BASH_BUILTINS(1)            General Commands Manual           BASH_BUILTINS(1)



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

BBAASSHH BBUUIILLTTIINN CCOOMMMMAANNDDSS
       Unless otherwise noted, each builtin command documented in this section
       as accepting options preceded by -- accepts ---- to signify the end of the
       options.  The ::, ttrruuee, ffaallssee, and tteesstt/[[ builtins do not accept options
       and do not treat ---- specially.  The eexxiitt, llooggoouutt, rreettuurrnn,  bbrreeaakk,  ccoonn--
       ttiinnuuee,  lleett,  and sshhiifftt builtins accept and process arguments beginning
       with -- without requiring ----.  Other builtins that accept arguments  but
       are  not  specified  as accepting options interpret arguments beginning
       with -- as invalid options and require ---- to  prevent  this  interpreta-
       tion.
       :: [_a_r_g_u_m_e_n_t_s]
              No  effect;  the command does nothing beyond expanding _a_r_g_u_m_e_n_t_s
              and performing any specified redirections.  The return status is
              zero.

        ..  _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s]
       ssoouurrccee _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s]
              Read  and  execute  commands  from _f_i_l_e_n_a_m_e in the current shell
              environment and return the exit status of the last command  exe-
              cuted  from  _f_i_l_e_n_a_m_e.   If  _f_i_l_e_n_a_m_e  does not contain a slash,
              filenames in PPAATTHH are used  to  find  the  directory  containing
              _f_i_l_e_n_a_m_e.  The file searched for in PPAATTHH need not be executable.
              When bbaasshh is  not  in  _p_o_s_i_x  _m_o_d_e,  the  current  directory  is
              searched  if no file is found in PPAATTHH.  If the ssoouurrcceeppaatthh option
              to the sshhoopptt builtin command is turned  off,  the  PPAATTHH  is  not
              searched.   If any _a_r_g_u_m_e_n_t_s are supplied, they become the posi-
              tional parameters when  _f_i_l_e_n_a_m_e  is  executed.   Otherwise  the
              positional  parameters  are  unchanged.   If  the  --TT  option is
              enabled, ssoouurrccee inherits any trap on DDEEBBUUGG; if it  is  not,  any
              DDEEBBUUGG  trap  string  is  saved  and  restored around the call to
              ssoouurrccee, and ssoouurrccee unsets the DDEEBBUUGG trap while it executes.   If
              --TT  is not set, and the sourced file changes the DDEEBBUUGG trap, the
              new value is retained when ssoouurrccee completes.  The return  status
              is the status of the last command exited within the script (0 if
              no commands are executed), and false if _f_i_l_e_n_a_m_e is not found or
              cannot be read.

       aalliiaass [--pp] [_n_a_m_e[=_v_a_l_u_e] ...]
              AAlliiaass with no arguments or with the --pp option prints the list of
              aliases in the form aalliiaass _n_a_m_e=_v_a_l_u_e on standard  output.   When
              arguments  are supplied, an alias is defined for each _n_a_m_e whose
              _v_a_l_u_e is given.  A trailing space in _v_a_l_u_e causes the next  word
              to be checked for alias substitution when the alias is expanded.
              For each _n_a_m_e in the argument list for which no  _v_a_l_u_e  is  sup-
              plied,  the  name  and  value  of  the  alias is printed.  AAlliiaass
              returns true unless a _n_a_m_e is given for which no alias has  been
              defined.

       bbgg [_j_o_b_s_p_e_c ...]
              Resume  each  suspended  job _j_o_b_s_p_e_c in the background, as if it
              had been started with &&.  If _j_o_b_s_p_e_c is not present, the shell's
              notion  of the _c_u_r_r_e_n_t _j_o_b is used.  bbgg _j_o_b_s_p_e_c returns 0 unless
              run when job control is disabled or, when run with  job  control
              enabled,  any  specified  _j_o_b_s_p_e_c  was  not found or was started
              without job control.

       bbiinndd [--mm _k_e_y_m_a_p] [--llppssvvPPSSVVXX]
       bbiinndd [--mm _k_e_y_m_a_p] [--qq _f_u_n_c_t_i_o_n] [--uu _f_u_n_c_t_i_o_n] [--rr _k_e_y_s_e_q]
       bbiinndd [--mm _k_e_y_m_a_p] --ff _f_i_l_e_n_a_m_e
       bbiinndd [--mm _k_e_y_m_a_p] --xx _k_e_y_s_e_q:_s_h_e_l_l_-_c_o_m_m_a_n_d
       bbiinndd [--mm _k_e_y_m_a_p] _k_e_y_s_e_q:_f_u_n_c_t_i_o_n_-_n_a_m_e
       bbiinndd [--mm _k_e_y_m_a_p] _k_e_y_s_e_q:_r_e_a_d_l_i_n_e_-_c_o_m_m_a_n_d
              Display current rreeaaddlliinnee key and function bindings, bind  a  key
              sequence  to  a  rreeaaddlliinnee  function  or macro, or set a rreeaaddlliinnee
              variable.  Each non-option argument is a  command  as  it  would
              appear  in  _._i_n_p_u_t_r_c, but each binding or command must be passed
              as a separate argument; e.g.,  '"\C-x\C-r":  re-read-init-file'.
              Options, if supplied, have the following meanings:
              --mm _k_e_y_m_a_p
                     Use _k_e_y_m_a_p as the keymap to be affected by the subsequent
                     bindings.  Acceptable _k_e_y_m_a_p names are _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_-
                     _d_a_r_d_,  _e_m_a_c_s_-_m_e_t_a_,  _e_m_a_c_s_-_c_t_l_x_,  _v_i_, _v_i_-_m_o_v_e_, _v_i_-_c_o_m_m_a_n_d,
                     and _v_i_-_i_n_s_e_r_t.  _v_i is equivalent to  _v_i_-_c_o_m_m_a_n_d  (_v_i_-_m_o_v_e
                     is  also  a  synonym); _e_m_a_c_s is equivalent to _e_m_a_c_s_-_s_t_a_n_-
                     _d_a_r_d.
              --ll     List the names of all rreeaaddlliinnee functions.
              --pp     Display rreeaaddlliinnee function names and bindings  in  such  a
                     way that they can be re-read.
              --PP     List current rreeaaddlliinnee function names and bindings.
              --ss     Display  rreeaaddlliinnee  key  sequences bound to macros and the
                     strings they output in such a way that they  can  be  re-
                     read.
              --SS     Display  rreeaaddlliinnee  key  sequences bound to macros and the
                     strings they output.
              --vv     Display rreeaaddlliinnee variable names and values in such a  way
                     that they can be re-read.
              --VV     List current rreeaaddlliinnee variable names and values.
              --ff _f_i_l_e_n_a_m_e
                     Read key bindings from _f_i_l_e_n_a_m_e.
              --qq _f_u_n_c_t_i_o_n
                     Query about which keys invoke the named _f_u_n_c_t_i_o_n.
              --uu _f_u_n_c_t_i_o_n
                     Unbind all keys bound to the named _f_u_n_c_t_i_o_n.
              --rr _k_e_y_s_e_q
                     Remove any current binding for _k_e_y_s_e_q.
              --xx _k_e_y_s_e_q::_s_h_e_l_l_-_c_o_m_m_a_n_d
                     Cause  _s_h_e_l_l_-_c_o_m_m_a_n_d  to  be  executed whenever _k_e_y_s_e_q is
                     entered.  When _s_h_e_l_l_-_c_o_m_m_a_n_d is executed, the shell  sets
                     the  RREEAADDLLIINNEE__LLIINNEE  variable to the contents of the rreeaadd--
                     lliinnee line buffer and the RREEAADDLLIINNEE__PPOOIINNTT variable  to  the
                     current location of the insertion point.  If the executed
                     command changes  the  value  of  RREEAADDLLIINNEE__LLIINNEE  or  RREEAADD--
                     LLIINNEE__PPOOIINNTT,  those  new  values  will be reflected in the
                     editing state.
              --XX     List all key sequences bound to shell  commands  and  the
                     associated  commands  in  a  format that can be reused as
                     input.

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

       bbrreeaakk [_n]
              Exit  from  within a ffoorr, wwhhiillee, uunnttiill, or sseelleecctt loop.  If _n is
              specified, break _n levels.  _n must be >= 1.   If  _n  is  greater
              than  the  number  of  enclosing  loops, all enclosing loops are
              exited.  The return value is 0 unless _n is not greater  than  or
              equal to 1.

       bbuuiillttiinn _s_h_e_l_l_-_b_u_i_l_t_i_n [_a_r_g_u_m_e_n_t_s]
              Execute  the  specified shell builtin, passing it _a_r_g_u_m_e_n_t_s, and
              return its exit status.  This is useful when defining a function
              whose  name  is the same as a shell builtin, retaining the func-
              tionality of the builtin within the function.  The ccdd builtin is
              commonly  redefined  this  way.   The  return status is false if
              _s_h_e_l_l_-_b_u_i_l_t_i_n is not a shell builtin command.

       ccaalllleerr [_e_x_p_r]
              Returns the context of any active subroutine call (a shell func-
              tion or a script executed with the .. or ssoouurrccee builtins).  With-
              out _e_x_p_r, ccaalllleerr displays the line number and source filename of
              the  current subroutine call.  If a non-negative integer is sup-
              plied as _e_x_p_r, ccaalllleerr displays the line number, subroutine name,
              and  source  file  corresponding to that position in the current
              execution call stack.  This extra information may be  used,  for
              example,  to print a stack trace.  The current frame is frame 0.
              The return value is 0 unless the shell is not executing  a  sub-
              routine  call or _e_x_p_r does not correspond to a valid position in
              the call stack.

       ccdd [--LL|[--PP [--ee]] [-@]] [_d_i_r]
              Change the current directory to _d_i_r.  if _d_i_r  is  not  supplied,
              the  value of the HHOOMMEE shell variable is the default.  Any addi-
              tional arguments following _d_i_r are ignored.  The variable CCDDPPAATTHH
              defines  the  search path for the directory containing _d_i_r: each
              directory name in  CCDDPPAATTHH  is  searched  for  _d_i_r.   Alternative
              directory  names in CCDDPPAATTHH are separated by a colon (:).  A null
              directory name in CCDDPPAATTHH is the same as the  current  directory,
              i.e., ``..''.  If _d_i_r begins with a slash (/), then CCDDPPAATTHH is not
              used.  The --PP option causes ccdd to  use  the  physical  directory
              structure  by  resolving symbolic links while traversing _d_i_r and
              before processing instances of _._. in _d_i_r (see also the --PP option
              to the sseett builtin command); the --LL option forces symbolic links
              to be followed by resolving the link after processing  instances
              of _._. in _d_i_r.  If _._. appears in _d_i_r, it is processed by removing
              the immediately previous pathname component from _d_i_r, back to  a
              slash  or  the  beginning  of _d_i_r.  If the --ee option is supplied
              with --PP, and the current working directory  cannot  be  success-
              fully  determined  after  a successful directory change, ccdd will
              return an unsuccessful status.  On systems that support it,  the
              --@@  option  presents  the  extended attributes associated with a
              file as a directory.  An argument of -- is converted  to  $$OOLLDDPPWWDD
              before the directory change is attempted.  If a non-empty direc-
              tory name from CCDDPPAATTHH is used, or if -- is  the  first  argument,
              and the directory change is successful, the absolute pathname of
              the new working directory is written  to  the  standard  output.
              The  return  value  is  true  if  the directory was successfully
              changed; false otherwise.

       ccoommmmaanndd [--ppVVvv] _c_o_m_m_a_n_d [_a_r_g ...]
              Run _c_o_m_m_a_n_d with _a_r_g_s  suppressing  the  normal  shell  function
              lookup.  Only builtin commands or commands found in the PPAATTHH are
              executed.  If the --pp option is given, the search for _c_o_m_m_a_n_d  is
              performed  using  a default value for PPAATTHH that is guaranteed to
              find all of the standard utilities.  If  either  the  --VV  or  --vv
              option is supplied, a description of _c_o_m_m_a_n_d is printed.  The --vv
              option causes a single word indicating the command  or  filename
              used to invoke _c_o_m_m_a_n_d to be displayed; the --VV option produces a
              more verbose description.  If the --VV or --vv option  is  supplied,
              the  exit  status  is  0 if _c_o_m_m_a_n_d was found, and 1 if not.  If
              neither option is supplied and an error occurred or _c_o_m_m_a_n_d can-
              not  be found, the exit status is 127.  Otherwise, the exit sta-
              tus of the ccoommmmaanndd builtin is the exit status of _c_o_m_m_a_n_d.

       ccoommppggeenn [_o_p_t_i_o_n] [_w_o_r_d]
              Generate possible completion matches for _w_o_r_d according  to  the
              _o_p_t_i_o_ns,  which  may  be  any  option  accepted  by the ccoommpplleettee
              builtin with the exception of --pp and --rr, and write  the  matches
              to  the  standard  output.  When using the --FF or --CC options, the
              various shell  variables  set  by  the  programmable  completion
              facilities, while available, will not have useful values.

              The matches will be generated in the same way as if the program-
              mable completion code had generated them directly from a comple-
              tion  specification  with the same flags.  If _w_o_r_d is specified,
              only those completions matching _w_o_r_d will be displayed.

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

       ccoommpplleettee  [--aabbccddeeffggjjkkssuuvv] [--oo _c_o_m_p_-_o_p_t_i_o_n] [--DDEEII] [--AA _a_c_t_i_o_n] [--GG _g_l_o_b_-
       _p_a_t] [--WW _w_o_r_d_l_i_s_t] [--FF _f_u_n_c_t_i_o_n] [--CC _c_o_m_m_a_n_d]
              [--XX _f_i_l_t_e_r_p_a_t] [--PP _p_r_e_f_i_x] [--SS _s_u_f_f_i_x] _n_a_m_e [_n_a_m_e _._._.]
       ccoommpplleettee --pprr [--DDEEII] [_n_a_m_e ...]
              Specify how arguments to each _n_a_m_e should be completed.  If  the
              --pp  option  is supplied, or if no options are supplied, existing
              completion specifications are printed in a way that allows  them
              to be reused as input.  The --rr option removes a completion spec-
              ification for each _n_a_m_e, or, if no _n_a_m_es are supplied, all  com-
              pletion specifications.  The --DD option indicates that other sup-
              plied options and actions should apply to the  ``default''  com-
              mand  completion; that is, completion attempted on a command for
              which no completion has previously been defined.  The --EE  option
              indicates  that  other supplied options and actions should apply
              to ``empty'' command completion; that is,  completion  attempted
              on  a  blank  line.  The --II option indicates that other supplied
              options and actions should apply to  completion  on  the  inital
              non-assignment  word  on  the line, or after a command delimiter
              such as ;; or ||, which is usually command  name  completion.   If
              multiple  options  are  supplied, the --DD option takes precedence
              over --EE, and both take precedence over --II.  If any of --DD, --EE, or
              --II  are  supplied,  any  other _n_a_m_e arguments are ignored; these
              completions only apply to the case specified by the option.

              The process of applying  these  completion  specifications  when
              word  completion  is attempted is described above under PPrrooggrraamm--
              mmaabbllee CCoommpplleettiioonn.

              Other options, if specified, have the following  meanings.   The
              arguments  to the --GG, --WW, and --XX options (and, if necessary, the
              --PP and --SS options) should be quoted to protect them from  expan-
              sion before the ccoommpplleettee builtin is invoked.
              --oo _c_o_m_p_-_o_p_t_i_o_n
                      The  _c_o_m_p_-_o_p_t_i_o_n  controls  several aspects of the comp-
                      spec's behavior beyond the simple generation of  comple-
                      tions.  _c_o_m_p_-_o_p_t_i_o_n may be one of:
                      bbaasshhddeeffaauulltt
                              Perform the rest of the default bbaasshh completions
                              if the compspec generates no matches.
                      ddeeffaauulltt Use readline's default  filename  completion  if
                              the compspec generates no matches.
                      ddiirrnnaammeess
                              Perform  directory  name completion if the comp-
                              spec generates no matches.
                      ffiilleennaammeess
                              Tell readline that the compspec generates  file-
                              names,  so  it can perform any filename-specific
                              processing (like adding  a  slash  to  directory
                              names,  quoting special characters, or suppress-
                              ing trailing spaces).  Intended to be used  with
                              shell functions.
                      nnooqquuoottee Tell  readline  not to quote the completed words
                              if they are filenames (quoting filenames is  the
                              default).
                      nnoossoorrtt  Tell  readline  not to sort the list of possible
                              completions alphabetically.
                      nnoossppaaccee Tell  readline  not  to  append  a  space   (the
                              default)  to  words  completed at the end of the
                              line.
                      pplluussddiirrss
                              After any matches defined by  the  compspec  are
                              generated,    directory   name   completion   is
                              attempted and  any  matches  are  added  to  the
                              results of the other actions.
              --AA _a_c_t_i_o_n
                      The  _a_c_t_i_o_n  may  be  one of the following to generate a
                      list of possible completions:
                      aalliiaass   Alias names.  May also be specified as --aa.
                      aarrrraayyvvaarr
                              Array variable names.
                      bbiinnddiinngg RReeaaddlliinnee key binding names.
                      bbuuiillttiinn Names of shell builtin commands.   May  also  be
                              specified as --bb.
                      ccoommmmaanndd Command names.  May also be specified as --cc.
                      ddiirreeccttoorryy
                              Directory names.  May also be specified as --dd.
                      ddiissaabblleedd
                              Names of disabled shell builtins.
                      eennaabblleedd Names of enabled shell builtins.
                      eexxppoorrtt  Names  of exported shell variables.  May also be
                              specified as --ee.
                      ffiillee    File names.  May also be specified as --ff.
                      ffuunnccttiioonn
                              Names of shell functions.
                      ggrroouupp   Group names.  May also be specified as --gg.
                      hheellppttooppiicc
                              Help topics as accepted by the hheellpp builtin.
                      hhoossttnnaammee
                              Hostnames, as taken from the file  specified  by
                              the HHOOSSTTFFIILLEE shell variable.
                      jjoobb     Job  names,  if job control is active.  May also
                              be specified as --jj.
                      kkeeyywwoorrdd Shell reserved words.  May also be specified  as
                              --kk.
                      rruunnnniinngg Names of running jobs, if job control is active.
                      sseerrvviiccee Service names.  May also be specified as --ss.
                      sseettoopptt  Valid  arguments  for  the  --oo option to the sseett
                              builtin.
                      sshhoopptt   Shell option names  as  accepted  by  the  sshhoopptt
                              builtin.
                      ssiiggnnaall  Signal names.
                      ssttooppppeedd Names of stopped jobs, if job control is active.
                      uusseerr    User names.  May also be specified as --uu.
                      vvaarriiaabbllee
                              Names of all shell variables.  May also be spec-
                              ified as --vv.
              --CC _c_o_m_m_a_n_d
                      _c_o_m_m_a_n_d is executed in a subshell environment,  and  its
                      output is used as the possible completions.
              --FF _f_u_n_c_t_i_o_n
                      The  shell  function _f_u_n_c_t_i_o_n is executed in the current
                      shell environment.  When the function is  executed,  the
                      first  argument  ($$11)  is  the name of the command whose
                      arguments are being completed, the second argument  ($$22)
                      is the word being completed, and the third argument ($$33)
                      is the word preceding the word being  completed  on  the
                      current  command  line.   When it finishes, the possible
                      completions are retrieved from the value of the  CCOOMMPPRREE--
                      PPLLYY array variable.
              --GG _g_l_o_b_p_a_t
                      The  pathname  expansion  pattern _g_l_o_b_p_a_t is expanded to
                      generate the possible completions.
              --PP _p_r_e_f_i_x
                      _p_r_e_f_i_x is added at the beginning of each  possible  com-
                      pletion after all other options have been applied.
              --SS _s_u_f_f_i_x
                      _s_u_f_f_i_x is appended to each possible completion after all
                      other options have been applied.
              --WW _w_o_r_d_l_i_s_t
                      The _w_o_r_d_l_i_s_t is split using the characters  in  the  IIFFSS
                      special  variable as delimiters, and each resultant word
                      is expanded.  Shell quoting is honored within  _w_o_r_d_l_i_s_t,
                      in order to provide a mechanism for the words to contain
                      shell metacharacters or characters in the value of  IIFFSS.
                      The  possible  completions are the members of the resul-
                      tant list which match the word being completed.
              --XX _f_i_l_t_e_r_p_a_t
                      _f_i_l_t_e_r_p_a_t is a pattern as used for  pathname  expansion.
                      It is applied to the list of possible completions gener-
                      ated by the preceding options and  arguments,  and  each
                      completion  matching _f_i_l_t_e_r_p_a_t is removed from the list.
                      A leading !! in _f_i_l_t_e_r_p_a_t negates the  pattern;  in  this
                      case, any completion not matching _f_i_l_t_e_r_p_a_t is removed.

              The  return  value is true unless an invalid option is supplied,
              an option other than --pp or --rr is supplied without a  _n_a_m_e  argu-
              ment,  an  attempt  is made to remove a completion specification
              for a _n_a_m_e for which no specification exists, or an error occurs
              adding a completion specification.

       ccoommppoopptt [--oo _o_p_t_i_o_n] [--DDEEII] [++oo _o_p_t_i_o_n] [_n_a_m_e]
              Modify  completion  options  for  each  _n_a_m_e  according  to  the
              _o_p_t_i_o_ns, or for the currently-executing completion if  no  _n_a_m_es
              are  supplied.   If no _o_p_t_i_o_ns are given, display the completion
              options for each _n_a_m_e or the current completion.   The  possible
              values  of  _o_p_t_i_o_n  are  those  valid  for  the ccoommpplleettee builtin
              described above.  The --DD option indicates  that  other  supplied
              options should apply to the ``default'' command completion; that
              is, completion attempted on a command for  which  no  completion
              has previously been defined.  The --EE option indicates that other
              supplied options should apply to ``empty''  command  completion;
              that  is,  completion  attempted on a blank line.  The --II option
              indicates that other supplied options should apply to completion
              on  the  inital non-assignment word on the line, or after a com-
              mand delimiter such as ;; or ||, which  is  usually  command  name
              completion.

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

       ccoonnttiinnuuee [_n]
              Resume the next iteration of the enclosing ffoorr, wwhhiillee, uunnttiill, or
              sseelleecctt loop.  If _n is specified, resume  at  the  _nth  enclosing
              loop.   _n  must  be  >=  1.   If _n is greater than the number of
              enclosing loops, the  last  enclosing  loop  (the  ``top-level''
              loop) is resumed.  The return value is 0 unless _n is not greater
              than or equal to 1.

       ddeeccllaarree [--aaAAffFFggiillnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...]
       ttyyppeesseett [--aaAAffFFggiillnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...]
              Declare variables and/or give them attributes.  If no _n_a_m_es  are
              given  then display the values of variables.  The --pp option will
              display the attributes and values of each _n_a_m_e.  When --pp is used
              with  _n_a_m_e  arguments, additional options, other than --ff and --FF,
              are ignored.  When --pp is supplied  without  _n_a_m_e  arguments,  it
              will  display  the attributes and values of all variables having
              the attributes specified by the additional options.  If no other
              options   are   supplied  with  --pp,  ddeeccllaarree  will  display  the
              attributes and values of all shell  variables.   The  --ff  option
              will  restrict  the  display  to shell functions.  The --FF option
              inhibits the display of function definitions; only the  function
              name  and  attributes are printed.  If the eexxttddeebbuugg shell option
              is enabled using sshhoopptt, the source file  name  and  line  number
              where each _n_a_m_e is defined are displayed as well.  The --FF option
              implies --ff.  The --gg option forces variables  to  be  created  or
              modified at the global scope, even when ddeeccllaarree is executed in a
              shell function.  It is ignored in all other cases.  The  follow-
              ing options can be used to restrict output to variables with the
              specified attribute or to give variables attributes:
              --aa     Each _n_a_m_e  is  an  indexed  array  variable  (see  AArrrraayyss
                     above).
              --AA     Each  _n_a_m_e  is  an associative array variable (see AArrrraayyss
                     above).
              --ff     Use function names only.
              --ii     The variable is treated as an integer; arithmetic evalua-
                     tion  (see AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN above) is performed when
                     the variable is assigned a value.
              --ll     When the variable is assigned  a  value,  all  upper-case
                     characters  are  converted to lower-case.  The upper-case
                     attribute is disabled.
              --nn     Give each _n_a_m_e the _n_a_m_e_r_e_f attribute, making  it  a  name
                     reference  to  another  variable.  That other variable is
                     defined by the value of _n_a_m_e.   All  references,  assign-
                     ments,  and attribute modifications to _n_a_m_e, except those
                     using or changing the --nn attribute itself, are  performed
                     on  the variable referenced by _n_a_m_e's value.  The nameref
                     attribute cannot be applied to array variables.
              --rr     Make _n_a_m_es readonly.  These names cannot then be assigned
                     values by subsequent assignment statements or unset.
              --tt     Give  each  _n_a_m_e  the  _t_r_a_c_e attribute.  Traced functions
                     inherit the DDEEBBUUGG  and  RREETTUURRNN  traps  from  the  calling
                     shell.   The  trace  attribute has no special meaning for
                     variables.
              --uu     When the variable is assigned  a  value,  all  lower-case
                     characters  are  converted to upper-case.  The lower-case
                     attribute is disabled.
              --xx     Mark _n_a_m_es for export  to  subsequent  commands  via  the
                     environment.

              Using  `+'  instead of `-' turns off the attribute instead, with
              the exceptions that ++aa and ++AA may not be used to  destroy  array
              variables  and  ++rr will not remove the readonly attribute.  When
              used in a function, ddeeccllaarree and ttyyppeesseett make each _n_a_m_e local, as
              with  the llooccaall command, unless the --gg option is supplied.  If a
              variable name is followed by =_v_a_l_u_e, the value of  the  variable
              is  set  to _v_a_l_u_e.  When using --aa or --AA and the compound assign-
              ment syntax to create array variables, additional attributes  do
              not  take effect until subsequent assignments.  The return value
              is 0 unless an invalid option is encountered, an attempt is made
              to define a function using ``-f foo=bar'', an attempt is made to
              assign a value to a readonly variable, an  attempt  is  made  to
              assign  a  value to an array variable without using the compound
              assignment syntax (see AArrrraayyss above), one of the _n_a_m_e_s is not  a
              valid  shell variable name, an attempt is made to turn off read-
              only status for a readonly variable, an attempt is made to  turn
              off array status for an array variable, or an attempt is made to
              display a non-existent function with --ff.

       ddiirrss [[--ccllppvv]] [[++_n]] [[--_n]]
              Without options,  displays  the  list  of  currently  remembered
              directories.   The  default  display  is  on  a single line with
              directory names separated by spaces.  Directories are  added  to
              the  list  with  the  ppuusshhdd  command;  the  ppooppdd command removes
              entries from the list.  The  current  directory  is  always  the
              first directory in the stack.
              --cc     Clears  the  directory  stack  by  deleting  all  of  the
                     entries.
              --ll     Produces a listing  using  full  pathnames;  the  default
                     listing format uses a tilde to denote the home directory.
              --pp     Print the directory stack with one entry per line.
              --vv     Print  the  directory stack with one entry per line, pre-
                     fixing each entry with its index in the stack.
              ++_n     Displays the _nth entry counting from the left of the list
                     shown by ddiirrss when invoked without options, starting with
                     zero.
              --_n     Displays the _nth entry counting from  the  right  of  the
                     list shown by ddiirrss when invoked without options, starting
                     with zero.

              The return value is 0 unless an invalid option is supplied or  _n
              indexes beyond the end of the directory stack.

       ddiissoowwnn [--aarr] [--hh] [_j_o_b_s_p_e_c ... | _p_i_d ... ]
              Without  options,  remove  each _j_o_b_s_p_e_c from the table of active
              jobs.  If _j_o_b_s_p_e_c is not present, and neither the --aa nor the  --rr
              option  is  supplied, the _c_u_r_r_e_n_t _j_o_b is used.  If the --hh option
              is given, each _j_o_b_s_p_e_c is not removed from  the  table,  but  is
              marked  so  that  SSIIGGHHUUPP  is  not  sent  to the job if the shell
              receives a SSIIGGHHUUPP.  If no _j_o_b_s_p_e_c is  supplied,  the  --aa  option
              means  to  remove or mark all jobs; the --rr option without a _j_o_b_-
              _s_p_e_c argument restricts operation to running jobs.   The  return
              value is 0 unless a _j_o_b_s_p_e_c does not specify a valid job.

       eecchhoo [--nneeEE] [_a_r_g ...]
              Output  the  _a_r_gs,  separated  by spaces, followed by a newline.
              The return status is 0 unless a write error occurs.   If  --nn  is
              specified, the trailing newline is suppressed.  If the --ee option
              is given,  interpretation  of  the  following  backslash-escaped
              characters  is  enabled.  The --EE option disables the interpreta-
              tion of these escape characters, even on systems where they  are
              interpreted  by  default.  The xxppgg__eecchhoo shell option may be used
              to dynamically determine  whether  or  not  eecchhoo  expands  these
              escape  characters  by  default.   eecchhoo does not interpret ---- to
              mean the end of options.  eecchhoo interprets the  following  escape
              sequences:
              \\aa     alert (bell)
              \\bb     backspace
              \\cc     suppress further output
              \\ee
              \\EE     an escape character
              \\ff     form feed
              \\nn     new line
              \\rr     carriage return
              \\tt     horizontal tab
              \\vv     vertical tab
              \\\\     backslash
              \\00_n_n_n  the  eight-bit  character  whose value is the octal value
                     _n_n_n (zero to three octal digits)
              \\xx_H_H   the eight-bit character whose value  is  the  hexadecimal
                     value _H_H (one or two hex digits)
              \\uu_H_H_H_H the  Unicode (ISO/IEC 10646) character whose value is the
                     hexadecimal value _H_H_H_H (one to four hex digits)
              \\UU_H_H_H_H_H_H_H_H
                     the Unicode (ISO/IEC 10646) character whose value is  the
                     hexadecimal value _H_H_H_H_H_H_H_H (one to eight hex digits)

       eennaabbllee [--aa] [--ddnnppss] [--ff _f_i_l_e_n_a_m_e] [_n_a_m_e ...]
              Enable  and disable builtin shell commands.  Disabling a builtin
              allows a disk command which has the same name as a shell builtin
              to  be  executed without specifying a full pathname, even though
              the shell normally searches for builtins before  disk  commands.
              If  --nn  is  used,  each  _n_a_m_e  is disabled; otherwise, _n_a_m_e_s are
              enabled.  For example, to use the tteesstt binary found via the PPAATTHH
              instead  of  the  shell builtin version, run ``enable -n test''.
              The --ff option means to load the new builtin  command  _n_a_m_e  from
              shared object _f_i_l_e_n_a_m_e, on systems that support dynamic loading.
              The --dd option will delete a builtin previously loaded  with  --ff.
              If no _n_a_m_e arguments are given, or if the --pp option is supplied,
              a list of shell builtins is printed.  With no other option argu-
              ments,  the  list consists of all enabled shell builtins.  If --nn
              is supplied, only disabled builtins are printed.  If --aa is  sup-
              plied,  the  list printed includes all builtins, with an indica-
              tion of whether or not each is enabled.  If --ss is supplied,  the
              output  is restricted to the POSIX _s_p_e_c_i_a_l builtins.  The return
              value is 0 unless a _n_a_m_e is not a shell builtin or there  is  an
              error loading a new builtin from a shared object.

       eevvaall [_a_r_g ...]
              The  _a_r_gs  are read and concatenated together into a single com-
              mand.  This command is then read and executed by the shell,  and
              its  exit status is returned as the value of eevvaall.  If there are
              no _a_r_g_s, or only null arguments, eevvaall returns 0.

       eexxeecc [--ccll] [--aa _n_a_m_e] [_c_o_m_m_a_n_d [_a_r_g_u_m_e_n_t_s]]
              If _c_o_m_m_a_n_d is specified, it replaces the shell.  No new  process
              is  created.  The _a_r_g_u_m_e_n_t_s become the arguments to _c_o_m_m_a_n_d.  If
              the --ll option is supplied, the shell places a dash at the begin-
              ning  of  the  zeroth  argument passed to _c_o_m_m_a_n_d.  This is what
              _l_o_g_i_n(1) does.  The --cc option causes _c_o_m_m_a_n_d to be executed with
              an  empty environment.  If --aa is supplied, the shell passes _n_a_m_e
              as the zeroth argument to the executed command.  If _c_o_m_m_a_n_d can-
              not  be executed for some reason, a non-interactive shell exits,
              unless the eexxeeccffaaiill shell option is enabled.  In that  case,  it
              returns  failure.   An  interactive shell returns failure if the
              file cannot be executed.  A subshell  exits  unconditionally  if
              eexxeecc  fails.  If _c_o_m_m_a_n_d is not specified, any redirections take
              effect in the current shell, and the return  status  is  0.   If
              there is a redirection error, the return status is 1.

       eexxiitt [_n]
              Cause  the  shell  to exit with a status of _n.  If _n is omitted,
              the exit status is that of the last command executed.  A trap on
              EEXXIITT is executed before the shell terminates.

       eexxppoorrtt [--ffnn] [_n_a_m_e[=_w_o_r_d]] ...
       eexxppoorrtt --pp
              The  supplied _n_a_m_e_s are marked for automatic export to the envi-
              ronment of subsequently executed commands.  If the --ff option  is
              given,  the _n_a_m_e_s refer to functions.  If no _n_a_m_e_s are given, or
              if the --pp option is supplied, a list of names  of  all  exported
              variables  is printed.  The --nn option causes the export property
              to be removed from each _n_a_m_e.  If a variable name is followed by
              =_w_o_r_d, the value of the variable is set to _w_o_r_d.  eexxppoorrtt returns
              an exit status of 0 unless an invalid option is encountered, one
              of  the  _n_a_m_e_s is not a valid shell variable name, or --ff is sup-
              plied with a _n_a_m_e that is not a function.

       ffcc [--ee _e_n_a_m_e] [--llnnrr] [_f_i_r_s_t] [_l_a_s_t]
       ffcc --ss [_p_a_t=_r_e_p] [_c_m_d]
              The first form selects a range of commands from  _f_i_r_s_t  to  _l_a_s_t
              from  the  history  list  and  displays or edits and re-executes
              them.  _F_i_r_s_t and _l_a_s_t may be specified as a  string  (to  locate
              the  last command beginning with that string) or as a number (an
              index into the history list, where a negative number is used  as
              an  offset  from  the  current  command number).  If _l_a_s_t is not
              specified, it is set to the current command for listing (so that
              ``fc  -l  -10'' prints the last 10 commands) and to _f_i_r_s_t other-
              wise.  If _f_i_r_s_t is not specified, it is set to the previous com-
              mand for editing and -16 for listing.

              The  --nn option suppresses the command numbers when listing.  The
              --rr option reverses the order of the commands.  If the --ll  option
              is  given,  the  commands are listed on standard output.  Other-
              wise, the editor given by _e_n_a_m_e is invoked on a file  containing
              those  commands.  If _e_n_a_m_e is not given, the value of the FFCCEEDDIITT
              variable is used, and the value of EEDDIITTOORR if FFCCEEDDIITT is not  set.
              If  neither  variable  is set, _v_i is used.  When editing is com-
              plete, the edited commands are echoed and executed.

              In the second form, _c_o_m_m_a_n_d is re-executed after  each  instance
              of  _p_a_t  is replaced by _r_e_p.  _C_o_m_m_a_n_d is interpreted the same as
              _f_i_r_s_t above.  A useful alias to use with this is ``r="fc  -s"'',
              so  that  typing  ``r  cc'' runs the last command beginning with
              ``cc'' and typing ``r'' re-executes the last command.

              If the first form is used, the  return  value  is  0  unless  an
              invalid  option  is encountered or _f_i_r_s_t or _l_a_s_t specify history
              lines out of range.  If the --ee option is  supplied,  the  return
              value is the value of the last command executed or failure if an
              error occurs with the temporary file of commands.  If the second
              form  is  used, the return status is that of the command re-exe-
              cuted, unless _c_m_d does not specify  a  valid  history  line,  in
              which case ffcc returns failure.

       ffgg [_j_o_b_s_p_e_c]
              Resume  _j_o_b_s_p_e_c  in the foreground, and make it the current job.
              If _j_o_b_s_p_e_c is not present, the shell's notion of the _c_u_r_r_e_n_t _j_o_b
              is  used.   The  return value is that of the command placed into
              the foreground, or failure if run when job control  is  disabled
              or, when run with job control enabled, if _j_o_b_s_p_e_c does not spec-
              ify a valid job or _j_o_b_s_p_e_c specifies  a  job  that  was  started
              without job control.

       ggeettooppttss _o_p_t_s_t_r_i_n_g _n_a_m_e [_a_r_g_s]
              ggeettooppttss  is used by shell procedures to parse positional parame-
              ters.  _o_p_t_s_t_r_i_n_g contains the option  characters  to  be  recog-
              nized;  if  a  character  is  followed by a colon, the option is
              expected to have an argument, which should be separated from  it
              by  white space.  The colon and question mark characters may not
              be used as option characters.  Each time it is invoked,  ggeettooppttss
              places  the next option in the shell variable _n_a_m_e, initializing
              _n_a_m_e if it does not exist, and the index of the next argument to
              be processed into the variable OOPPTTIINNDD.  OOPPTTIINNDD is initialized to
              1 each time the shell or a shell script  is  invoked.   When  an
              option  requires  an argument, ggeettooppttss places that argument into
              the variable OOPPTTAARRGG.  The shell does not reset OOPPTTIINNDD  automati-
              cally;  it  must  be  manually  reset  between multiple calls to
              ggeettooppttss within the same shell invocation if a new set of parame-
              ters is to be used.

              When  the  end  of  options is encountered, ggeettooppttss exits with a
              return value greater than zero.  OOPPTTIINNDD is set to the  index  of
              the first non-option argument, and _n_a_m_e is set to ?.

              ggeettooppttss  normally  parses the positional parameters, but if more
              arguments are given in _a_r_g_s, ggeettooppttss parses those instead.

              ggeettooppttss can report errors in two ways.  If the  first  character
              of  _o_p_t_s_t_r_i_n_g  is  a  colon, _s_i_l_e_n_t error reporting is used.  In
              normal operation, diagnostic messages are printed  when  invalid
              options  or  missing  option  arguments are encountered.  If the
              variable OOPPTTEERRRR is set to 0, no  error  messages  will  be  dis-
              played, even if the first character of _o_p_t_s_t_r_i_n_g is not a colon.

              If an invalid option is seen, ggeettooppttss places ? into _n_a_m_e and, if
              not silent, prints an  error  message  and  unsets  OOPPTTAARRGG.   If
              ggeettooppttss  is  silent,  the  option  character  found is placed in
              OOPPTTAARRGG and no diagnostic message is printed.

              If a required argument is not found, and ggeettooppttss is not  silent,
              a  question  mark  (??) is placed in _n_a_m_e, OOPPTTAARRGG is unset, and a
              diagnostic message is printed.  If ggeettooppttss  is  silent,  then  a
              colon  (::)  is  placed  in  _n_a_m_e and OOPPTTAARRGG is set to the option
              character found.

              ggeettooppttss returns true if an option, specified or unspecified,  is
              found.  It returns false if the end of options is encountered or
              an error occurs.

       hhaasshh [--llrr] [--pp _f_i_l_e_n_a_m_e] [--ddtt] [_n_a_m_e]
              Each time hhaasshh is invoked, the full pathname of the command _n_a_m_e
              is  determined  by searching the directories in $$PPAATTHH and remem-
              bered.  Any previously-remembered pathname is discarded.  If the
              --pp option is supplied, no path search is performed, and _f_i_l_e_n_a_m_e
              is used as the full filename of  the  command.   The  --rr  option
              causes  the  shell  to  forget all remembered locations.  The --dd
              option causes the shell to forget  the  remembered  location  of
              each  _n_a_m_e.   If the --tt option is supplied, the full pathname to
              which each _n_a_m_e corresponds is printed.  If multiple _n_a_m_e  argu-
              ments  are  supplied  with  --tt,  the  _n_a_m_e is printed before the
              hashed full pathname.  The --ll option causes output  to  be  dis-
              played in a format that may be reused as input.  If no arguments
              are given, or if only --ll is supplied, information  about  remem-
              bered  commands  is printed.  The return status is true unless a
              _n_a_m_e is not found or an invalid option is supplied.

       hheellpp [--ddmmss] [_p_a_t_t_e_r_n]
              Display helpful information about builtin commands.  If  _p_a_t_t_e_r_n
              is  specified, hheellpp gives detailed help on all commands matching
              _p_a_t_t_e_r_n; otherwise help for all the builtins and  shell  control
              structures is printed.
              --dd     Display a short description of each _p_a_t_t_e_r_n
              --mm     Display the description of each _p_a_t_t_e_r_n in a manpage-like
                     format
              --ss     Display only a short usage synopsis for each _p_a_t_t_e_r_n

              The return status is 0 unless no command matches _p_a_t_t_e_r_n.

       hhiissttoorryy [[_n]]
       hhiissttoorryy --cc
       hhiissttoorryy --dd _o_f_f_s_e_t
       hhiissttoorryy --dd _s_t_a_r_t-_e_n_d
       hhiissttoorryy --aannrrww [_f_i_l_e_n_a_m_e]
       hhiissttoorryy --pp _a_r_g [_a_r_g _._._.]
       hhiissttoorryy --ss _a_r_g [_a_r_g _._._.]
              With no options, display the command history list with line num-
              bers.  Lines listed with a ** have been modified.  An argument of
              _n lists only the last _n lines.  If the shell variable  HHIISSTTTTIIMMEE--
              FFOORRMMAATT  is  set  and not null, it is used as a format string for
              _s_t_r_f_t_i_m_e(3) to display the time stamp associated with each  dis-
              played  history  entry.  No intervening blank is printed between
              the formatted time stamp and the history line.  If  _f_i_l_e_n_a_m_e  is
              supplied,  it  is  used as the name of the history file; if not,
              the value of HHIISSTTFFIILLEE is used.  Options, if supplied,  have  the
              following meanings:
              --cc     Clear the history list by deleting all the entries.
              --dd _o_f_f_s_e_t
                     Delete  the  history entry at position _o_f_f_s_e_t.  If _o_f_f_s_e_t
                     is negative, it is interpreted as relative to one greater
                     than the last history position, so negative indices count
                     back from the end of the history,  and  an  index  of  -1
                     refers to the current hhiissttoorryy --dd command.
              --dd _s_t_a_r_t-_e_n_d
                     Delete  the  history  entries between positions _s_t_a_r_t and
                     _e_n_d, inclusive.  Positive and negative values  for  _s_t_a_r_t
                     and _e_n_d are interpreted as described above.
              --aa     Append  the  ``new''  history  lines to the history file.
                     These are history lines entered since  the  beginning  of
                     the current bbaasshh session, but not already appended to the
                     history file.
              --nn     Read the history lines not already read from the  history
                     file  into  the  current  history  list.  These are lines
                     appended to the history file since the beginning  of  the
                     current bbaasshh session.
              --rr     Read  the contents of the history file and append them to
                     the current history list.
              --ww     Write the current history list to the history file, over-
                     writing the history file's contents.
              --pp     Perform  history  substitution  on the following _a_r_g_s and
                     display the result on  the  standard  output.   Does  not
                     store  the results in the history list.  Each _a_r_g must be
                     quoted to disable normal history expansion.
              --ss     Store the _a_r_g_s in the history list  as  a  single  entry.
                     The  last  command  in the history list is removed before
                     the _a_r_g_s are added.

              If the HHIISSTTTTIIMMEEFFOORRMMAATT variable is set, the time  stamp  informa-
              tion  associated  with each history entry is written to the his-
              tory file, marked with the history comment character.  When  the
              history  file  is read, lines beginning with the history comment
              character followed immediately by a  digit  are  interpreted  as
              timestamps for the following history entry.  The return value is
              0 unless an invalid option is encountered, an error occurs while
              reading  or  writing the history file, an invalid _o_f_f_s_e_t is sup-
              plied as an argument to --dd, or the history expansion supplied as
              an argument to --pp fails.

       jjoobbss [--llnnpprrss] [ _j_o_b_s_p_e_c ... ]
       jjoobbss --xx _c_o_m_m_a_n_d [ _a_r_g_s ... ]
              The first form lists the active jobs.  The options have the fol-
              lowing meanings:
              --ll     List process IDs in addition to the normal information.
              --nn     Display information only about  jobs  that  have  changed
                     status since the user was last notified of their status.
              --pp     List  only  the  process  ID  of  the job's process group
                     leader.
              --rr     Display only running jobs.
              --ss     Display only stopped jobs.

              If _j_o_b_s_p_e_c is given, output is restricted to  information  about
              that  job.   The  return status is 0 unless an invalid option is
              encountered or an invalid _j_o_b_s_p_e_c is supplied.

              If the --xx option is supplied, jjoobbss replaces any _j_o_b_s_p_e_c found in
              _c_o_m_m_a_n_d  or  _a_r_g_s  with  the corresponding process group ID, and
              executes _c_o_m_m_a_n_d passing it _a_r_g_s, returning its exit status.

       kkiillll [--ss _s_i_g_s_p_e_c | --nn _s_i_g_n_u_m | --_s_i_g_s_p_e_c] [_p_i_d | _j_o_b_s_p_e_c] ...
       kkiillll --ll|--LL [_s_i_g_s_p_e_c | _e_x_i_t___s_t_a_t_u_s]
              Send the signal named by _s_i_g_s_p_e_c  or  _s_i_g_n_u_m  to  the  processes
              named  by  _p_i_d or _j_o_b_s_p_e_c.  _s_i_g_s_p_e_c is either a case-insensitive
              signal name such as SSIIGGKKIILLLL (with or without the SSIIGG prefix)  or
              a  signal  number; _s_i_g_n_u_m is a signal number.  If _s_i_g_s_p_e_c is not
              present, then SSIIGGTTEERRMM is assumed.  An argument of --ll  lists  the
              signal  names.   If any arguments are supplied when --ll is given,
              the names of the signals  corresponding  to  the  arguments  are
              listed, and the return status is 0.  The _e_x_i_t___s_t_a_t_u_s argument to
              --ll is a number specifying either a signal  number  or  the  exit
              status  of  a  process terminated by a signal.  The --LL option is
              equivalent to --ll.  kkiillll returns true if at least one signal  was
              successfully  sent,  or  false  if an error occurs or an invalid
              option is encountered.

       lleett _a_r_g [_a_r_g ...]
              Each _a_r_g is an arithmetic expression to be evaluated (see AARRIITTHH--
              MMEETTIICC  EEVVAALLUUAATTIIOONN  above).   If the last _a_r_g evaluates to 0, lleett
              returns 1; 0 is returned otherwise.

       llooccaall [_o_p_t_i_o_n] [_n_a_m_e[=_v_a_l_u_e] ... | - ]
              For each argument, a local variable named _n_a_m_e is  created,  and
              assigned  _v_a_l_u_e.   The _o_p_t_i_o_n can be any of the options accepted
              by ddeeccllaarree.  When llooccaall is used within a function, it causes the
              variable  _n_a_m_e  to have a visible scope restricted to that func-
              tion and its children.  If _n_a_m_e is -, the set of  shell  options
              is  made  local to the function in which llooccaall is invoked: shell
              options changed using the sseett builtin inside  the  function  are
              restored  to  their  original  values when the function returns.
              With no operands, llooccaall writes a list of local variables to  the
              standard  output.  It is an error to use llooccaall when not within a
              function.  The return status is 0 unless llooccaall is used outside a
              function,  an  invalid  _n_a_m_e  is supplied, or _n_a_m_e is a readonly
              variable.

       llooggoouutt Exit a login shell.

       mmaappffiillee [--dd _d_e_l_i_m] [--nn _c_o_u_n_t] [--OO _o_r_i_g_i_n] [--ss _c_o_u_n_t] [--tt] [--uu  _f_d]  [--CC
       _c_a_l_l_b_a_c_k] [--cc _q_u_a_n_t_u_m] [_a_r_r_a_y]
       rreeaaddaarrrraayy [--dd _d_e_l_i_m] [--nn _c_o_u_n_t] [--OO _o_r_i_g_i_n] [--ss _c_o_u_n_t] [--tt] [--uu _f_d] [--CC
       _c_a_l_l_b_a_c_k] [--cc _q_u_a_n_t_u_m] [_a_r_r_a_y]
              Read lines from the standard input into the indexed array  vari-
              able  _a_r_r_a_y, or from file descriptor _f_d if the --uu option is sup-
              plied.  The variable MMAAPPFFIILLEE is the default _a_r_r_a_y.  Options,  if
              supplied, have the following meanings:
              --dd     The  first  character  of _d_e_l_i_m is used to terminate each
                     input line, rather than newline.  If _d_e_l_i_m is  the  empty
                     string, mmaappffiillee will terminate a line when it reads a NUL
                     character.
              --nn     Copy at most _c_o_u_n_t lines.  If _c_o_u_n_t is 0, all  lines  are
                     copied.
              --OO     Begin  assigning  to  _a_r_r_a_y at index _o_r_i_g_i_n.  The default
                     index is 0.
              --ss     Discard the first _c_o_u_n_t lines read.
              --tt     Remove a trailing _d_e_l_i_m (default newline) from each  line
                     read.
              --uu     Read  lines  from file descriptor _f_d instead of the stan-
                     dard input.
              --CC     Evaluate _c_a_l_l_b_a_c_k each time _q_u_a_n_t_u_m lines are read.   The
                     --cc option specifies _q_u_a_n_t_u_m.
              --cc     Specify  the  number  of  lines read between each call to
                     _c_a_l_l_b_a_c_k.

              If --CC is specified without --cc,  the  default  quantum  is  5000.
              When _c_a_l_l_b_a_c_k is evaluated, it is supplied the index of the next
              array element to be assigned and the line to be assigned to that
              element  as  additional  arguments.  _c_a_l_l_b_a_c_k is evaluated after
              the line is read but before the array element is assigned.

              If not supplied with an  explicit  origin,  mmaappffiillee  will  clear
              _a_r_r_a_y before assigning to it.

              mmaappffiillee  returns successfully unless an invalid option or option
              argument is supplied, _a_r_r_a_y is invalid or  unassignable,  or  if
              _a_r_r_a_y is not an indexed array.

       ppooppdd [-nn] [+_n] [-_n]
              Removes  entries  from  the directory stack.  With no arguments,
              removes the top directory from the stack, and performs a  ccdd  to
              the new top directory.  Arguments, if supplied, have the follow-
              ing meanings:
              --nn     Suppresses the normal change of directory  when  removing
                     directories  from  the  stack,  so that only the stack is
                     manipulated.
              ++_n     Removes the _nth entry counting from the left of the  list
                     shown  by  ddiirrss, starting with zero.  For example: ``popd
                     +0'' removes the first directory, ``popd +1'' the second.
              --_n     Removes the _nth entry counting from the right of the list
                     shown  by  ddiirrss, starting with zero.  For example: ``popd
                     -0'' removes the last directory, ``popd -1'' the next  to
                     last.

              If  the ppooppdd command is successful, a ddiirrss is performed as well,
              and the return status is 0.  ppooppdd returns false  if  an  invalid
              option is encountered, the directory stack is empty, a non-exis-
              tent directory stack entry is specified, or the directory change
              fails.

       pprriinnttff [--vv _v_a_r] _f_o_r_m_a_t [_a_r_g_u_m_e_n_t_s]
              Write  the  formatted _a_r_g_u_m_e_n_t_s to the standard output under the
              control of the _f_o_r_m_a_t.  The --vv option causes the  output  to  be
              assigned  to  the  variable _v_a_r rather than being printed to the
              standard output.

              The _f_o_r_m_a_t is a character string which contains three  types  of
              objects:  plain  characters, which are simply copied to standard
              output, character escape  sequences,  which  are  converted  and
              copied  to  the standard output, and format specifications, each
              of which causes printing of the next  successive  _a_r_g_u_m_e_n_t.   In
              addition to the standard _p_r_i_n_t_f(1) format specifications, pprriinnttff
              interprets the following extensions:
              %%bb     causes pprriinnttff to expand backslash escape sequences in the
                     corresponding _a_r_g_u_m_e_n_t in the same way as eecchhoo --ee.
              %%qq     causes  pprriinnttff  to output the corresponding _a_r_g_u_m_e_n_t in a
                     format that can be reused as shell input.
              %%((_d_a_t_e_f_m_t))TT
                     causes pprriinnttff to output the  date-time  string  resulting
                     from  using  _d_a_t_e_f_m_t  as a format string for _s_t_r_f_t_i_m_e(3).
                     The corresponding _a_r_g_u_m_e_n_t is an integer representing the
                     number  of seconds since the epoch.  Two special argument
                     values may be used: -1 represents the current  time,  and
                     -2  represents  the  time  the  shell was invoked.  If no
                     argument is specified, conversion behaves as  if  -1  had
                     been  given.   This  is  an exception to the usual pprriinnttff
                     behavior.

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

              The  _f_o_r_m_a_t  is  reused as necessary to consume all of the _a_r_g_u_-
              _m_e_n_t_s.  If the _f_o_r_m_a_t requires more _a_r_g_u_m_e_n_t_s than are supplied,
              the  extra  format  specifications  behave as if a zero value or
              null string, as appropriate,  had  been  supplied.   The  return
              value is zero on success, non-zero on failure.

       ppuusshhdd [--nn] [+_n] [-_n]
       ppuusshhdd [--nn] [_d_i_r]
              Adds  a  directory to the top of the directory stack, or rotates
              the stack, making the new top of the stack the  current  working
              directory.   With  no  arguments,  ppuusshhdd  exchanges  the top two
              directories and returns 0, unless the directory stack is  empty.
              Arguments, if supplied, have the following meanings:
              --nn     Suppresses  the  normal change of directory when rotating
                     or adding directories to the  stack,  so  that  only  the
                     stack is manipulated.
              ++_n     Rotates  the  stack  so  that the _nth directory (counting
                     from the left of the list shown by  ddiirrss,  starting  with
                     zero) is at the top.
              --_n     Rotates  the  stack  so  that the _nth directory (counting
                     from the right of the list shown by ddiirrss,  starting  with
                     zero) is at the top.
              _d_i_r    Adds _d_i_r to the directory stack at the top, making it the
                     new current working directory as if it had been  supplied
                     as the argument to the ccdd builtin.

              If the ppuusshhdd command is successful, a ddiirrss is performed as well.
              If the first form is used, ppuusshhdd returns 0 unless the cd to  _d_i_r
              fails.   With the second form, ppuusshhdd returns 0 unless the direc-
              tory stack is empty, a non-existent directory stack  element  is
              specified,  or the directory change to the specified new current
              directory fails.

       ppwwdd [--LLPP]
              Print the absolute pathname of the  current  working  directory.
              The pathname printed contains no symbolic links if the --PP option
              is supplied or the --oo pphhyyssiiccaall option to the sseett builtin command
              is  enabled.  If the --LL option is used, the pathname printed may
              contain symbolic links.  The return status is 0 unless an  error
              occurs  while  reading  the  name of the current directory or an
              invalid option is supplied.

       rreeaadd [--eerrss] [--aa _a_n_a_m_e] [--dd _d_e_l_i_m] [--ii _t_e_x_t] [--nn _n_c_h_a_r_s] [--NN _n_c_h_a_r_s] [--pp
       _p_r_o_m_p_t] [--tt _t_i_m_e_o_u_t] [--uu _f_d] [_n_a_m_e ...]
              One  line  is  read  from  the  standard input, or from the file
              descriptor _f_d supplied as an argument to the  --uu  option,  split
              into  words  as  described  above  under WWoorrdd SSpplliittttiinngg, and the
              first word is assigned to the first _n_a_m_e, the second word to the
              second _n_a_m_e, and so on.  If there are more words than names, the
              remaining words and their intervening delimiters are assigned to
              the  last  _n_a_m_e.   If  there are fewer words read from the input
              stream than names, the remaining names are assigned  empty  val-
              ues.   The  characters  in  IIFFSS  are used to split the line into
              words  using  the  same  rules  the  shell  uses  for  expansion
              (described above under WWoorrdd SSpplliittttiinngg).  The backslash character
              (\\) may be used to remove any special meaning for the next char-
              acter  read  and  for  line continuation.  Options, if supplied,
              have the following meanings:
              --aa _a_n_a_m_e
                     The words are assigned to sequential indices of the array
                     variable _a_n_a_m_e, starting at 0.  _a_n_a_m_e is unset before any
                     new  values  are  assigned.   Other  _n_a_m_e  arguments  are
                     ignored.
              --dd _d_e_l_i_m
                     The  first  character  of  _d_e_l_i_m is used to terminate the
                     input line, rather than newline.  If _d_e_l_i_m is  the  empty
                     string,  rreeaadd  will  terminate a line when it reads a NUL
                     character.
              --ee     If the standard input is coming from a terminal, rreeaaddlliinnee
                     (see  RREEAADDLLIINNEE  above) is used to obtain the line.  Read-
                     line uses the current (or default, if  line  editing  was
                     not  previously  active) editing settings, but uses Read-
                     line's default filename completion.
              --ii _t_e_x_t
                     If rreeaaddlliinnee is being used  to  read  the  line,  _t_e_x_t  is
                     placed into the editing buffer before editing begins.
              --nn _n_c_h_a_r_s
                     rreeaadd  returns after reading _n_c_h_a_r_s characters rather than
                     waiting for a complete line of input, but honors a delim-
                     iter  if fewer than _n_c_h_a_r_s characters are read before the
                     delimiter.
              --NN _n_c_h_a_r_s
                     rreeaadd returns  after  reading  exactly  _n_c_h_a_r_s  characters
                     rather  than waiting for a complete line of input, unless
                     EOF is encountered or rreeaadd times out.  Delimiter  charac-
                     ters  encountered  in the input are not treated specially
                     and do not cause rreeaadd to return until  _n_c_h_a_r_s  characters
                     are  read.   The result is not split on the characters in
                     IIFFSS; the intent is that the variable is assigned  exactly
                     the characters read (with the exception of backslash; see
                     the --rr option below).
              --pp _p_r_o_m_p_t
                     Display _p_r_o_m_p_t on standard error, without a trailing new-
                     line, before attempting to read any input.  The prompt is
                     displayed only if input is coming from a terminal.
              --rr     Backslash does not act as an escape character.  The back-
                     slash  is considered to be part of the line.  In particu-
                     lar, a backslash-newline pair may not then be used  as  a
                     line continuation.
              --ss     Silent mode.  If input is coming from a terminal, charac-
                     ters are not echoed.
              --tt _t_i_m_e_o_u_t
                     Cause rreeaadd to time out and return failure if  a  complete
                     line  of  input  (or a specified number of characters) is
                     not read within _t_i_m_e_o_u_t seconds.  _t_i_m_e_o_u_t may be a  deci-
                     mal  number with a fractional portion following the deci-
                     mal point.  This option is  only  effective  if  rreeaadd  is
                     reading  input  from  a  terminal, pipe, or other special
                     file; it has no effect when reading from  regular  files.
                     If rreeaadd times out, rreeaadd saves any partial input read into
                     the specified variable  _n_a_m_e.   If  _t_i_m_e_o_u_t  is  0,  rreeaadd
                     returns  immediately,  without  trying  to read any data.
                     The exit status is 0 if input is available on the  speci-
                     fied  file descriptor, non-zero otherwise.  The exit sta-
                     tus is greater than 128 if the timeout is exceeded.
              --uu _f_d  Read input from file descriptor _f_d.

              If no _n_a_m_e_s are supplied, the line read is assigned to the vari-
              able  RREEPPLLYY.   The  exit  status  is zero, unless end-of-file is
              encountered, rreeaadd times out (in which case the status is greater
              than  128),  a variable assignment error (such as assigning to a
              readonly variable) occurs, or an invalid file descriptor is sup-
              plied as the argument to --uu.

       rreeaaddoonnllyy [--aaAAff] [--pp] [_n_a_m_e[=_w_o_r_d] ...]
              The  given  _n_a_m_e_s are marked readonly; the values of these _n_a_m_e_s
              may not be changed by subsequent assignment.  If the  --ff  option
              is  supplied,  the  functions  corresponding to the _n_a_m_e_s are so
              marked.  The  --aa  option  restricts  the  variables  to  indexed
              arrays;  the  --AA  option  restricts the variables to associative
              arrays.  If both options are supplied, --AA takes precedence.   If
              no  _n_a_m_e arguments are given, or if the --pp option is supplied, a
              list of all readonly names is printed.  The other options may be
              used  to  restrict the output to a subset of the set of readonly
              names.  The --pp option causes output to be displayed in a  format
              that  may be reused as input.  If a variable name is followed by
              =_w_o_r_d, the value of the variable is set  to  _w_o_r_d.   The  return
              status  is 0 unless an invalid option is encountered, one of the
              _n_a_m_e_s is not a valid shell variable name, or --ff is supplied with
              a _n_a_m_e that is not a function.

       rreettuurrnn [_n]
              Causes  a function to stop executing and return the value speci-
              fied by _n to its caller.  If _n is omitted, the return status  is
              that  of  the  last  command  executed in the function body.  If
              rreettuurrnn is executed by a trap handler, the last command  used  to
              determine  the  status  is  the last command executed before the
              trap handler.  If rreettuurrnn is executed during a  DDEEBBUUGG  trap,  the
              last  command  used  to determine the status is the last command
              executed by the trap handler  before  rreettuurrnn  was  invoked.   If
              rreettuurrnn  is  used  outside  a function, but during execution of a
              script by the ..  (ssoouurrccee) command, it causes the shell  to  stop
              executing  that script and return either _n or the exit status of
              the last command executed within the script as the  exit  status
              of  the script.  If _n is supplied, the return value is its least
              significant 8 bits.  The return status is non-zero if rreettuurrnn  is
              supplied  a  non-numeric argument, or is used outside a function
              and not during execution of a script by .. or ssoouurrccee.   Any  com-
              mand  associated  with the RREETTUURRNN trap is executed before execu-
              tion resumes after the function or script.

       sseett [----aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [--oo _o_p_t_i_o_n_-_n_a_m_e] [_a_r_g ...]
       sseett [++aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [++oo _o_p_t_i_o_n_-_n_a_m_e] [_a_r_g ...]
              Without options, the name and value of each shell  variable  are
              displayed in a format that can be reused as input for setting or
              resetting the currently-set variables.  Read-only variables can-
              not  be  reset.  In _p_o_s_i_x _m_o_d_e, only shell variables are listed.
              The output is sorted according  to  the  current  locale.   When
              options  are specified, they set or unset shell attributes.  Any
              arguments remaining after option processing are treated as  val-
              ues for the positional parameters and are assigned, in order, to
              $$11, $$22, ......  $$_n.  Options,  if  specified,  have  the  following
              meanings:
              --aa      Each variable or function that is created or modified is
                      given the export attribute and marked for export to  the
                      environment of subsequent commands.
              --bb      Report  the status of terminated background jobs immedi-
                      ately, rather than before the next primary prompt.  This
                      is effective only when job control is enabled.
              --ee      Exit  immediately  if a _p_i_p_e_l_i_n_e (which may consist of a
                      single _s_i_m_p_l_e _c_o_m_m_a_n_d), a _l_i_s_t, or  a  _c_o_m_p_o_u_n_d  _c_o_m_m_a_n_d
                      (see SSHHEELLLL GGRRAAMMMMAARR above), exits with a non-zero status.
                      The shell does not exit if the  command  that  fails  is
                      part  of  the command list immediately following a wwhhiillee
                      or uunnttiill keyword, part of the test following the  iiff  or
                      eelliiff  reserved  words, part of any command executed in a
                      &&&& or |||| list except the command following the final  &&&&
                      or ||||, any command in a pipeline but the last, or if the
                      command's return value is being inverted with !!.   If  a
                      compound  command  other  than a subshell returns a non-
                      zero status because a command failed while --ee was  being
                      ignored,  the  shell  does  not exit.  A trap on EERRRR, if
                      set, is executed before the shell  exits.   This  option
                      applies to the shell environment and each subshell envi-
                      ronment separately (see  CCOOMMMMAANNDD  EEXXEECCUUTTIIOONN  EENNVVIIRROONNMMEENNTT
                      above), and may cause subshells to exit before executing
                      all the commands in the subshell.

                      If a compound command or shell function  executes  in  a
                      context  where --ee is being ignored, none of the commands
                      executed within the compound command  or  function  body
                      will  be  affected  by the --ee setting, even if --ee is set
                      and a command returns a failure status.  If  a  compound
                      command  or  shell function sets --ee while executing in a
                      context where --ee is ignored, that setting will not  have
                      any  effect  until  the  compound command or the command
                      containing the function call completes.
              --ff      Disable pathname expansion.
              --hh      Remember the location of commands as they are looked  up
                      for execution.  This is enabled by default.
              --kk      All  arguments  in the form of assignment statements are
                      placed in the environment for a command, not just  those
                      that precede the command name.
              --mm      Monitor  mode.   Job control is enabled.  This option is
                      on by default for interactive  shells  on  systems  that
                      support  it  (see JJOOBB CCOONNTTRROOLL above).  All processes run
                      in a separate process group.  When a background job com-
                      pletes, the shell prints a line containing its exit sta-
                      tus.
              --nn      Read commands but do not execute them.  This may be used
                      to  check  a  shell  script  for syntax errors.  This is
                      ignored by interactive shells.
              --oo _o_p_t_i_o_n_-_n_a_m_e
                      The _o_p_t_i_o_n_-_n_a_m_e can be one of the following:
                      aalllleexxppoorrtt
                              Same as --aa.
                      bbrraacceeeexxppaanndd
                              Same as --BB.
                      eemmaaccss   Use an emacs-style command line  editing  inter-
                              face.  This is enabled by default when the shell
                              is interactive, unless the shell is started with
                              the  ----nnooeeddiittiinngg  option.  This also affects the
                              editing interface used for rreeaadd --ee.
                      eerrrreexxiitt Same as --ee.
                      eerrrrttrraaccee
                              Same as --EE.
                      ffuunnccttrraaccee
                              Same as --TT.
                      hhaasshhaallll Same as --hh.
                      hhiisstteexxppaanndd
                              Same as --HH.
                      hhiissttoorryy Enable command history, as described above under
                              HHIISSTTOORRYY.  This option is on by default in inter-
                              active shells.
                      iiggnnoorreeeeooff
                              The  effect  is  as   if   the   shell   command
                              ``IGNOREEOF=10''  had  been  executed (see SShheellll
                              VVaarriiaabblleess above).
                      kkeeyywwoorrdd Same as --kk.
                      mmoonniittoorr Same as --mm.
                      nnoocclloobbbbeerr
                              Same as --CC.
                      nnooeexxeecc  Same as --nn.
                      nnoogglloobb  Same as --ff.
                      nnoolloogg   Currently ignored.
                      nnoottiiffyy  Same as --bb.
                      nnoouunnsseett Same as --uu.
                      oonneeccmmdd  Same as --tt.
                      pphhyyssiiccaall
                              Same as --PP.
                      ppiippeeffaaiill
                              If set, the return value of a  pipeline  is  the
                              value  of  the  last (rightmost) command to exit
                              with a non-zero status, or zero if all  commands
                              in  the pipeline exit successfully.  This option
                              is disabled by default.
                      ppoossiixx   Change the behavior of bbaasshh  where  the  default
                              operation  differs  from  the  POSIX standard to
                              match the standard (_p_o_s_i_x _m_o_d_e).  See  SSEEEE  AALLSSOO
                              below for a reference to a document that details
                              how posix mode affects bash's behavior.
                      pprriivviilleeggeedd
                              Same as --pp.
                      vveerrbboossee Same as --vv.
                      vvii      Use a vi-style command line  editing  interface.
                              This also affects the editing interface used for
                              rreeaadd --ee.
                      xxttrraaccee  Same as --xx.
                      If --oo is supplied with no _o_p_t_i_o_n_-_n_a_m_e, the values of the
                      current  options are printed.  If ++oo is supplied with no
                      _o_p_t_i_o_n_-_n_a_m_e, a series of sseett commands  to  recreate  the
                      current  option  settings  is  displayed on the standard
                      output.
              --pp      Turn on _p_r_i_v_i_l_e_g_e_d mode.  In this  mode,  the  $$EENNVV  and
                      $$BBAASSHH__EENNVV  files  are not processed, shell functions are
                      not inherited from the environment, and  the  SSHHEELLLLOOPPTTSS,
                      BBAASSHHOOPPTTSS,  CCDDPPAATTHH,  and  GGLLOOBBIIGGNNOORREE  variables,  if they
                      appear in the environment, are ignored.  If the shell is
                      started  with the effective user (group) id not equal to
                      the real user (group) id, and the --pp option is not  sup-
                      plied, these actions are taken and the effective user id
                      is set to the real user id.  If the --pp  option  is  sup-
                      plied  at  startup,  the effective user id is not reset.
                      Turning this option off causes the  effective  user  and
                      group ids to be set to the real user and group ids.
              --tt      Exit after reading and executing one command.
              --uu      Treat unset variables and parameters other than the spe-
                      cial parameters "@" and "*" as an error when  performing
                      parameter  expansion.   If  expansion is attempted on an
                      unset variable or parameter, the shell prints  an  error
                      message,  and, if not interactive, exits with a non-zero
                      status.
              --vv      Print shell input lines as they are read.
              --xx      After expanding each _s_i_m_p_l_e _c_o_m_m_a_n_d, ffoorr  command,  ccaassee
                      command, sseelleecctt command, or arithmetic ffoorr command, dis-
                      play the expanded value of PPSS44, followed by the  command
                      and its expanded arguments or associated word list.
              --BB      The  shell performs brace expansion (see BBrraaccee EExxppaannssiioonn
                      above).  This is on by default.
              --CC      If set, bbaasshh does not overwrite an  existing  file  with
                      the  >>,  >>&&,  and <<>> redirection operators.  This may be
                      overridden when creating output files by using the redi-
                      rection operator >>|| instead of >>.
              --EE      If set, any trap on EERRRR is inherited by shell functions,
                      command substitutions, and commands executed in  a  sub-
                      shell  environment.  The EERRRR trap is normally not inher-
                      ited in such cases.
              --HH      Enable !!  style history substitution.  This option is on
                      by default when the shell is interactive.
              --PP      If  set,  the shell does not resolve symbolic links when
                      executing commands such as ccdd that  change  the  current
                      working  directory.   It  uses  the  physical  directory
                      structure instead.  By default, bbaasshh follows the logical
                      chain  of  directories  when  performing  commands which
                      change the current directory.
              --TT      If set, any traps on DDEEBBUUGG and RREETTUURRNN are  inherited  by
                      shell  functions,  command  substitutions,  and commands
                      executed in  a  subshell  environment.   The  DDEEBBUUGG  and
                      RREETTUURRNN traps are normally not inherited in such cases.
              ----      If  no arguments follow this option, then the positional
                      parameters are unset.  Otherwise, the positional parame-
                      ters  are  set  to  the _a_r_gs, even if some of them begin
                      with a --.
              --       Signal the end of options, cause all remaining  _a_r_gs  to
                      be assigned to the positional parameters.  The --xx and --vv
                      options are turned off.  If there are no _a_r_gs, the posi-
                      tional parameters remain unchanged.

              The  options are off by default unless otherwise noted.  Using +
              rather than - causes  these  options  to  be  turned  off.   The
              options  can  also be specified as arguments to an invocation of
              the shell.  The current set of options may be found in $$--.   The
              return status is always true unless an invalid option is encoun-
              tered.

       sshhiifftt [_n]
              The positional parameters from _n+1 ... are renamed  to  $$11  ........
              Parameters  represented  by  the  numbers  $$## down to $$##-_n+1 are
              unset.  _n must be a non-negative number less than  or  equal  to
              $$##.   If  _n is 0, no parameters are changed.  If _n is not given,
              it is assumed to be 1.  If _n is greater than $$##, the  positional
              parameters  are  not changed.  The return status is greater than
              zero if _n is greater than $$## or less than zero; otherwise 0.

       sshhoopptt [--ppqqssuu] [--oo] [_o_p_t_n_a_m_e ...]
              Toggle the values of settings controlling optional shell  behav-
              ior.   The settings can be either those listed below, or, if the
              --oo option is used, those available with the --oo option to the sseett
              builtin command.  With no options, or with the --pp option, a list
              of all settable options is  displayed,  with  an  indication  of
              whether or not each is set; if _o_p_t_n_a_m_e_s are supplied, the output
              is restricted to those options.  The --pp option causes output  to
              be  displayed  in  a  form  that  may be reused as input.  Other
              options have the following meanings:
              --ss     Enable (set) each _o_p_t_n_a_m_e.
              --uu     Disable (unset) each _o_p_t_n_a_m_e.
              --qq     Suppresses normal output (quiet mode); the return  status
                     indicates whether the _o_p_t_n_a_m_e is set or unset.  If multi-
                     ple _o_p_t_n_a_m_e arguments are given with --qq, the return  sta-
                     tus  is zero if all _o_p_t_n_a_m_e_s are enabled; non-zero other-
                     wise.
              --oo     Restricts the values of _o_p_t_n_a_m_e to be those  defined  for
                     the --oo option to the sseett builtin.

              If  either  --ss  or  --uu  is used with no _o_p_t_n_a_m_e arguments, sshhoopptt
              shows only those options which are set or  unset,  respectively.
              Unless  otherwise  noted, the sshhoopptt options are disabled (unset)
              by default.

              The return status when listing options is zero if  all  _o_p_t_n_a_m_e_s
              are  enabled,  non-zero  otherwise.   When  setting or unsetting
              options, the return status is zero unless an _o_p_t_n_a_m_e  is  not  a
              valid shell option.

              The list of sshhoopptt options is:

              aassssoocc__eexxppaanndd__oonnccee
                      If  set,  the  shell  suppresses  multiple evaluation of
                      associative array subscripts during  arithmetic  expres-
                      sion  evaluation, while executing builtins that can per-
                      form variable assignments, and while executing  builtins
                      that perform array dereferencing.
              aauuttooccdd  If  set,  a command name that is the name of a directory
                      is executed as if it were the argument to  the  ccdd  com-
                      mand.  This option is only used by interactive shells.
              ccddaabbllee__vvaarrss
                      If  set,  an  argument to the ccdd builtin command that is
                      not a directory is assumed to be the name of a  variable
                      whose value is the directory to change to.
              ccddssppeellll If set, minor errors in the spelling of a directory com-
                      ponent in a ccdd command will be  corrected.   The  errors
                      checked for are transposed characters, a missing charac-
                      ter, and one character too many.   If  a  correction  is
                      found,  the  corrected filename is printed, and the com-
                      mand proceeds.  This option is only used by  interactive
                      shells.
              cchheecckkhhaasshh
                      If set, bbaasshh checks that a command found in the hash ta-
                      ble exists before trying to execute  it.   If  a  hashed
                      command  no  longer exists, a normal path search is per-
                      formed.
              cchheecckkjjoobbss
                      If set, bbaasshh lists the status of any stopped and running
                      jobs  before  exiting an interactive shell.  If any jobs
                      are running, this causes the exit to be deferred until a
                      second  exit is attempted without an intervening command
                      (see JJOOBB CCOONNTTRROOLL above).   The  shell  always  postpones
                      exiting if any jobs are stopped.
              cchheecckkwwiinnssiizzee
                      If  set, bbaasshh checks the window size after each external
                      (non-builtin) command and,  if  necessary,  updates  the
                      values  of LLIINNEESS and CCOOLLUUMMNNSS.  This option is enabled by
                      default.
              ccmmddhhiisstt If set, bbaasshh attempts to save all lines of  a  multiple-
                      line  command  in  the  same history entry.  This allows
                      easy re-editing of multi-line commands.  This option  is
                      enabled  by  default,  but only has an effect if command
                      history is enabled, as described above under HHIISSTTOORRYY.
              ccoommppaatt3311
                      If set, bbaasshh changes its behavior to that of version 3.1
                      with  respect  to quoted arguments to the [[[[ conditional
                      command's ==~~ operator and locale-specific string compar-
                      ison  when  using  the  [[[[ conditional command's << and >>
                      operators.  Bash versions prior to  bash-4.1  use  ASCII
                      collation and _s_t_r_c_m_p(3); bash-4.1 and later use the cur-
                      rent locale's collation sequence and _s_t_r_c_o_l_l(3).
              ccoommppaatt3322
                      If set, bbaasshh changes its behavior to that of version 3.2
                      with  respect  to locale-specific string comparison when
                      using the [[[[ conditional command's  <<  and  >>  operators
                      (see  previous  item)  and  the effect of interrupting a
                      command list.  Bash versions 3.2  and  earlier  continue
                      with  the  next command in the list after one terminates
                      due to an interrupt.
              ccoommppaatt4400
                      If set, bbaasshh changes its behavior to that of version 4.0
                      with  respect  to locale-specific string comparison when
                      using the [[[[ conditional command's  <<  and  >>  operators
                      (see  description  of ccoommppaatt3311) and the effect of inter-
                      rupting a command list.  Bash  versions  4.0  and  later
                      interrupt  the  list as if the shell received the inter-
                      rupt; previous versions continue with the  next  command
                      in the list.
              ccoommppaatt4411
                      If  set, bbaasshh, when in _p_o_s_i_x _m_o_d_e, treats a single quote
                      in a double-quoted  parameter  expansion  as  a  special
                      character.   The  single quotes must match (an even num-
                      ber) and the characters between the  single  quotes  are
                      considered  quoted.   This is the behavior of posix mode
                      through version 4.1.  The default bash behavior  remains
                      as in previous versions.
              ccoommppaatt4422
                      If  set, bbaasshh does not process the replacement string in
                      the pattern  substitution  word  expansion  using  quote
                      removal.
              ccoommppaatt4433
                      If  set,  bbaasshh  does  not  print a warning message if an
                      attempt is made to use a quoted compound  array  assign-
                      ment  as  an  argument  to ddeeccllaarree, makes word expansion
                      errors non-fatal errors that cause the  current  command
                      to  fail  (the  default  behavior  is to make them fatal
                      errors that cause the shell to exit), and does not reset
                      the  loop  state when a shell function is executed (this
                      allows bbrreeaakk or ccoonnttiinnuuee in a shell function  to  affect
                      loops in the caller's context).
              ccoommppaatt4444
                      If   set,   bbaasshh  saves  the  positional  parameters  to
                      BASH_ARGV and BASH_ARGC before they are used, regardless
                      of whether or not extended debugging mode is enabled.
              ccoommpplleettee__ffuullllqquuoottee
                      If  set,  bbaasshh  quotes all shell metacharacters in file-
                      names and directory names  when  performing  completion.
                      If not set, bbaasshh removes metacharacters such as the dol-
                      lar sign from the set of characters that will be  quoted
                      in  completed filenames when these metacharacters appear
                      in shell variable references in words to  be  completed.
                      This  means  that  dollar  signs  in variable names that
                      expand to directories will not be quoted;  however,  any
                      dollar  signs appearing in filenames will not be quoted,
                      either.  This is active only when bash  is  using  back-
                      slashes  to quote completed filenames.  This variable is
                      set by default, which is the default  bash  behavior  in
                      versions through 4.2.
              ddiirreexxppaanndd
                      If  set,  bbaasshh replaces directory names with the results
                      of word expansion when performing  filename  completion.
                      This  changes  the contents of the readline editing buf-
                      fer.  If not set, bbaasshh attempts  to  preserve  what  the
                      user typed.
              ddiirrssppeellll
                      If  set,  bbaasshh attempts spelling correction on directory
                      names during word completion if the directory name  ini-
                      tially supplied does not exist.
              ddoottgglloobb If  set, bbaasshh includes filenames beginning with a `.' in
                      the results of pathname expansion.  The filenames  ````..''''
                      and  ````....''''   must always be matched explicitly, even if
                      ddoottgglloobb is set.
              eexxeeccffaaiill
                      If set, a non-interactive shell will not exit if it can-
                      not  execute  the  file  specified as an argument to the
                      eexxeecc builtin command.  An  interactive  shell  does  not
                      exit if eexxeecc fails.
              eexxppaanndd__aalliiaasseess
                      If  set,  aliases  are expanded as described above under
                      AALLIIAASSEESS.  This option is enabled by default for interac-
                      tive shells.
              eexxttddeebbuugg
                      If  set  at  shell  invocation,  arrange  to execute the
                      debugger profile before the shell starts,  identical  to
                      the  ----ddeebbuuggggeerr option.  If set after invocation, behav-
                      ior intended for use by debuggers is enabled:
                      11..     The --FF option to the ddeeccllaarree builtin displays the
                             source file name and line number corresponding to
                             each function name supplied as an argument.
                      22..     If the command run by the DDEEBBUUGG  trap  returns  a
                             non-zero  value,  the next command is skipped and
                             not executed.
                      33..     If the command run by the DDEEBBUUGG  trap  returns  a
                             value  of 2, and the shell is executing in a sub-
                             routine (a shell function or a shell script  exe-
                             cuted  by  the  ..  or ssoouurrccee builtins), the shell
                             simulates a call to rreettuurrnn.
                      44..     BBAASSHH__AARRGGCC and BBAASSHH__AARRGGVV are updated as  described
                             in their descriptions above.
                      55..     Function  tracing  is  enabled: command substitu-
                             tion, shell functions, and subshells invoked with
                             (( _c_o_m_m_a_n_d )) inherit the DDEEBBUUGG and RREETTUURRNN traps.
                      66..     Error  tracing  is enabled: command substitution,
                             shell functions, and  subshells  invoked  with  ((
                             _c_o_m_m_a_n_d )) inherit the EERRRR trap.
              eexxttgglloobb If set, the extended pattern matching features described
                      above under PPaatthhnnaammee EExxppaannssiioonn are enabled.
              eexxttqquuoottee
                      If set, $$'_s_t_r_i_n_g' and  $$"_s_t_r_i_n_g"  quoting  is  performed
                      within   $${{_p_a_r_a_m_e_t_e_r}}   expansions  enclosed  in  double
                      quotes.  This option is enabled by default.
              ffaaiillgglloobb
                      If set, patterns which fail to  match  filenames  during
                      pathname expansion result in an expansion error.
              ffoorrccee__ffiiggnnoorree
                      If  set,  the  suffixes  specified  by the FFIIGGNNOORREE shell
                      variable cause words to be ignored when performing  word
                      completion even if the ignored words are the only possi-
                      ble  completions.   See  SSHHEELLLL  VVAARRIIAABBLLEESS  above  for  a
                      description  of  FFIIGGNNOORREE.   This  option  is  enabled by
                      default.
              gglloobbaasscciiiirraannggeess
                      If set,  range  expressions  used  in  pattern  matching
                      bracket  expressions (see PPaatttteerrnn MMaattcchhiinngg above) behave
                      as if in the traditional C locale when  performing  com-
                      parisons.   That  is,  the  current  locale's  collating
                      sequence is not taken into account, so bb will  not  col-
                      late  between  AA  and  BB,  and upper-case and lower-case
                      ASCII characters will collate together.
              gglloobbssttaarr
                      If set, the pattern **** used in a pathname expansion con-
                      text  will  match all files and zero or more directories
                      and subdirectories.  If the pattern is followed by a  //,
                      only directories and subdirectories match.
              ggnnuu__eerrrrffmmtt
                      If set, shell error messages are written in the standard
                      GNU error message format.
              hhiissttaappppeenndd
                      If set, the history list is appended to the  file  named
                      by  the  value  of  the HHIISSTTFFIILLEE variable when the shell
                      exits, rather than overwriting the file.
              hhiissttrreeeeddiitt
                      If set, and rreeaaddlliinnee is being used, a user is given  the
                      opportunity to re-edit a failed history substitution.
              hhiissttvveerriiffyy
                      If  set, and rreeaaddlliinnee is being used, the results of his-
                      tory substitution are  not  immediately  passed  to  the
                      shell  parser.   Instead,  the  resulting line is loaded
                      into the rreeaaddlliinnee editing buffer, allowing further modi-
                      fication.
              hhoossttccoommpplleettee
                      If set, and rreeaaddlliinnee is being used, bbaasshh will attempt to
                      perform hostname completion when a word containing  a  @@
                      is   being  completed  (see  CCoommpplleettiinngg  under  RREEAADDLLIINNEE
                      above).  This is enabled by default.
              hhuuppoonneexxiitt
                      If set, bbaasshh will send SSIIGGHHUUPP to all jobs when an inter-
                      active login shell exits.
              iinnhheerriitt__eerrrreexxiitt
                      If  set,  command substitution inherits the value of the
                      eerrrreexxiitt option, instead of unsetting it in the  subshell
                      environment.   This option is enabled when _p_o_s_i_x _m_o_d_e is
                      enabled.
              iinntteerraaccttiivvee__ccoommmmeennttss
                      If set, allow a word beginning with ## to cause that word
                      and  all remaining characters on that line to be ignored
                      in an interactive  shell  (see  CCOOMMMMEENNTTSS  above).   This
                      option is enabled by default.
              llaassttppiippee
                      If  set,  and  job control is not active, the shell runs
                      the last command of a pipeline not executed in the back-
                      ground in the current shell environment.
              lliitthhiisstt If  set,  and  the ccmmddhhiisstt option is enabled, multi-line
                      commands are saved to the history with embedded newlines
                      rather than using semicolon separators where possible.
              llooccaallvvaarr__iinnhheerriitt
                      If set, local variables inherit the value and attributes
                      of a variable of the same name that exists at a previous
                      scope  before  any  new  value is assigned.  The nameref
                      attribute is not inherited.
              llooccaallvvaarr__uunnsseett
                      If set, calling uunnsseett on  local  variables  in  previous
                      function  scopes  marks  them so subsequent lookups find
                      them unset until that function returns. This is  identi-
                      cal  to the behavior of unsetting local variables at the
                      current function scope.
              llooggiinn__sshheellll
                      The shell sets this option if it is started as  a  login
                      shell  (see  IINNVVOOCCAATTIIOONN  above).   The  value may not be
                      changed.
              mmaaiillwwaarrnn
                      If set, and a file that bbaasshh is checking  for  mail  has
                      been  accessed  since  the last time it was checked, the
                      message ``The mail in _m_a_i_l_f_i_l_e has been read''  is  dis-
                      played.
              nnoo__eemmppttyy__ccmmdd__ccoommpplleettiioonn
                      If  set,  and  rreeaaddlliinnee  is  being  used,  bbaasshh will not
                      attempt to search the PPAATTHH for possible completions when
                      completion is attempted on an empty line.
              nnooccaasseegglloobb
                      If  set,  bbaasshh  matches  filenames in a case-insensitive
                      fashion when performing pathname expansion (see PPaatthhnnaammee
                      EExxppaannssiioonn above).
              nnooccaasseemmaattcchh
                      If  set,  bbaasshh  matches  patterns  in a case-insensitive
                      fashion when performing matching while executing ccaassee or
                      [[[[ conditional commands, when performing pattern substi-
                      tution word expansions, or when filtering possible  com-
                      pletions as part of programmable completion.
              nnuullllgglloobb
                      If  set,  bbaasshh allows patterns which match no files (see
                      PPaatthhnnaammee EExxppaannssiioonn above) to expand to  a  null  string,
                      rather than themselves.
              pprrooggccoommpp
                      If set, the programmable completion facilities (see PPrroo--
                      ggrraammmmaabbllee CCoommpplleettiioonn above) are enabled.  This option is
                      enabled by default.
              pprrooggccoommpp__aalliiaass
                      If  set,  and  programmable  completion is enabled, bbaasshh
                      treats a command name that doesn't have any  completions
                      as  a possible alias and attempts alias expansion. If it
                      has an  alias,  bbaasshh  attempts  programmable  completion
                      using  the  command  word  resulting  from  the expanded
                      alias.
              pprroommppttvvaarrss
                      If set, prompt strings undergo parameter expansion, com-
                      mand   substitution,  arithmetic  expansion,  and  quote
                      removal after being expanded as described  in  PPRROOMMPPTTIINNGG
                      above.  This option is enabled by default.
              rreessttrriicctteedd__sshheellll
                      The   shell  sets  this  option  if  it  is  started  in
                      restricted mode (see RREESSTTRRIICCTTEEDD SSHHEELLLL below).  The value
                      may  not be changed.  This is not reset when the startup
                      files are executed, allowing the startup files  to  dis-
                      cover whether or not a shell is restricted.
              sshhiifftt__vveerrbboossee
                      If  set,  the sshhiifftt builtin prints an error message when
                      the shift count exceeds the number of positional parame-
                      ters.
              ssoouurrcceeppaatthh
                      If set, the ssoouurrccee (..) builtin uses the value of PPAATTHH to
                      find the directory containing the file  supplied  as  an
                      argument.  This option is enabled by default.
              xxppgg__eecchhoo
                      If   set,  the  eecchhoo  builtin  expands  backslash-escape
                      sequences by default.

       ssuussppeenndd [--ff]
              Suspend the execution of this shell until it receives a  SSIIGGCCOONNTT
              signal.  A login shell cannot be suspended; the --ff option can be
              used to override this and force the suspension.  The return sta-
              tus  is  0  unless the shell is a login shell and --ff is not sup-
              plied, or if job control is not enabled.

       tteesstt _e_x_p_r
       [[ _e_x_p_r ]]
              Return a status of 0 (true) or 1 (false) depending on the evalu-
              ation of the conditional expression _e_x_p_r.  Each operator and op-
              erand must be a separate argument.  Expressions are composed  of
              the  primaries  described  above  under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS.
              tteesstt does not accept any options, nor does it accept and  ignore
              an argument of ---- as signifying the end of options.

              Expressions  may  be  combined  using  the  following operators,
              listed  in  decreasing  order  of  precedence.   The  evaluation
              depends  on the number of arguments; see below.  Operator prece-
              dence is used when there are five or more arguments.
              !! _e_x_p_r True if _e_x_p_r is false.
              (( _e_x_p_r ))
                     Returns the value of _e_x_p_r.  This may be used to  override
                     the normal precedence of operators.
              _e_x_p_r_1 -aa _e_x_p_r_2
                     True if both _e_x_p_r_1 and _e_x_p_r_2 are true.
              _e_x_p_r_1 -oo _e_x_p_r_2
                     True if either _e_x_p_r_1 or _e_x_p_r_2 is true.

              tteesstt and [[ evaluate conditional expressions using a set of rules
              based on the number of arguments.

              0 arguments
                     The expression is false.
              1 argument
                     The expression is true if and only if the argument is not
                     null.
              2 arguments
                     If the first argument is !!, the expression is true if and
                     only if the second argument is null.  If the first  argu-
                     ment  is  one  of  the unary conditional operators listed
                     above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS,  the  expression  is
                     true if the unary test is true.  If the first argument is
                     not a valid unary conditional operator, the expression is
                     false.
              3 arguments
                     The following conditions are applied in the order listed.
                     If the second argument is one of the  binary  conditional
                     operators listed above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the
                     result of the expression is the result of the binary test
                     using  the first and third arguments as operands.  The --aa
                     and --oo operators are  considered  binary  operators  when
                     there  are  three arguments.  If the first argument is !!,
                     the value is the negation of the two-argument test  using
                     the second and third arguments.  If the first argument is
                     exactly (( and the third argument is exactly )), the result
                     is  the one-argument test of the second argument.  Other-
                     wise, the expression is false.
              4 arguments
                     If the first argument is !!, the result is the negation of
                     the  three-argument  expression composed of the remaining
                     arguments.  Otherwise, the expression is parsed and eval-
                     uated  according  to  precedence  using  the rules listed
                     above.
              5 or more arguments
                     The expression  is  parsed  and  evaluated  according  to
                     precedence using the rules listed above.

              When  used  with  tteesstt  or [[, the << and >> operators sort lexico-
              graphically using ASCII ordering.

       ttiimmeess  Print the accumulated user and system times for  the  shell  and
              for processes run from the shell.  The return status is 0.

       ttrraapp [--llpp] [[_a_r_g] _s_i_g_s_p_e_c ...]
              The  command  _a_r_g  is  to  be  read  and executed when the shell
              receives signal(s) _s_i_g_s_p_e_c.  If _a_r_g is absent (and  there  is  a
              single  _s_i_g_s_p_e_c)  or  --,  each  specified signal is reset to its
              original disposition (the value it  had  upon  entrance  to  the
              shell).   If _a_r_g is the null string the signal specified by each
              _s_i_g_s_p_e_c is ignored by the shell and by the commands it  invokes.
              If  _a_r_g  is  not present and --pp has been supplied, then the trap
              commands associated with each  _s_i_g_s_p_e_c  are  displayed.   If  no
              arguments  are  supplied or if only --pp is given, ttrraapp prints the
              list of commands associated with each  signal.   The  --ll  option
              causes  the shell to print a list of signal names and their cor-
              responding numbers.   Each  _s_i_g_s_p_e_c  is  either  a  signal  name
              defined  in  <_s_i_g_n_a_l_._h>,  or  a signal number.  Signal names are
              case insensitive and the SSIIGG prefix is optional.

              If a _s_i_g_s_p_e_c is EEXXIITT (0) the command _a_r_g  is  executed  on  exit
              from  the shell.  If a _s_i_g_s_p_e_c is DDEEBBUUGG, the command _a_r_g is exe-
              cuted before every _s_i_m_p_l_e _c_o_m_m_a_n_d, _f_o_r  command,  _c_a_s_e  command,
              _s_e_l_e_c_t  command,  every  arithmetic  _f_o_r command, and before the
              first command executes in a shell function  (see  SSHHEELLLL  GGRRAAMMMMAARR
              above).   Refer to the description of the eexxttddeebbuugg option to the
              sshhoopptt builtin for details of its effect on the DDEEBBUUGG trap.  If a
              _s_i_g_s_p_e_c is RREETTUURRNN, the command _a_r_g is executed each time a shell
              function or a script executed with the .. or ssoouurrccee builtins fin-
              ishes executing.

              If  a  _s_i_g_s_p_e_c  is  EERRRR,  the command _a_r_g is executed whenever a
              pipeline (which may consist of a single simple command), a list,
              or a compound command returns a non-zero exit status, subject to
              the following conditions.  The EERRRR trap is not executed  if  the
              failed command is part of the command list immediately following
              a wwhhiillee or uunnttiill keyword, part of the test in an  _i_f  statement,
              part of a command executed in a &&&& or |||| list except the command
              following the final &&&& or ||||, any command in a pipeline but  the
              last,  or  if the command's return value is being inverted using
              !!.  These are the same conditions obeyed  by  the  eerrrreexxiitt  (--ee)
              option.

              Signals  ignored  upon  entry  to the shell cannot be trapped or
              reset.  Trapped signals that are not being ignored are reset  to
              their original values in a subshell or subshell environment when
              one is created.  The return status is false if  any  _s_i_g_s_p_e_c  is
              invalid; otherwise ttrraapp returns true.

       ttyyppee [--aaffttppPP] _n_a_m_e [_n_a_m_e ...]
              With  no options, indicate how each _n_a_m_e would be interpreted if
              used as a command name.  If the --tt option is used, ttyyppee prints a
              string  which  is  one  of _a_l_i_a_s, _k_e_y_w_o_r_d, _f_u_n_c_t_i_o_n, _b_u_i_l_t_i_n, or
              _f_i_l_e if  _n_a_m_e  is  an  alias,  shell  reserved  word,  function,
              builtin,  or disk file, respectively.  If the _n_a_m_e is not found,
              then nothing  is  printed,  and  an  exit  status  of  false  is
              returned.   If  the  --pp  option is used, ttyyppee either returns the
              name of the disk file that would be executed if _n_a_m_e were speci-
              fied as a command name, or nothing if ``type -t name'' would not
              return _f_i_l_e.  The --PP option forces a PPAATTHH search for each  _n_a_m_e,
              even if ``type -t name'' would not return _f_i_l_e.  If a command is
              hashed, --pp and --PP print the hashed value, which is not necessar-
              ily  the  file  that appears first in PPAATTHH.  If the --aa option is
              used, ttyyppee prints all of the places that contain  an  executable
              named _n_a_m_e.  This includes aliases and functions, if and only if
              the --pp option is not also used.  The table of hashed commands is
              not  consulted  when  using  --aa.  The --ff option suppresses shell
              function lookup, as with the ccoommmmaanndd builtin.  ttyyppee returns true
              if all of the arguments are found, false if any are not found.

       uulliimmiitt [--HHSSaabbccddeeffiikkllmmnnppqqrrssttuuvvxxPPTT [_l_i_m_i_t]]
              Provides  control  over the resources available to the shell and
              to processes started by it, on systems that allow such  control.
              The --HH and --SS options specify that the hard or soft limit is set
              for the given resource.  A hard limit cannot be increased  by  a
              non-root  user  once it is set; a soft limit may be increased up
              to the value of the hard limit.  If neither --HH nor --SS is  speci-
              fied, both the soft and hard limits are set.  The value of _l_i_m_i_t
              can be a number in the unit specified for the resource or one of
              the special values hhaarrdd, ssoofftt, or uunnlliimmiitteedd, which stand for the
              current hard limit,  the  current  soft  limit,  and  no  limit,
              respectively.   If  _l_i_m_i_t  is  omitted, the current value of the
              soft limit of the resource is printed, unless the --HH  option  is
              given.  When more than one resource is specified, the limit name
              and unit are printed before the value.  Other options are inter-
              preted as follows:
              --aa     All current limits are reported
              --bb     The maximum socket buffer size
              --cc     The maximum size of core files created
              --dd     The maximum size of a process's data segment
              --ee     The maximum scheduling priority ("nice")
              --ff     The  maximum  size  of files written by the shell and its
                     children
              --ii     The maximum number of pending signals
              --kk     The maximum number of kqueues that may be allocated
              --ll     The maximum size that may be locked into memory
              --mm     The maximum resident set size (many systems do not  honor
                     this limit)
              --nn     The maximum number of open file descriptors (most systems
                     do not allow this value to be set)
              --pp     The pipe size in 512-byte blocks (this may not be set)
              --qq     The maximum number of bytes in POSIX message queues
              --rr     The maximum real-time scheduling priority
              --ss     The maximum stack size
              --tt     The maximum amount of cpu time in seconds
              --uu     The maximum number of processes  available  to  a  single
                     user
              --vv     The  maximum  amount  of  virtual memory available to the
                     shell and, on some systems, to its children
              --xx     The maximum number of file locks
              --PP     The maximum number of pseudoterminals
              --TT     The maximum number of threads

              If _l_i_m_i_t is given, and the --aa option is not used, _l_i_m_i_t  is  the
              new  value  of  the  specified resource.  If no option is given,
              then --ff is assumed.  Values are in 1024-byte increments,  except
              for  --tt,  which is in seconds; --pp, which is in units of 512-byte
              blocks; --PP, --TT, --bb, --kk, --nn, and --uu, which are  unscaled  values;
              and, when in posix mode, --cc and --ff, which are in 512-byte incre-
              ments.  The return status is 0 unless an invalid option or argu-
              ment is supplied, or an error occurs while setting a new limit.

       uummaasskk [--pp] [--SS] [_m_o_d_e]
              The user file-creation mask is set to _m_o_d_e.  If _m_o_d_e begins with
              a digit, it is interpreted as an octal number; otherwise  it  is
              interpreted  as a symbolic mode mask similar to that accepted by
              _c_h_m_o_d(1).  If _m_o_d_e is omitted, the current value of the mask  is
              printed.   The  --SS  option causes the mask to be printed in sym-
              bolic form; the default output is an octal number.   If  the  --pp
              option is supplied, and _m_o_d_e is omitted, the output is in a form
              that may be reused as input.  The return status is 0 if the mode
              was  successfully  changed  or if no _m_o_d_e argument was supplied,
              and false otherwise.

       uunnaalliiaass [-aa] [_n_a_m_e ...]
              Remove each _n_a_m_e from the list of defined  aliases.   If  --aa  is
              supplied,  all  alias definitions are removed.  The return value
              is true unless a supplied _n_a_m_e is not a defined alias.

       uunnsseett [-ffvv] [-nn] [_n_a_m_e ...]
              For each _n_a_m_e, remove the corresponding  variable  or  function.
              If the --vv option is given, each _n_a_m_e refers to a shell variable,
              and that variable is removed.  Read-only variables  may  not  be
              unset.   If  --ff  is specified, each _n_a_m_e refers to a shell func-
              tion, and the function definition is removed.  If the --nn  option
              is  supplied, and _n_a_m_e is a variable with the _n_a_m_e_r_e_f attribute,
              _n_a_m_e will be unset rather than the variable it  references.   --nn
              has  no  effect if the --ff option is supplied.  If no options are
              supplied, each _n_a_m_e refers to a variable; if there is  no  vari-
              able  by  that name, any function with that name is unset.  Each
              unset variable or  function  is  removed  from  the  environment
              passed  to subsequent commands.  If any of CCOOMMPP__WWOORRDDBBRREEAAKKSS, RRAANN--
              DDOOMM, SSEECCOONNDDSS, LLIINNEENNOO, HHIISSTTCCMMDD, FFUUNNCCNNAAMMEE, GGRROOUUPPSS, or DDIIRRSSTTAACCKK are
              unset, they lose their special properties, even if they are sub-
              sequently reset.  The exit status is true unless a _n_a_m_e is read-
              only.

       wwaaiitt [--ffnn] [_i_d _._._.]
              Wait for each specified child process and return its termination
              status.  Each _i_d may be a process ID or a job specification;  if
              a  job  spec  is given, all processes in that job's pipeline are
              waited for.  If _i_d is not given, all currently active child pro-
              cesses are waited for, and the return status is zero.  If the --nn
              option is supplied, wwaaiitt waits for  any  job  to  terminate  and
              returns  its exit status.  If the --ff option is supplied, and job
              control is enabled, wwaaiitt forces _i_d to terminate before returning
              its  status, instead of returning when it changes status.  If _i_d
              specifies a non-existent process or job, the  return  status  is
              127.   Otherwise,  the  return  status is the exit status of the
              last process or job waited for.

SSEEEE AALLSSOO
       bash(1), sh(1)



GNU Bash 5.0                      2004 Apr 20                 BASH_BUILTINS(1)
