather than before the next primary prompt.  This
1101                       is effective only when job control is enabled.
1102               -\b-e\be      Exit  immediately  if a _\bp_\bi_\bp_\be_\bl_\bi_\bn_\be (which may consist of a
1103                       single _\bs_\bi_\bm_\bp_\bl_\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd), a _\bl_\bi_\bs_\bt, or  a  _\bc_\bo_\bm_\bp_\bo_\bu_\bn_\bd  _\bc_\bo_\bm_\bm_\ba_\bn_\bd
1104                       (see S\bSH\bHE\bEL\bLL\bL G\bGR\bRA\bAM\bMM\bMA\bAR\bR above), exits with a non-zero status.
1105                       The shell does not exit if the  command  that  fails  is
1106                       part  of  the command list immediately following a w\bwh\bhi\bil\ble\be
1107                       or u\bun\bnt\bti\bil\bl keyword, part of the test following the  i\bif\bf  or
1108                       e\bel\bli\bif\bf  reserved  words, part of any command executed in a
1109                       &\b&&\b& or |\b||\b| list except the command following the final  &\b&&\b&
1110                       or |\b||\b|, any command in a pipeline but the last, or if the
1111                       command's return value is being inverted with !\b!.   If  a
1112                       compound  command  other  than a subshell returns a non-
1113                       zero status because a command failed while -\b-e\be was  being
1114                       ignored,  the  shell  does  not exit.  A trap on E\bER\bRR\bR, if
1115                       set, is executed before the shell  exits.   This  option
1116                       applies to the shell environment and each subshell envi-
1117                       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
1118                       above), and may cause subshells to exit before executing
1119                       all the commands in the subshell.
1120
1121                       If a compound command or shell function  executes  in  a
1122                       context  where -\b-e\be is being ignored, none of the commands
1123                       executed within the compound command  or  function  body
1124                       will  be  affected  by the -\b-e\be setting, even if -\b-e\be is set
1125                       and a command returns a failure status.  If  a  compound
1126                       command  or  shell function sets -\b-e\be while executing in a
1127                       context where -\b-e\be is ignored, that setting will not  have
1128                       any  effect  until  the  compound command or the command
1129                       containing the function call completes.
1130               -\b-f\bf      Disable pathname expansion.
1131               -\b-h\bh      Remember the location of commands as they are looked  up
1132                       for execution.  This is enabled by default.
1133               -\b-k\bk      All  arguments  in the form of assignment statements are
1134                       placed in the environment for a command, not just  those
1135                       that precede the command name.
1136               -\b-m\bm      Monitor  mode.   Job control is enabled.  This option is
1137                       on by default for interactive  shells  on  systems  that
1138                       support  it  (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL above).  All processes run
1139                       in a separate process group.  When a background job com-
1140                       pletes, the shell prints a line containing its exit sta-
1141                       tus.
1142               -\b-n\bn      Read commands but do not execute them.  This may be used
1143                       to  check  a  shell  script  for syntax errors.  This is
1144                       ignored by interactive shells.
1145               -\b-o\bo _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be
1146                       The _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be can be one of the following:
1147                       a\bal\bll\ble\bex\bxp\bpo\bor\brt\bt
1148                               Same as -\b-a\ba.
1149                       b\bbr\bra\bac\bce\bee\bex\bxp\bpa\ban\bnd\bd
1150                               Same as -\b-B\bB.
1151                       e\bem\bma\bac\bcs\bs   Use an emacs-style command line  editing  inter-
1152                               face.  This is enabled by default when the shell
1153                               is interactive, unless the shell is started with
1154                               the  -\b--\b-n\bno\boe\bed\bdi\bit\bti\bin\bng\bg  option.  This also affects the
1155                               editing interface used for r\bre\bea\bad\bd -\b-e\be.
1156                       e\ber\brr\bre\bex\bxi\bit\bt Same as -\b-e\be.
1157                       e\ber\brr\brt\btr\bra\bac\bce\be
1158                               Same as -\b-E\bE.
1159                       f\bfu\bun\bnc\bct\btr\bra\bac\bce\be
1160                               Same as -\b-T\bT.
1161                       h\bha\bas\bsh\bha\bal\bll\bl Same as -\b-h\bh.
1162                       h\bhi\bis\bst\bte\bex\bxp\bpa\ban\bnd\bd
1163                               Same as -\b-H\bH.
1164                       h\bhi\bis\bst\bto\bor\bry\by Enable command history, as described above under
1165                               H\bHI\bIS\bST\bTO\bOR\bRY\bY.  This option is on by default in inter-
1166                               active shells.
1167                       i\big\bgn\bno\bor\bre\bee\beo\bof\bf
1168                               The  effect  is  as   if   the   shell   command
1169                               ``IGNOREEOF=10''  had  been  executed (see S\bSh\bhe\bel\bll\bl
1170                               V\bVa\bar\bri\bia\bab\bbl\ble\bes\bs above).
1171                       k\bke\bey\byw\bwo\bor\brd\bd Same as -\b-k\bk.
1172                       m\bmo\bon\bni\bit\bto\bor\br Same as -\b-m\bm.
1173                       n\bno\boc\bcl\blo\bob\bbb\bbe\ber\br
1174                               Same as -\b-C\bC.
1175                       n\bno\boe\bex\bxe\bec\bc  Same as -\b-n\bn.
1176                       n\bno\bog\bgl\blo\bob\bb  Same as -\b-f\bf.
1177                       n\bno\bol\blo\bog\bg   Currently ignored.
1178                       n\bno\bot\bti\bif\bfy\by  Same as -\b-b\bb.
1179                       n\bno\bou\bun\bns\bse\bet\bt Same as -\b-u\bu.
1180                       o\bon\bne\bec\bcm\bmd\bd  Same as -\b-t\bt.
1181                       p\bph\bhy\bys\bsi\bic\bca\bal\bl
1182                               Same as -\b-P\bP.
1183                       p\bpi\bip\bpe\bef\bfa\bai\bil\bl
1184                               If set, the return value of a  pipeline  is  the
1185                               value  of  the  last (rightmost) command to exit
1186                               with a non-zero status, or zero if all  commands
1187                               in  the pipeline exit successfully.  This option
1188                               is disabled by default.
1189                       p\bpo\bos\bsi\bix\bx   Change the behavior of b\bba\bas\bsh\bh  where  the  default
1190                               operation  differs  from  the  POSIX standard to
1191                               match the standard (_\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be).  See  S\bSE\bEE\bE  A\bAL\bLS\bSO\bO
1192                               below for a reference to a document that details
1193                               how posix mode affects bash's behavior.
1194                       p\bpr\bri\biv\bvi\bil\ble\beg\bge\bed\bd
1195                               Same as -\b-p\bp.
1196                       v\bve\ber\brb\bbo\bos\bse\be Same as -\b-v\bv.
1197                       v\bvi\bi      Use a vi-style command line  editing  interface.
1198                               This also affects the editing interface used for
1199                               r\bre\bea\bad\bd -\b-e\be.
1200                       x\bxt\btr\bra\bac\bce\be  Same as -\b-x\bx.
1201                       If -\b-o\bo is supplied with no _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, the values of the
1202                       current  options are printed.  If +\b+o\bo is supplied with no
1203                       _\bo_\bp_\bt_\bi_\bo_\bn_\b-_\bn_\ba_\bm_\be, a series of s\bse\bet\bt commands  to  recreate  the
1204                       current  option  settings  is  displayed on the standard
1205                       output.
1206               -\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
1207                       $\b$B\bBA\bAS\bSH\bH_\b_E\bEN\bNV\bV  files  are not processed, shell functions are
1208                       not inherited from the environment, and  the  S\bSH\bHE\bEL\bLL\bLO\bOP\bPT\bTS\bS,
1209                       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
1210                       appear in the environment, are ignored.  If the shell is
1211                       started  with the effective user (group) id not equal to
1212                       the real user (group) id, and the -\b-p\bp option is not  sup-
1213                       plied, these actions are taken and the effective user id
1214                       is set to the real user id.  If the -\b-p\bp  option  is  sup-
1215                       plied  at  startup,  the effective user id is not reset.
1216                       Turning this option off causes the  effective  user  and
1217                       group ids to be set to the real user and group ids.
1218               -\b-t\bt      Exit after reading and executing one command.
1219               -\b-u\bu      Treat unset variables and parameters other than the spe-
1220                       cial parameters "@" and "*" as an error when  performing
1221                       parameter  expansion.   If  expansion is attempted on an
1222                       unset variable or parameter, the shell prints  an  error
1223                       message,  and, if not interactive, exits with a non-zero
1224                       status.
1225               -\b-v\bv      Print shell input lines as they are read.
1226               -\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
1227                       command, s\bse\bel\ble\bec\bct\bt command, or arithmetic f\bfo\bor\br command, dis-
1228                       play the expanded value of P\bPS\bS4\b4, followed by the  command
1229                       and its expanded arguments or associated word list.
1230               -\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
1231                       above).  This is on by default.
1232               -\b-C\bC      If set, b\bba\bas\bsh\bh does not overwrite an  existing  file  with
1233                       the  >\b>,  >\b>&\b&,  and <\b<>\b> redirection operators.  This may be
1234                       overridden when creating output files by using the redi-
1235                       rection operator >\b>|\b| instead of >\b>.
1236               -\b-E\bE      If set, any trap on E\bER\bRR\bR is inherited by shell functions,
1237                       command substitutions, and commands executed in  a  sub-
1238                       shell  environment.  The E\bER\bRR\bR trap is normally not inher-
1239                       ited in such cases.
1240               -\b-H\bH      Enable !\b!  style history substitution.  This option is on
1241                       by default when the shell is interactive.
1242               -\b-P\bP      If  set,  the shell does not resolve symbolic links when
1243                       executing commands such as c\bcd\bd that  change  the  current
1244                       working  directory.   It  uses  the  physical  directory
1245                       structure instead.  By default, b\bba\bas\bsh\bh follows the logical
1246                       chain  of  directories  when  performing  commands which
1247                       change the current directory.
1248               -\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
1249                       shell  functions,  command  substitutions,  and commands
1250                       executed in  a  subshell  environment.   The  D\bDE\bEB\bBU\bUG\bG  and
1251                       R\bRE\bET\bTU\bUR\bRN\bN traps are normally not inherited in such cases.
1252               -\b--\b-      If  no arguments follow this option, then the positional
1253                       parameters are unset.  Otherwise, the positional parame-
1254                       ters  are  set  to  the _\ba_\br_\bgs, even if some of them begin
1255                       with a -\b-.
1256               -\b-       Signal the end of options, cause all remaining  _\ba_\br_\bgs  to
1257                       be assigned to the positional parameters.  The -\b-x\bx and -\b-v\bv
1258                       options are turned off.  If there are no _\ba_\br_\bgs, the posi-
1259                       tional parameters remain unchanged.
1260
1261               The  options are off by default unless otherwise noted.  Using +
1262               rather than - causes  these  options  to  be  turned  off.   The
1263               options  can  also be specified as arguments to an invocation of
1264               the shell.  The current set of options may be found in $\b$-\b-.   The
1265               return status is always true unless an invalid option is encoun-
1266               tered.
1267
1268        s\bsh\bhi\bif\bft\bt [_\bn]
1269               The positional parameters from _\bn+1 ... are renamed  to  $\b$1\b1  .\b..\b..\b..\b.
1270               Parameters  represented  by  the  numbers  $\b$#\b# down to $\b$#\b#-_\bn+1 are
1271               unset.  _\bn must be a non-negative number less than  or  equal  to
1272               $\b$#\b#.   If  _\bn is 0, no parameters are changed.  If _\bn is not given,
1273               it is assumed to be 1.  If _\bn is greater than $\b$#\b#, the  positional
1274               parameters  are  not changed.  The return status is greater than
1275               zero if _\bn is greater than $\b$#\b# or less than zero; otherwise 0.
1276
1277        s\bsh\bho\bop\bpt\bt [-\b-p\bpq\bqs\bsu\bu] [-\b-o\bo] [_\bo_\bp_\bt_\bn_\ba_\bm_\be ...]
1278               Toggle the values of settings controlling optional shell  behav-
1279               ior.   The settings can be either those listed below, or, if the
1280               -\b-o\bo option is used, those available with the -\b-o\bo option to the s\bse\bet\bt
1281               builtin command.  With no options, or with the -\b-p\bp option, a list
1282               of all settable options is  displayed,  with  an  indication  of
1283               whether or not each is set; if _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are supplied, the output
1284               is restricted to those options.  The -\b-p\bp option causes output  to
1285               be  displayed  in  a  form  that  may be reused as input.  Other
1286               options have the following meanings:
1287               -\b-s\bs     Enable (set) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
1288               -\b-u\bu     Disable (unset) each _\bo_\bp_\bt_\bn_\ba_\bm_\be.
1289               -\b-q\bq     Suppresses normal output (quiet mode); the return  status
1290                      indicates whether the _\bo_\bp_\bt_\bn_\ba_\bm_\be is set or unset.  If multi-
1291                      ple _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments are given with -\b-q\bq, the return  sta-
1292                      tus  is zero if all _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs are enabled; non-zero other-
1293                      wise.
1294               -\b-o\bo     Restricts the values of _\bo_\bp_\bt_\bn_\ba_\bm_\be to be those  defined  for
1295                      the -\b-o\bo option to the s\bse\bet\bt builtin.
1296
1297               If  either  -\b-s\bs  or  -\b-u\bu  is used with no _\bo_\bp_\bt_\bn_\ba_\bm_\be arguments, s\bsh\bho\bop\bpt\bt
1298               shows only those options which are set or  unset,  respectively.
1299               Unless  otherwise  noted, the s\bsh\bho\bop\bpt\bt options are disabled (unset)
1300               by default.
1301
1302               The return status when listing options is zero if  all  _\bo_\bp_\bt_\bn_\ba_\bm_\be_\bs
1303               are  enabled,  non-zero  otherwise.   When  setting or unsetting
1304               options, the return status is zero unless an _\bo_\bp_\bt_\bn_\ba_\bm_\be  is  not  a
1305               valid shell option.
1306
1307               The list of s\bsh\bho\bop\bpt\bt options is:
1308
1309               a\bas\bss\bso\boc\bc_\b_e\bex\bxp\bpa\ban\bnd\bd_\b_o\bon\bnc\bce\be
1310                       If  set,  the  shell  suppresses  multiple evaluation of
1311                       associative array subscripts during  arithmetic  expres-
1312                       sion  evaluation, while executing builtins that can per-
1313                       form variable assignments, and while executing  builtins
1314                       that perform array dereferencing.
1315               a\bau\but\bto\boc\bcd\bd  If  set,  a command name that is the name of a directory
1316                       is executed as if it were the argument to  the  c\bcd\bd  com-
1317                       mand.  This option is only used by interactive shells.
1318               c\bcd\bda\bab\bbl\ble\be_\b_v\bva\bar\brs\bs
1319                       If  set,  an  argument to the c\bcd\bd builtin command that is
1320                       not a directory is assumed to be the name of a  variable
1321                       whose value is the directory to change to.
1322               c\bcd\bds\bsp\bpe\bel\bll\bl If set, minor errors in the spelling of a directory com-
1323                       ponent in a c\bcd\bd command will be  corrected.   The  errors
1324                       checked for are transposed characters, a missing charac-
1325                       ter, and one character too many.   If  a  correction  is
1326                       found,  the  corrected filename is printed, and the com-
1327                       mand proceeds.  This option is only used by  interactive
1328                       shells.
1329               c\bch\bhe\bec\bck\bkh\bha\bas\bsh\bh
1330                       If set, b\bba\bas\bsh\bh checks that a command found in the hash ta-
1331                       ble exists before trying to execute  it.   If  a  hashed
1332                       command  no  longer exists, a normal path search is per-
1333                       formed.
1334               c\bch\bhe\bec\bck\bkj\bjo\bob\bbs\bs
1335                       If set, b\bba\bas\bsh\bh lists the status of any stopped and running
1336                       jobs  before  exiting an interactive shell.  If any jobs
1337                       are running, this causes the exit to be deferred until a
1338                       second  exit is attempted without an intervening command
1339                       (see J\bJO\bOB\bB C\bCO\bON\bNT\bTR\bRO\bOL\bL above).   The  shell  always  postpones
1340                       exiting if any jobs are stopped.
1341               c\bch\bhe\bec\bck\bkw\bwi\bin\bns\bsi\biz\bze\be
1342                       If  set, b\bba\bas\bsh\bh checks the window size after each external
1343                       (non-builtin) command and,  if  necessary,  updates  the
1344                       values  of L\bLI\bIN\bNE\bES\bS and C\bCO\bOL\bLU\bUM\bMN\bNS\bS.  This option is enabled by
1345                       default.
1346               c\bcm\bmd\bdh\bhi\bis\bst\bt If set, b\bba\bas\bsh\bh attempts to save all lines of  a  multiple-
1347                       line  command  in  the  same history entry.  This allows
1348                       easy re-editing of multi-line commands.  This option  is
1349                       enabled  by  default,  but only has an effect if command
1350                       history is enabled, as described above under H\bHI\bIS\bST\bTO\bOR\bRY\bY.
1351               c\bco\bom\bmp\bpa\bat\bt3\b31\b1
1352                       If set, b\bba\bas\bsh\bh changes its behavior to that of version 3.1
1353                       with  respect  to quoted arguments to the [\b[[\b[ conditional
1354                       command's =\b=~\b~ operator and locale-specific string compar-
1355                       ison  when  using  the  [\b[[\b[ conditional command's <\b< and >\b>
1356                       operators.  Bash versions prior to  bash-4.1  use  ASCII
1357                       collation and _\bs_\bt_\br_\bc_\bm_\bp(3); bash-4.1 and later use the cur-
1358                       rent locale's collation sequence and _\bs_\bt_\br_\bc_\bo_\bl_\bl(3).
1359               c\bco\bom\bmp\bpa\bat\bt3\b32\b2
1360                       If set, b\bba\bas\bsh\bh changes its behavior to that of version 3.2
1361                       with  respect  to locale-specific string comparison when
1362                       using the [\b[[\b[ conditional command's  <\b<  and  >\b>  operators
1363                       (see  previous  item)  and  the effect of interrupting a
1364                       command list.  Bash versions 3.2  and  earlier  continue
1365                       with  the  next command in the list after one terminates
1366                       due to an interrupt.
1367               c\bco\bom\bmp\bpa\bat\bt4\b40\b0
1368                       If set, b\bba\bas\bsh\bh changes its behavior to that of version 4.0
1369                       with  respect  to locale-specific string comparison when
1370                       using the [\b[[\b[ conditional command's  <\b<  and  >\b>  operators
1371                       (see  description  of c\bco\bom\bmp\bpa\bat\bt3\b31\b1) and the effect of inter-
1372                       rupting a command list.  Bash  versions  4.0  and  later
1373                       interrupt  the  list as if the shell received the inter-
1374                       rupt; previous versions continue with the  next  command
1375                       in the list.
1376               c\bco\bom\bmp\bpa\bat\bt4\b41\b1
1377                       If  set, b\bba\bas\bsh\bh, when in _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be, treats a single quote
1378                       in a double-quoted  parameter  expansion  as  a  special
1379                       character.   The  single quotes must match (an even num-
1380                       ber) and the characters between the  single  quotes  are
1381                       considered  quoted.   This is the behavior of posix mode
1382                       through version 4.1.  The default bash behavior  remains
1383                       as in previous versions.
1384               c\bco\bom\bmp\bpa\bat\bt4\b42\b2
1385                       If  set, b\bba\bas\bsh\bh does not process the replacement string in
1386                       the pattern  substitution  word  expansion  using  quote
1387                       removal.
1388               c\bco\bom\bmp\bpa\bat\bt4\b43\b3
1389                       If  set,  b\bba\bas\bsh\bh  does  not  print a warning message if an
1390                       attempt is made to use a quoted compound  array  assign-
1391                       ment  as  an  argument  to d\bde\bec\bcl\bla\bar\bre\be, makes word expansion
1392                       errors non-fatal errors that cause the  current  command
1393                       to  fail  (the  default  behavior  is to make them fatal
1394                       errors that cause the shell to exit), and does not reset
1395                       the  loop  state when a shell function is executed (this
1396                       allows b\bbr\bre\bea\bak\bk or c\bco\bon\bnt\bti\bin\bnu\bue\be in a shell function  to  affect
1397                       loops in the caller's context).
1398               c\bco\bom\bmp\bpa\bat\bt4\b44\b4
1399                       If   set,   b\bba\bas\bsh\bh  saves  the  positional  parameters  to
1400                       BASH_ARGV and BASH_ARGC before they are used, regardless
1401                       of whether or not extended debugging mode is enabled.
1402               c\bco\bom\bmp\bpl\ble\bet\bte\be_\b_f\bfu\bul\bll\blq\bqu\buo\bot\bte\be
1403                       If  set,  b\bba\bas\bsh\bh  quotes all shell metacharacters in file-
1404                       names and directory names  when  performing  completion.
1405                       If not set, b\bba\bas\bsh\bh removes metacharacters such as the dol-
1406                       lar sign from the set of characters that will be  quoted
1407                       in  completed filenames when these metacharacters appear
1408                       in shell variable references in words to  be  completed.
1409                       This  means  that  dollar  signs  in variable names that
1410                       expand to directories will not be quoted;  however,  any
1411                       dollar  signs appearing in filenames will not be quoted,
1412                       either.  This is active only when bash  is  using  back-
1413                       slashes  to quote completed filenames.  This variable is
1414                       set by default, which is the default  bash  behavior  in
1415                       versions through 4.2.
1416               d\bdi\bir\bre\bex\bxp\bpa\ban\bnd\bd
1417                       If  set,  b\bba\bas\bsh\bh replaces directory names with the results
1418                       of word expansion when performing  filename  completion.
1419                       This  changes  the contents of the readline editing buf-
1420                       fer.  If not set, b\bba\bas\bsh\bh attempts  to  preserve  what  the
1421                       user typed.
1422               d\bdi\bir\brs\bsp\bpe\bel\bll\bl
1423                       If  set,  b\bba\bas\bsh\bh attempts spelling correction on directory
1424                       names during word completion if the directory name  ini-
1425                       tially supplied does not exist.
1426               d\bdo\bot\btg\bgl\blo\bob\bb If  set, b\bba\bas\bsh\bh includes filenames beginning with a `.' in
1427                       the results of pathname expansion.  The filenames  `\b``\b`.\b.'\b''\b'
1428                       and  `\b``\b`.\b..\b.'\b''\b'   must always be matched explicitly, even if
1429                       d\bdo\bot\btg\bgl\blo\bob\bb is set.
1430               e\bex\bxe\bec\bcf\bfa\bai\bil\bl
1431                       If set, a non-interactive shell will not exit if it can-
1432                       not  execute  the  file  specified as an argument to the
1433                       e\bex\bxe\bec\bc builtin command.  An  interactive  shell  does  not
1434                       exit if e\bex\bxe\bec\bc fails.
1435               e\bex\bxp\bpa\ban\bnd\bd_\b_a\bal\bli\bia\bas\bse\bes\bs
1436                       If  set,  aliases  are expanded as described above under
1437                       A\bAL\bLI\bIA\bAS\bSE\bES\bS.  This option is enabled by default for interac-
1438                       tive shells.
1439               e\bex\bxt\btd\bde\beb\bbu\bug\bg
1440                       If  set  at  shell  invocation,  arrange  to execute the
1441                       debugger profile before the shell starts,  identical  to
1442                       the  -\b--\b-d\bde\beb\bbu\bug\bgg\bge\ber\br option.  If set after invocation, behav-
1443                       ior intended for use by debuggers is enabled:
1444                       1\b1.\b.     The -\b-F\bF option to the d\bde\bec\bcl\bla\bar\bre\be builtin displays the
1445                              source file name and line number corresponding to
1446                              each function name supplied as an argument.
1447                       2\b2.\b.     If the command run by the D\bDE\bEB\bBU\bUG\bG  trap  returns  a
1448                              non-zero  value,  the next command is skipped and
1449                              not executed.
1450                       3\b3.\b.     If the command run by the D\bDE\bEB\bBU\bUG\bG  trap  returns  a
1451                              value  of 2, and the shell is executing in a sub-
1452                              routine (a shell function or a shell script  exe-
1453                              cuted  by  the  .\b.  or s\bso\bou\bur\brc\bce\be builtins), the shell
1454                              simulates a call to r\bre\bet\btu\bur\brn\bn.
1455                       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
1456                              in their descriptions above.
1457                       5\b5.\b.     Function  tracing  is  enabled: command substitu-
1458                              tion, shell functions, and subshells invoked with
1459                              (\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.
1460                       6\b6.\b.     Error  tracing  is enabled: command substitution,
1461                              shell functions, and  subshells  invoked  with  (\b(
1462                              _\bc_\bo_\bm_\bm_\ba_\bn_\bd )\b) inherit the E\bER\bRR\bR trap.
1463               e\bex\bxt\btg\bgl\blo\bob\bb If set, the extended pattern matching features described
1464                       above under P\bPa\bat\bth\bhn\bna\bam\bme\be E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn are enabled.
1465               e\bex\bxt\btq\bqu\buo\bot\bte\be
1466                       If set, $\b$'_\bs_\bt_\br_\bi_\bn_\bg' and  $\b$"_\bs_\bt_\br_\bi_\bn_\bg"  quoting  is  performed
1467                       within   $\b${\b{_\bp_\ba_\br_\ba_\bm_\be_\bt_\be_\br}\b}   expansions  enclosed  in  double
1468                       quotes.  This option is enabled by default.
1469               f\bfa\bai\bil\blg\bgl\blo\bob\bb
1470                       If set, patterns which fail to  match  filenames  during
1471                       pathname expansion result in an expansion error.
1472               f\bfo\bor\brc\bce\be_\b_f\bfi\big\bgn\bno\bor\bre\be
1473                       If  set,  the  suffixes  specified  by the F\bFI\bIG\bGN\bNO\bOR\bRE\bE shell
1474                       variable cause words to be ignored when performing  word
1475                       completion even if the ignored words are the only possi-
1476                       ble  completions.   See  S\bSH\bHE\bEL\bLL\bL  V\bVA\bAR\bRI\bIA\bAB\bBL\bLE\bES\bS  above  for  a
1477                       description  of  F\bFI\bIG\bGN\bNO\bOR\bRE\bE.   This  option  is  enabled by
1478                       default.
1479               g\bgl\blo\bob\bba\bas\bsc\bci\bii\bir\bra\ban\bng\bge\bes\bs
1480                       If set,  range  expressions  used  in  pattern  matching
1481                       bracket  expressions (see P\bPa\bat\btt\bte\ber\brn\bn M\bMa\bat\btc\bch\bhi\bin\bng\bg above) behave
1482                       as if in the traditional C locale when  performing  com-
1483                       parisons.   That  is,  the  current  locale's  collating
1484                       sequence is not taken into account, so b\bb will  not  col-
1485                       late  between  A\bA  and  B\bB,  and upper-case and lower-case
1486                       ASCII characters will collate together.
1487               g\bgl\blo\bob\bbs\bst\bta\bar\br
1488                       If set, the pattern *\b**\b* used in a pathname expansion con-
1489                       text  will  match all files and zero or more directories
1490                       and subdirectories.  If the pattern is followed by a  /\b/,
1491                       only directories and subdirectories match.
1492               g\bgn\bnu\bu_\b_e\ber\brr\brf\bfm\bmt\bt
1493                       If set, shell error messages are written in the standard
1494                       GNU error message format.
1495               h\bhi\bis\bst\bta\bap\bpp\bpe\ben\bnd\bd
1496                       If set, the history list is appended to the  file  named
1497                       by  the  value  of  the H\bHI\bIS\bST\bTF\bFI\bIL\bLE\bE variable when the shell
1498                       exits, rather than overwriting the file.
1499               h\bhi\bis\bst\btr\bre\bee\bed\bdi\bit\bt
1500                       If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, a user is given  the
1501                       opportunity to re-edit a failed history substitution.
1502               h\bhi\bis\bst\btv\bve\ber\bri\bif\bfy\by
1503                       If  set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, the results of his-
1504                       tory substitution are  not  immediately  passed  to  the
1505                       shell  parser.   Instead,  the  resulting line is loaded
1506                       into the r\bre\bea\bad\bdl\bli\bin\bne\be editing buffer, allowing further modi-
1507                       fication.
1508               h\bho\bos\bst\btc\bco\bom\bmp\bpl\ble\bet\bte\be
1509                       If set, and r\bre\bea\bad\bdl\bli\bin\bne\be is being used, b\bba\bas\bsh\bh will attempt to
1510                       perform hostname completion when a word containing  a  @\b@
1511                       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
1512                       above).  This is enabled by default.
1513               h\bhu\bup\bpo\bon\bne\bex\bxi\bit\bt
1514                       If set, b\bba\bas\bsh\bh will send S\bSI\bIG\bGH\bHU\bUP\bP to all jobs when an inter-
1515                       active login shell exits.
1516               i\bin\bnh\bhe\ber\bri\bit\bt_\b_e\ber\brr\bre\bex\bxi\bit\bt
1517                       If  set,  command substitution inherits the value of the
1518                       e\ber\brr\bre\bex\bxi\bit\bt option, instead of unsetting it in the  subshell
1519                       environment.   This option is enabled when _\bp_\bo_\bs_\bi_\bx _\bm_\bo_\bd_\be is
1520                       enabled.
1521               i\bin\bnt\bte\ber\bra\bac\bct\bti\biv\bve\be_\b_c\bco\bom\bmm\bme\ben\bnt\bts\bs
1522                       If set, allow a word beginning with #\b# to cause that word
1523                       and  all remaining characters on that line to be ignored
1524                       in an interactive  shell  (see  C\bCO\bOM\bMM\bME\bEN\bNT\bTS\bS  above).   This
1525                       option is enabled by default.
1526               l\bla\bas\bst\btp\bpi\bip\bpe\be
1527                       If  set,  and  job control is not active, the shell runs
1528                       the last command of a pipeline not executed in the back-
1529                       ground in the current shell environment.
1530               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
1531                       commands are saved to the history with embedded newlines
1532                       rather than using semicolon separators where possible.
1533               l\blo\boc\bca\bal\blv\bva\bar\br_\b_i\bin\bnh\bhe\ber\bri\bit\bt
1534                       If set, local variables inherit the value and attributes
1535                       of a variable of the same name that exists at a previous
1536                       scope  before  any  new  value is assigned.  The nameref
1537                       attribute is not inherited.
1538               l\blo\boc\bca\bal\blv\bva\bar\br_\b_u\bun\bns\bse\bet\bt
1539                       If set, calling u\bun\bns\bse\bet\bt on  local  variables  in  previous
1540                       function  scopes  marks  them so subsequent lookups find
1541                       them unset until that function returns. This is  identi-
1542                       cal  to the behavior of unsetting local variables at the
1543                       current function scope.
1544               l\blo\bog\bgi\bin\bn_\b_s\bsh\bhe\bel\bll\bl
1545                       The shell sets this option if it is started as  a  login
1546                       shell  (see  I\bIN\bNV\bVO\bOC\bCA\bAT\bTI\bIO\bON\bN  above).   The  value may not be
1547                       changed.
1548               m\bma\bai\bil\blw\bwa\bar\brn\bn
1549                       If set, and a file that b\bba\bas\bsh\bh is checking  for  mail  has
1550                       been  accessed  since  the last time it was checked, the
1551                       message ``The mail in _\bm_\ba_\bi_\bl_\bf_\bi_\bl_\be has been read''  is  dis-
1552                       played.
1553               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
1554                       If  set,  and  r\bre\bea\bad\bdl\bli\bin\bne\be  is  being  used,  b\bba\bas\bsh\bh will not
1555                       attempt to search the P\bPA\bAT\bTH\bH for possible completions when
1556                       completion is attempted on an empty line.
1557               n\bno\boc\bca\bas\bse\beg\bgl\blo\bob\bb
1558                       If  set,  b\bba\bas\bsh\bh  matches  filenames in a case-insensitive
1559                       fashion when performing pathname expansion (see P\bPa\bat\bth\bhn\bna\bam\bme\be
1560                       E\bEx\bxp\bpa\ban\bns\bsi\bio\bon\bn above).
1561               n\bno\boc\bca\bas\bse\bem\bma\bat\btc\bch\bh
1562                       If  set,  b\bba\bas\bsh\bh  matches  patterns  in a case-insensitive
1563                       fashion when performing matching while executing c\bca\bas\bse\be or
1564                       [\b[[\b[ conditional commands, when performing pattern substi-
1565                       tution word expansions, or when filtering possible  com-
1566                       pletions as part of programmable completion.
1567               n\bnu\bul\bll\blg\bgl\blo\bob\bb
1568                       If  set,  b\bba\bas\bsh\bh allows patterns which match no files (see
1569                       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,
1570                       rather than themselves.
1571               p\bpr\bro\bog\bgc\bco\bom\bmp\bp
1572                       If set, the programmable completion facilities (see P\bPr\bro\bo-\b-
1573                       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
1574                       enabled by default.
1575               p\bpr\bro\bog\bgc\bco\bom\bmp\bp_\b_a\bal\bli\bia\bas\bs
1576                       If  set,  and  programmable  completion is enabled, b\bba\bas\bsh\bh
1577                       treats a command name that doesn't have any  completions
1578                       as  a possible alias and attempts alias expansion. If it
1579                       has an  alias,  b\bba\bas\bsh\bh  attempts  programmable  completion
1580                       using  the  command  word  resulting  from  the expanded
1581                       alias.
1582               p\bpr\bro\bom\bmp\bpt\btv\bva\bar\brs\bs
1583                       If set, prompt strings undergo parameter expansion, com-
1584                       mand   substitution,  arithmetic  expansion,  and  quote
1585                       removal after being expanded as described  in  P\bPR\bRO\bOM\bMP\bPT\bTI\bIN\bNG\bG
1586                       above.  This option is enabled by default.
1587               r\bre\bes\bst\btr\bri\bic\bct\bte\bed\bd_\b_s\bsh\bhe\bel\bll\bl
1588                       The   shell  sets  this  option  if  it  is  started  in
1589                       restricted mode (see R\bRE\bES\bST\bTR\bRI\bIC\bCT\bTE\bED\bD S\bSH\bHE\bEL\bLL\bL below).  The value
1590                       may  not be changed.  This is not reset when the startup
1591                       files are executed, allowing the startup files  to  dis-
1592                       cover whether or not a shell is restricted.
1593               s\bsh\bhi\bif\bft\bt_\b_v\bve\ber\brb\bbo\bos\bse\be
1594                       If  set,  the s\bsh\bhi\bif\bft\bt builtin prints an error message when
1595                       the shift count exceeds the number of positional parame-
1596                       ters.
1597               s\bso\bou\bur\brc\bce\bep\bpa\bat\bth\bh
1598                       If set, the s\bso\bou\bur\brc\bce\be (.\b.) builtin uses the value of P\bPA\bAT\bTH\bH to
1599                       find the directory containing the file  supplied  as  an
1600                       argument.  This option is enabled by default.
1601               x\bxp\bpg\bg_\b_e\bec\bch\bho\bo
1602                       If   set,  the  e\bec\bch\bho\bo  builtin  expands  backslash-escape
1603                       sequences by default.
1604
1605        s\bsu\bus\bsp\bpe\ben\bnd\bd [-\b-f\bf]
1606               Suspend the execution of this shell until it receives a  S\bSI\bIG\bGC\bCO\bON\bNT\bT
1607               signal.  A login shell cannot be suspended; the -\b-f\bf option can be
1608               used to override this and force the suspension.  The return sta-
1609               tus  is  0  unless the shell is a login shell and -\b-f\bf is not sup-
1610               plied, or if job control is not enabled.
1611
1612        t\bte\bes\bst\bt _\be_\bx_\bp_\br
1613        [\b[ _\be_\bx_\bp_\br ]\b]
1614               Return a status of 0 (true) or 1 (false) depending on the evalu-
1615               ation of the conditional expression _\be_\bx_\bp_\br.  Each operator and op-
1616               erand must be a separate argument.  Expressions are composed  of
1617               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.
1618               t\bte\bes\bst\bt does not accept any options, nor does it accept and  ignore
1619               an argument of -\b--\b- as signifying the end of options.
1620
1621               Expressions  may  be  combined  using  the  following operators,
1622               listed  in  decreasing  order  of  precedence.   The  evaluation
1623               depends  on the number of arguments; see below.  Operator prece-
1624               dence is used when there are five or more arguments.
1625               !\b! _\be_\bx_\bp_\br True if _\be_\bx_\bp_\br is false.
1626               (\b( _\be_\bx_\bp_\br )\b)
1627                      Returns the value of _\be_\bx_\bp_\br.  This may be used to  override
1628                      the normal precedence of operators.
1629               _\be_\bx_\bp_\br_\b1 -a\ba _\be_\bx_\bp_\br_\b2
1630                      True if both _\be_\bx_\bp_\br_\b1 and _\be_\bx_\bp_\br_\b2 are true.
1631               _\be_\bx_\bp_\br_\b1 -o\bo _\be_\bx_\bp_\br_\b2
1632                      True if either _\be_\bx_\bp_\br_\b1 or _\be_\bx_\bp_\br_\b2 is true.
1633
1634               t\bte\bes\bst\bt and [\b[ evaluate conditional expressions using a set of rules
1635               based on the number of arguments.
1636
1637               0 arguments
1638                      The expression is false.
1639               1 argument
1640                      The expression is true if and only if the argument is not
1641                      null.
1642               2 arguments
1643                      If the first argument is !\b!, the expression is true if and
1644                      only if the second argument is null.  If the first  argu-
1645                      ment  is  one  of  the unary conditional operators listed
1646                      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
1647                      true if the unary test is true.  If the first argument is
1648                      not a valid unary conditional operator, the expression is
1649                      false.
1650               3 arguments
1651                      The following conditions are applied in the order listed.
1652                      If the second argument is one of the  binary  conditional
1653                      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
1654                      result of the expression is the result of the binary test
1655                      using  the first and third arguments as operands.  The -\b-a\ba
1656                      and -\b-o\bo operators are  considered  binary  operators  when
1657                      there  are  three arguments.  If the first argument is !\b!,
1658                      the value is the negation of the two-argument test  using
1659                      the second and third arguments.  If the first argument is
1660                      exactly (\b( and the third argument is exactly )\b), the result
1661                      is  the one-argument test of the second argument.  Other-
1662                      wise, the expression is false.
1663               4 arguments
1664                      If the first argument is !\b!, the result is the negation of
1665                      the  three-argument  expression composed of the remaining
1666                      arguments.  Otherwise, the expression is parsed and eval-
1667                      uated  according  to  precedence  using  the rules listed
1668                      above.
1669               5 or more arguments
1670                      The expression  is  parsed  and  evaluated  according  to
1671                      precedence using the rules listed above.
1672
1673               When  used  with  t\bte\bes\bst\bt  or [\b[, the <\b< and >\b> operators sort lexico-
1674               graphically using ASCII ordering.
1675
1676        t\bti\bim\bme\bes\bs  Print the accumulated user and system times for  the  shell  and
1677               for processes run from the shell.  The return status is 0.
1678
1679        t\btr\bra\bap\bp [-\b-l\blp\bp] [[_\ba_\br_\bg] _\bs_\bi_\bg_\bs_\bp_\be_\bc ...]
1680               The  command  _\ba_\br_\bg  is  to  be  read  and executed when the shell
1681               receives signal(s) _\bs_\bi_\bg_\bs_\bp_\be_\bc.  If _\ba_\br_\bg is absent (and  there  is  a
1682               single  _\bs_\bi_\bg_\bs_\bp_\be_\bc)  or  -\b-,  each  specified signal is reset to its
1683               original disposition (the value it  had  upon  entrance  to  the
1684               shell).   If _\ba_\br_\bg is the null string the signal specified by each
1685               _\bs_\bi_\bg_\bs_\bp_\be_\bc is ignored by the shell and by the commands it  invokes.
1686               If  _\ba_\br_\bg  is  not present and -\b-p\bp has been supplied, then the trap
1687               commands associated with each  _\bs_\bi_\bg_\bs_\bp_\be_\bc  are  displayed.   If  no
1688               arguments  are  supplied or if only -\b-p\bp is given, t\btr\bra\bap\bp prints the
1689               list of commands associated with each  signal.   The  -\b-l\bl  option
1690               causes  the shell to print a list of signal names and their cor-
1691               responding numbers.   Each  _\bs_\bi_\bg_\bs_\bp_\be_\bc  is  either  a  signal  name
1692               defined  in  <_\bs_\bi_\bg_\bn_\ba_\bl_\b._\bh>,  or  a signal number.  Signal names are
1693               case insensitive and the S\bSI\bIG\bG prefix is optional.
1694
1695               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
1696               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-
1697               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,
1698               _\bs_\be_\bl_\be_\bc_\bt  command,  every  arithmetic  _\bf_\bo_\br command, and before the
1699               first command executes in a shell function  (see  S\bSH\bHE\bEL\bLL\bL  G\bGR\bRA\bAM\bMM\bMA\bAR\bR
1700               above).   Refer to the description of the e\bex\bxt\btd\bde\beb\bbu\bug\bg option to the
1701               s\bsh\bho\bop\bpt\bt builtin for details of its effect on the D\bDE\bEB\bBU\bUG\bG trap.  If a
1702               _\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
1703               function or a script executed with the .\b. or s\bso\bou\bur\brc\bce\be builtins fin-
1704               ishes executing.
1705
1706               If  a  _\bs_\bi_\bg_\bs_\bp_\be_\bc  is  E\bER\bRR\bR,  the command _\ba_\br_\bg is executed whenever a
1707               pipeline (which may consist of a single simple command), a list,
1708               or a compound command returns a non-zero exit status, subject to
1709               the following conditions.  The E\bER\bRR\bR trap is not executed  if  the
1710               failed command is part of the command list immediately following
1711               a w\bwh\bhi\bil\ble\be or u\bun\bnt\bti\bil\bl keyword, part of the test in an  _\bi_\bf  statement,
1712               part of a command executed in a &\b&&\b& or |\b||\b| list except the command
1713               following the final &\b&&\b& or |\b||\b|, any command in a pipeline but  the
1714               last,  or  if the command's return value is being inverted using
1715               !\b!.  These are the same conditions obeyed  by  the  e\ber\brr\bre\bex\bxi\bit\bt  (-\b-e\be)
1716               option.
1717
1718               Signals  ignored  upon  entry  to the shell cannot be trapped or
1719               reset.  Trapped signals that are not being ignored are reset  to
1720               their original values in a subshell or subshell environment when
1721               one is created.  The return status is false if  any  _\bs_\bi_\bg_\bs_\bp_\be_\bc  is
1722               invalid; otherwise t\btr\bra\bap\bp returns true.
1723
1724        t\bty\byp\bpe\be [-\b-a\baf\bft\btp\bpP\bP] _\bn_\ba_\bm_\be [_\bn_\ba_\bm_\be ...]
1725               With  no options, indicate how each _\bn_\ba_\bm_\be would be interpreted if
1726               used as a command name.  If the -\b-t\bt option is used, t\bty\byp\bpe\be prints a
1727               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
1728               _\bf_\bi_\bl_\be if  _\bn_\ba_\bm_\be  is  an  alias,  shell  reserved  word,  function,
1729               builtin,  or disk file, respectively.  If the _\bn_\ba_\bm_\be is not found,
1730               then nothing  is  printed,  and  an  exit  status  of  false  is
1731               returned.   If  the  -\b-p\bp  option is used, t\bty\byp\bpe\be either returns the
1732               name of the disk file that would be executed if _\bn_\ba_\bm_\be were speci-
1733               fied as a command name, or nothing if ``type -t name'' would not
1734               return _\bf_\bi_\bl_\be.  The -\b-P\bP option forces a P\bPA\bAT\bTH\bH search for each  _\bn_\ba_\bm_\be,
1735               even if ``type -t name'' would not return _\bf_\bi_\bl_\be.  If a command is
1736               hashed, -\b-p\bp and -\b-P\bP print the hashed value, which is not necessar-
1737               ily  the  file  that appears first in P\bPA\bAT\bTH\bH.  If the -\b-a\ba option is
1738               used, t\bty\byp\bpe\be prints all of the places that contain  an  executable
1739               named _\bn_\ba_\bm_\be.  This includes aliases and functions, if and only if
1740               the -\b-p\bp option is not also used.  The table of hashed commands is
1741               not  consulted  when  using  -\b-a\ba.  The -\b-f\bf option suppresses shell
1742               function lookup, as with the c\bco\bom\bmm\bma\ban\bnd\bd builtin.  t\bty\byp\bpe\be returns true
1743               if all of the arguments are found, false if any are not found.
1744
1745        u\bul\bli\bim\bmi\bit\bt [-\b-H\bHS\bSa\bab\bbc\bcd\bde\bef\bfi\bik\bkl\blm\bmn\bnp\bpq\bqr\brs\bst\btu\buv\bvx\bxP\bPT\bT [_\bl_\bi_\bm_\bi_\bt]]
1746               Provides  control  over the resources available to the shell and
1747               to processes started by it, on systems that allow such  control.
1748               The -\b-H\bH and -\b-S\bS options specify that the hard or soft limit is set
1749               for the given resource.  A hard limit cannot be increased  by  a
1750               non-root  user  once it is set; a soft limit may be increased up
1751               to the value of the hard limit.  If neither -\b-H\bH nor -\b-S\bS is  speci-
1752               fied, both the soft and hard limits are set.  The value of _\bl_\bi_\bm_\bi_\bt
1753               can be a number in the unit specified for the resource or one of
1754               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
1755               current hard limit,  the  current  soft  limit,  and  no  limit,
1756               respectively.   If  _\bl_\bi_\bm_\bi_\bt  is  omitted, the current value of the
1757               soft limit of the resource is printed, unless the -\b-H\bH  option  is
1758               given.  When more than one resource is specified, the limit name
1759               and unit are printed before the value.  Other options are inter-
1760               preted as follows:
1761               -\b-a\ba     All current limits are reported
1762               -\b-b\bb     The maximum socket buffer size
1763               -\b-c\bc     The maximum size of core files created
1764               -\b-d\bd     The maximum size of a process's data segment
1765               -\b-e\be     The maximum scheduling priority ("nice")
1766               -\b-f\bf     The  maximum  size  of files written by the shell and its
1767                      children
1768               -\b-i\bi     The maximum number of pending signals
1769               -\b-k\bk     The maximum number of kqueues that may be allocated
1770               -\b-l\bl     The maximum size that may be locked into memory
1771               -\b-m\bm     The maximum resident set size (many systems do not  honor
1772                      this limit)
1773               -\b-n\bn     The maximum number of open file descriptors (most systems
1774                      do not allow this value to be set)
1775               -\b-p\bp     The pipe size in 512-byte blocks (this may not be set)
1776               -\b-q\bq     The maximum number of bytes in POSIX message queues
1777               -\b-r\br     The maximum real-time scheduling priority
1778               -\b-s\bs     The maximum stack size
1779               -\b-t\bt     The maximum amount of cpu time in seconds
1780               -\b-u\bu     The maximum number of processes  available  to  a  single
1781                      user
1782               -\b-v\bv     The  maximum  amount  of  virtual memory available to the
1783                      shell and, on some systems, to its children
1784               -\b-x\bx     The maximum number of file locks
1785               -\b-P\bP     The maximum number of pseudoterminals
1786               -\b-T\bT     The maximum number of threads
1787
1788               If _\bl_\bi_\bm_\bi_\bt is given, and the -\b-a\ba option is not used, _\bl_\bi_\bm_\bi_\bt  is  the
1789               new  value  of  the  specified resource.  If no option is given,
1790               then -\b-f\bf is assumed.  Values are in 1024-byte increments,  except
1791               for  -\b-t\bt,  which is in seconds; -\b-p\bp, which is in units of 512-byte
1792               blocks; -\b-P\bP, -\b-T\bT, -\b-b\bb, -\b-k\bk, -\b-n\bn, and -\b-u\bu, which are  unscaled  values;
1793               and, when in posix mode, -\b-c\bc and -\b-f\bf, which are in 512-byte incre-
1794               ments.  The return status is 0 unless an invalid option or argu-
1795               ment is supplied, or an error occurs while setting a new limit.
1796
1797        u\bum\bma\bas\bsk\bk [-\b-p\bp] [-\b-S\bS] [_\bm_\bo_\bd_\be]
1798               The user file-creation mask is set to _\bm_\bo_\bd_\be.  If _\bm_\bo_\bd_\be begins with
1799               a digit, it is interpreted as an octal number; otherwise  it  is
1800               interpreted  as a symbolic mode mask similar to that accepted by
1801               _\bc_\bh_\bm_\bo_\bd(1).  If _\bm_\bo_\bd_\be is omitted, the current value of the mask  is
1802               printed.   The  -\b-S\bS  option causes the mask to be printed in sym-
1803               bolic form; the default output is an octal number.   If  the  -\b-p\bp
1804               option is supplied, and _\bm_\bo_\bd_\be is omitted, the output is in a form
1805               that may be reused as input.  The return status is 0 if the mode
1806               was  successfully  changed  or if no _\bm_\bo_\bd_\be argument was supplied,
1807               and false otherwise.
1808
1809        u\bun\bna\bal\bli\bia\bas\bs [-a\ba] [_\bn_\ba_\bm_\be ...]
1810               Remove each _\bn_\ba_\bm_\be from the list of defined  aliases.   If  -\b-a\ba  is
1811               supplied,  all  alias definitions are removed.  The return value
1812               is true unless a supplied _\bn_\ba_\bm_\be is not a defined alias.
1813
1814        u\bun\bns\bse\bet\bt [-f\bfv\bv] [-n\bn] [_\bn_\ba_\bm_\be ...]
1815               For each _\bn_\ba_\bm_\be, remove the corresponding  variable  or  function.
1816               If the -\b-v\bv option is given, each _\bn_\ba_\bm_\be refers to a shell variable,
1817               and that variable is removed.  Read-only variables  may  not  be
1818               unset.   If  -\b-f\bf  is specified, each _\bn_\ba_\bm_\be refers to a shell func-
1819               tion, and the function definition is removed.  If the -\b-n\bn  option
1820               is  supplied, and _\bn_\ba_\bm_\be is a variable with the _\bn_\ba_\bm_\be_\br_\be_\bf attribute,
1821               _\bn_\ba_\bm_\be will be unset rather than the variable it  references.   -\b-n\bn
1822               has  no  effect if the -\b-f\bf option is supplied.  If no options are
1823               supplied, each _\bn_\ba_\bm_\be refers to a variable; if there is  no  vari-
1824               able  by  that name, any function with that name is unset.  Each
1825               unset variable or  function  is  removed  from  the  environment
1826               passed  to subsequent commands.  If any of C\bCO\bOM\bMP\bP_\b_W\bWO\bOR\bRD\bDB\bBR\bRE\bEA\bAK\bKS\bS, R\bRA\bAN\bN-\b-
1827               D\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
1828               unset, they lose their special properties, even if they are sub-
1829               sequently reset.  The exit status is true unless a _\bn_\ba_\bm_\be is read-
1830               only.
1831
1832        w\bwa\bai\bit\bt [-\b-f\bfn\bn] [_\bi_\bd _\b._\b._\b.]
1833               Wait for each specified child process and return its termination
1834               status.  Each _\bi_\bd may be a process ID or a job specification;  if
1835               a  job  spec  is given, all processes in that job's pipeline are
1836               waited for.  If _\bi_\bd is not given, all currently active child pro-
1837               cesses are waited for, and the return status is zero.  If the -\b-n\bn
1838               option is supplied, w\bwa\bai\bit\bt waits for  any  job  to  terminate  and
1839               returns  its exit status.  If the -\b-f\bf option is supplied, and job
1840               control is enabled, w\bwa\bai\bit\bt forces _\bi_\bd to terminate before returning
1841               its  status, instead of returning when it changes status.  If _\bi_\bd
1842               specifies a non-existent process or job, the  return  status  is
1843               127.   Otherwise,  the  return  status is the exit status of the
1844               last process or job waited for.
1845
1846 S\bSE\bEE\bE A\bAL\bLS\bSO\bO
1847        bash(1), sh(1)
1848
1849
1850
1851 GNU Bash 5.0                      2004 Apr 20                 BASH_BUILTINS(1)