BASH_BUILTINS(1)                                              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.   For  example,  the  ::, ttrruuee, ffaallssee, and tteesstt builtins do not
       accept options.
       :: [_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.  A zero exit code is
              returned.

        ..  _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, file
              names  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.  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] [--llppssvvPPSSVV]
       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 _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.

              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] [_d_i_r]
              Change  the  current directory to _d_i_r.  The variable HHOOMMEE is the
              default _d_i_r.  The variable CCDDPPAATTHH defines the  search  path  for
              the  directory  containing  _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  says  to use the physical directory structure instead of
              following symbolic links (see also the  --PP  option  to  the  sseett
              builtin command); the --LL option forces symbolic links to be fol-
              lowed.  An argument of -- is equivalent to $$OOLLDDPPWWDD.   If  a  non-
              empty  directory  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  success-
              fully 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 file name
              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  pro-
              grammable  completion  code  had  generated them directly from a
              completion specification with the same flags.  If _w_o_r_d is speci-
              fied, 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] [--EE] [--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 [--EE] [_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  --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  PPrroo--
              ggrraammmmaabbllee 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.
                      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.
              --GG _g_l_o_b_p_a_t
                      The filename expansion pattern _g_l_o_b_p_a_t  is  expanded  to
                      generate the possible completions.
              --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.
              --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 it finishes, the possible com-
                      pletions are retrieved from the value of  the  CCOOMMPPRREEPPLLYY
                      array variable.
              --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 filename 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.
              --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.

              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] [++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-execution 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 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 comple-
       tion 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 [--aaAAffFFiillrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...]
       ttyyppeesseett [--aaAAffFFiillrrttuuxx] [--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 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 defi-
              nitions;  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 dis-
              played as well.   The  --FF  option  implies  --ff.   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 )) 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.
              --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 wwiillll nnoott rreemmoovvee tthhee rreeaaddoonnllyy aattttrriibbuuttee..  WWhheenn uusseedd
              iinn aa ffuunnccttiioonn,, mmaakkeess eeaacchh _n_a_m_e llooccaall,, aass wwiitthh tthhee llooccaall command.
              If a variable name is followed by =_v_a_l_u_e, the value of the vari-
              able is set to _v_a_l_u_e.  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 readonly status for a read-
              only  variable,  an attempt is made to turn off array status for
              an array variable, or an attempt is made to display a  non-exis-
              tent function with --ff.

       ddiirrss [[++_n]] [[--_n]] [[--ccppllvv]]
              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.
              ++_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.
              --cc     Clears  the  directory  stack  by  deleting  all  of  the
                     entries.
              --ll     Produces a longer listing;  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.

              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,  each  _j_o_b_s_p_e_c  is  removed  from the table of
              active jobs.  If _j_o_b_s_p_e_c is not present, and neither --aa  nnoorr  --rr
              iiss  ssuupppplliieedd,, tthhee sshheellll''ss nnoottiioonn ooff tthhee _c_u_r_r_e_n_t _j_o_b iiss uusseedd..  IIff
              tthhee --hh ooppttiioonn iiss ggiivveenn,, eeaacchh _j_o_b_s_p_e_c is not removed from the ta-
              ble,  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 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 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 always 0.  If --nn is specified, the trailing
              newline  is  suppressed.  If the --ee option is given, interpreta-
              tion of the following backslash-escaped characters  is  enabled.
              The  --EE option disables the interpretation of these escape char-
              acters, 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     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)

       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  shell  option eexxeeccffaaiill is enabled, in which 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 all names that are
              exported in this shell 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 supplied with a _n_a_m_e that is not a func-
              tion.

       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]
              Fix Command.  In the first form, a range of commands from  _f_i_r_s_t
              to  _l_a_s_t  is selected from the history list.  _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 cur-
              rent 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 otherwise.  If _f_i_r_s_t is not spec-
              ified it is set to the previous command 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, is used.  When editing is complete,
              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.  A useful alias to use with this is
              ``r="fc -s"'', so that typing ``r cc''  runs  the  last  command
              beginning with ``cc'' and typing ``r'' re-executes the last com-
              mand.

              If the first form is used, the  return  value  is  0  unless  an
              invalid  option  is encountered or _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 nnaammee 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]
              For  each  _n_a_m_e, the full file name of the command is determined
              by searching the directories in $$PPAATTHH and remembered.  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 file name 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  arguments  are
              supplied  with  --tt,  the  _n_a_m_e is printed before the hashed full
              pathname.  The --ll option causes output to be displayed in a for-
              mat  that may be reused as input.  If no arguments are given, or
              if only --ll is supplied, information about remembered 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 (history lines entered
                     since the beginning of the current bbaasshh session)  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 use them as the
                     current history.
              --ww     Write  the current history to the history file, overwrit-
                     ing 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 is set, the time stamp information associ-
              ated with each history entry is written  to  the  history  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  supplied  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.
              --pp     List  only  the  process  ID  of  the job's process group
                     leader.
              --nn     Display information only about  jobs  that  have  changed
                     status  since the user was last notified of their status.
              --rr     Restrict output to running jobs.
              --ss     Restrict output to 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).  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.  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  [--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  [--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 array variable _a_r_r_a_y, or
              from file descriptor _f_d if the --uu option is supplied.  The vari-
              able  MMAAPPFFIILLEE  is the default _a_r_r_a_y.  Options, if supplied, have
              the following meanings:
              --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 line 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 as an additional argument.  _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, or _a_r_r_a_y is invalid or unassignable.

       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 _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  for-
              mat  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) for-
              mats,  %%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), and %%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.

              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  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.

              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] [-- _t_e_x_t] [--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.  The backslash character (\\)  may  be
              used  to  remove any special meaning for the next character read
              and for line continuation.  Options, if supplied, have the  fol-
              lowing 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.
              --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 is not read within _t_i_m_e_o_u_t seconds.  _t_i_m_e_-
                     _o_u_t may be a decimal number  with  a  fractional  portion
                     following  the decimal point.  This option is only effec-
                     tive if rreeaadd is reading input from a terminal,  pipe,  or
                     other  special  file;  it has no effect when reading from
                     regular files.  If _t_i_m_e_o_u_t is 0, rreeaadd returns success  if
                     input  is  available  on  the  specified file descriptor,
                     failure otherwise.  The exit status is greater  than  128
                     if the timeout is exceeded.
              --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 return code  is  zero,  unless  end-of-file  is
              encountered,  rreeaadd  times  out (in which case the return code is
              greater than 128), or an invalid file descriptor is supplied  as
              the argument to --uu.

       rreeaaddoonnllyy [--aaAAppff] [_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 no _n_a_m_e arguments are given, or if the --pp option  is
              supplied,  a  list  of  all  readonly  names is printed.  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 exit with the return value specified by _n.
              If _n is omitted, the return status is that of the  last  command
              executed  in the function body.  If used outside a function, but
              during execution of a script by  the  ..   (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 used outside a
              function and not during execution of a script by ..,  the  return
              status is false.  Any command associated with the RREETTUURRNN trap is
              executed before execution resumes after the function or  script.

       sseett [----aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [--oo _o_p_t_i_o_n] [_a_r_g ...]
       sseett [++aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [++oo _o_p_t_i_o_n] [_a_r_g ...]
              Without  options,  the name and value of each shell variable are
              displayed in a format that can be reused as input for setting or
              resetting the currently-set variables.  Read-only variables can-
              not be reset.  In _p_o_s_i_x _m_o_d_e, only shell variables  are  listed.
              The  output  is  sorted  according  to the current locale.  When
              options are specified, they set or unset shell attributes.   Any
              arguments  remaining after option processing are treated as val-
              ues for the positional parameters and are assigned, in order, to
              $$11,  $$22,  ......   $$_n.   Options,  if specified, have the following
              meanings:
              --aa      Automatically mark variables  and  functions  which  are
                      modified  or  created  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 _s_i_m_p_l_e _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 in an iiff statement, part of  a  command
                      executed  in  a &&&& or |||| list, any command in a pipeline
                      but the last, or if the command's return value is  being
                      inverted  via  !!.  Failing simple commands that are part
                      of shell functions or command lists enclosed  in  braces
                      or  parentheses  satisfying  the above conditions do not
                      cause the shell to exit.  A trap on EERRRR, if set, is exe-
                      cuted before the shell exits.
              --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).   Background  pro-
                      cesses  run  in a separate process group and a line con-
                      taining their exit status is printed upon their  comple-
                      tion.
              --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.
                      eerrrrttrraaccee
                              Same as --EE.
                      ffuunnccttrraaccee
                              Same as --TT.
                      eerrrreexxiitt Same as --ee.
                      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).
                      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,
                      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 supplied, these
                      actions are taken and the effective user id  is  set  to
                      the  real  user  id.   If  the  --pp option is supplied at
                      startup, the effective user id is  not  reset.   Turning
                      this  option off causes the effective user and group ids
                      to be set to the real user and group ids.
              --tt      Exit after reading and executing one command.
              --uu      Treat unset variables as an error when performing param-
                      eter  expansion.   If expansion is attempted on an unset
                      variable, 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 follow  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 variables controlling optional shell behav-
              ior.  With no options, or with the --pp option, a list of all set-
              table 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 fol-
              lowing 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, the dis-
              play is limited to those options which are set or unset, respec-
              tively.   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 file name 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 com-
                      mand's =~ operator.
              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), a call to
                             rreettuurrnn is simulated.
                      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 EERRRROORR 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.
              gglloobbssttaarr
                      If set, the pattern **** used in a filename expansion con-
                      text will match a 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.
              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.
              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 or 1 depending on the evaluation of the
              conditional expression _e_x_p_r.  Each operator and operand 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.
              !! _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
                     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.

       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 SIG 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 executed 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 EERRRR,
              the command _a_r_g is executed whenever  a  simple  command  has  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, or if the command's return value is being
              inverted via !!.  These are the same  conditions  obeyed  by  the
              eerrrreexxiitt option.  If a _s_i_g_s_p_e_c is RREETTUURRNN, the command _a_r_g is exe-
              cuted each time a shell function or a script executed with the ..
              or  ssoouurrccee  builtins  finishes  executing.  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 child process when it 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,  not  necessarily  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 func-
              tion lookup, as with the ccoommmmaanndd builtin.  ttyyppee returns true  if
              all of the arguments are found, false if any are not found.

       uulliimmiitt [--HHSSTTaabbccddeeffiillmmnnppqqrrssttuuvvxx [_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
              --ll     The maximum size that may be locked into memory
              --mm     The maximum resident set size
              --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
              --xx     The maximum number of file locks
              --TT     The maximum number of threads

              If _l_i_m_i_t is given, it is the new value of the specified resource
              (the --aa option is display only).  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,
              and  --TT,  --bb, --nn, and --uu, which are unscaled values.  The return
              status is 0 unless an invalid option or argument is supplied, or
              an error occurs while setting a new limit.

       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] [_n_a_m_e ...]
              For each _n_a_m_e, remove the corresponding  variable  or  function.
              If no options are supplied, or the --vv option is given, each _n_a_m_e
              refers to a shell variable.   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.  Each unset  vari-
              able  or function is removed from the environment passed to sub-
              sequent commands.  If any of RRAANNDDOOMM, SSEECCOONNDDSS,  LLIINNEENNOO,  HHIISSTTCCMMDD,
              FFUUNNCCNNAAMMEE, GGRROOUUPPSS, or DDIIRRSSTTAACCKK are unset, they lose their special
              properties, even if they are subsequently reset.  The exit  sta-
              tus is true unless a _n_a_m_e is readonly.

       wwaaiitt [_n _._._.]
              Wait  for each specified process and return its termination sta-
              tus.  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 _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-4.0                      2004 Apr 20                 BASH_BUILTINS(1)
