path: root/doc/builtins.0

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, bbrreeaakk, ccoonnttiinnuuee, lleett,
       and  sshhiifftt builtins accept and process arguments beginning with -- with-
       out 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 interpretation.
       :: [_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; _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] [--DDEE] [--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 [--DDEE] [_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  the
              remaining options and actions should apply  to  the  ``default''
              command  completion;  that is, completion attempted on a command
              for which no completion has previously  been  defined.   The  --EE
              option  indicates  that the remaining options and actions should
              apply to  ``empty''  command  completion;  that  is,  completion
              attempted on a blank line.

              The  process  of  applying  these completion specifications when
              word completion is attempted is described above  under  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.   The possible completions are the members
                      of the resultant list which match the  word  being  com-
                      pleted.
              --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] [--DDEE] [++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 the remaining
              options should apply to the ``default'' command completion; that
              is,  completion  attempted  on a command for which no completion
              has previously been defined.  The --EE option indicates  that  the
              remaining  options should apply to ``empty'' command completion;
              that is, completion attempted on a blank line.

              The return value is true unless an invalid option  is  supplied,
              an attempt is made to modify the options for a _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 the function 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
              following 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  for
                     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 may not be used to destroy an array vari-
              able 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 vari-
              able  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  assignment
              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.
              --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 ...]
              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.  If _c_o_m_m_a_n_d is not specified, any redi-
              rections take effect in the current shell, and the return status
              is 0.  If there is a redirection error, the return status is 1.

       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 intepreted  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 --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.
              --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 previous history line.  The return value is 0
              unless  an  invalid option is encountered, an error occurs while
              reading or writing the history file, an invalid _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 [_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.  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.
              --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 (except that \\cc terminates output,
                     backslashes in \\'', \\"", and \\?? are not removed, and  octal
                     escapes beginning with \\00 may contain up to four digits).
              %%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, 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 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, 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, with leftover words and their  interven-
              ing  separators  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  values.  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 back-
              slash character (\\) may be used to remove  any  special  meaning
              for the next character read and for line continuation.  Options,
              if supplied, have the following meanings:
              --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.
              --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.
              --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 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 mode, only shell variables  are  listed.
              The  output  is  sorted  according  to the current locale.  When
              options are specified, they set or unset shell attributes.   Any
              arguments  remaining after 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.  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:

              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 command
                      and, if necessary, updates the values of LLIINNEESS and  CCOOLL--
                      UUMMNNSS.
              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.
              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).
              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 mode, 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.
              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.
              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,  behavior  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.
              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.
              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.
              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  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 [--nn] [_n _._._.]
              Wait for each specified child process and return its termination
              status.  Each _n may be a process ID or a job specification; if a
              job spec is given, all processes  in  that  job's  pipeline  are
              waited  for.  If _n is not given, all currently active child pro-
              cesses are waited for, and the return status is zero.  If the --nn
              option  is  supplied,  wwaaiitt  waits  for any job to terminate and
              returns its exit status.  If _n specifies a non-existent  process
              or  job, the return status is 127.  Otherwise, the return status
              is the exit status of the last process or job waited for.

SSEEEE AALLSSOO
       bash(1), sh(1)



GNU Bash-4.2                      2004 Apr 20                 BASH_BUILTINS(1)