_B_A_S_H___B_U_I_L_T_I_N_S(1)            General Commands Manual           _B_A_S_H___B_U_I_L_T_I_N_S(1)

NNAAMMEE
       :, ., [, 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,
       readarray,  readonly, return, set, shift, shopt, source, suspend, test,
       times, trap, true, type, typeset, ulimit, umask, unalias, unset, wait -
       bash built-in commands, see bbaasshh(1)

BBAASSHH BBUUIILLTTIINN CCOOMMMMAANNDDSS
       Unless otherwise noted, each builtin command documented in this section
       as accepting options preceded by -- accepts ---- to signify the end of the
       options.  The ::, ttrruuee, ffaallssee, and tteesstt/[[ builtins do not accept options
       and do not treat ---- specially.  The eexxiitt, llooggoouutt, rreettuurrnn,  bbrreeaakk,  ccoonn--
       ttiinnuuee,  lleett,  and sshhiifftt builtins accept and process arguments beginning
       with -- without requiring ----.  Other builtins that accept arguments  but
       are  not  specified  as accepting options interpret arguments beginning
       with -- as invalid options and require ---- to  prevent  this  interpreta-
       tion.

       :: [_a_r_g_u_m_e_n_t_s]
              No  effect;  the command does nothing beyond expanding _a_r_g_u_m_e_n_t_s
              and performing any specified redirections.  The return status is
              zero.

       .. [--pp _p_a_t_h] _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s]
       ssoouurrccee [--pp _p_a_t_h] _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s]
              The .. command (ssoouurrccee) reads and execute commands from  _f_i_l_e_n_a_m_e
              in  the current shell environment and returns the exit status of
              the last command executed from _f_i_l_e_n_a_m_e.

              If _f_i_l_e_n_a_m_e does not contain a slash, .. searches for it.  If the
              --pp option is supplied, .. treats _p_a_t_h as a  colon-separated  list
              of  directories in which to find _f_i_l_e_n_a_m_e; otherwise, .. uses the
              entries in PPAATTHH  to  find  the  directory  containing  _f_i_l_e_n_a_m_e.
              _f_i_l_e_n_a_m_e  does  not  need to be executable.  When bbaasshh is not in
              posix mode, it searches the current directory if _f_i_l_e_n_a_m_e is not
              found in PPAATTHH, but does not search the current directory  if  --pp
              is supplied.  If the ssoouurrcceeppaatthh option to the sshhoopptt builtin com-
              mand is turned off, .. does not search PPAATTHH.

              If  any _a_r_g_u_m_e_n_t_s are supplied, they become the positional para-
              meters when _f_i_l_e_n_a_m_e is executed.  Otherwise the positional  pa-
              rameters are unchanged.

              If the --TT option is enabled, .. inherits any trap on DDEEBBUUGG; if it
              is  not,  any DDEEBBUUGG trap string is saved and restored around the
              call to .., and .. unsets the DDEEBBUUGG trap while it executes.  If --TT
              is not set, and the sourced file changes the DDEEBBUUGG trap, the new
              value persists after .. completes.  The return status is the sta-
              tus of the last command executed from _f_i_l_e_n_a_m_e (0 if no commands
              are executed), and non-zero 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] ...]
              With  no  arguments or with the --pp option, aalliiaass 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, define an alias 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
              during  command parsing.  For each _n_a_m_e in the argument list for
              which no _v_a_l_u_e is supplied, print the  name  and  value  of  the
              alias  _n_a_m_e.  aalliiaass returns true unless a _n_a_m_e is given (without
              a corresponding =_v_a_l_u_e) 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
              uses its notion of the _c_u_r_r_e_n_t _j_o_b.  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] [--llssvvSSVVXX]
       bbiinndd [--mm _k_e_y_m_a_p] [--qq _f_u_n_c_t_i_o_n] [--uu _f_u_n_c_t_i_o_n] [--rr _k_e_y_s_e_q]
       bbiinndd [--mm _k_e_y_m_a_p] --ff _f_i_l_e_n_a_m_e
       bbiinndd [--mm _k_e_y_m_a_p] --xx _k_e_y_s_e_q[:] _s_h_e_l_l_-_c_o_m_m_a_n_d
       bbiinndd [--mm _k_e_y_m_a_p] _k_e_y_s_e_q:_f_u_n_c_t_i_o_n_-_n_a_m_e
       bbiinndd [--mm _k_e_y_m_a_p] --pp|--PP [_r_e_a_d_l_i_n_e_-_c_o_m_m_a_n_d]
       bbiinndd [--mm _k_e_y_m_a_p] _k_e_y_s_e_q:_r_e_a_d_l_i_n_e_-_c_o_m_m_a_n_d
       bbiinndd _r_e_a_d_l_i_n_e_-_c_o_m_m_a_n_d_-_l_i_n_e
              Display current rreeaaddlliinnee key and function bindings, bind  a  key
              sequence  to a rreeaaddlliinnee function or macro or to a shell command,
              or set a rreeaaddlliinnee variable.  Each non-option argument is  a  key
              binding  or command as it would appear in a rreeaaddlliinnee initializa-
              tion file such as _._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.  In the following descriptions, output avail-
              able to be re-read is formatted as commands that would appear in
              a rreeaaddlliinnee initialization file or that would be supplied as  in-
              dividual  arguments  to  a  bbiinndd command.  Options, if supplied,
              have the following meanings:
              --mm _k_e_y_m_a_p
                     Use _k_e_y_m_a_p as the keymap to be affected by the subsequent
                     bindings.  Acceptable _k_e_y_m_a_p names are _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_-
                     _d_a_r_d_, _e_m_a_c_s_-_m_e_t_a_, _e_m_a_c_s_-_c_t_l_x_,  _v_i_,  _v_i_-_m_o_v_e_,  _v_i_-_c_o_m_m_a_n_d,
                     and  _v_i_-_i_n_s_e_r_t.   _v_i is equivalent to _v_i_-_c_o_m_m_a_n_d (_v_i_-_m_o_v_e
                     is also a synonym); _e_m_a_c_s is  equivalent  to  _e_m_a_c_s_-_s_t_a_n_-
                     _d_a_r_d.
              --ll     List the names of all rreeaaddlliinnee functions.
              --pp     Display  rreeaaddlliinnee  function  names and bindings in such a
                     way that they can be used as an argument to a  subsequent
                     bbiinndd  command  or  in a rreeaaddlliinnee initialization file.  If
                     arguments remain after  option  processing,  bbiinndd  treats
                     them  as  rreeaaddlliinnee  command names and restricts output to
                     those names.
              --PP     List current rreeaaddlliinnee function names  and  bindings.   If
                     arguments  remain  after  option  processing, bbiinndd treats
                     them as rreeaaddlliinnee command names and  restricts  output  to
                     those names.
              --ss     Display  rreeaaddlliinnee  key  sequences bound to macros and the
                     strings they output in such a way that they can  be  used
                     as an argument to a subsequent bbiinndd command or in a rreeaadd--
                     lliinnee initialization file.
              --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 used as an argument to a subsequent bbiinndd
                     command or in a rreeaaddlliinnee initialization file.
              --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
                     Display  key  sequences  that  invoke  the named rreeaaddlliinnee
                     _f_u_n_c_t_i_o_n.
              --uu _f_u_n_c_t_i_o_n
                     Unbind all key sequences  bound  to  the  named  rreeaaddlliinnee
                     _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 en-
                     tered.  The separator between _k_e_y_s_e_q and _s_h_e_l_l_-_c_o_m_m_a_n_d is
                     either  whitespace  or  a  colon  optionally  followed by
                     whitespace.  If the separator is  whitespace,  _s_h_e_l_l_-_c_o_m_-
                     _m_a_n_d  must  be enclosed in double quotes and rreeaaddlliinnee ex-
                     pands any of its special backslash-escapes in  _s_h_e_l_l_-_c_o_m_-
                     _m_a_n_d  before saving it.  If the separator is a colon, any
                     enclosing double quotes are optional, and  rreeaaddlliinnee  does
                     not  expand  the  command string before saving it.  Since
                     the entire key binding expression must be a single  argu-
                     ment,  it  should  be  enclosed  in  single quotes.  When
                     _s_h_e_l_l_-_c_o_m_m_a_n_d is  executed,  the  shell  sets  the  RREEAADD--
                     LLIINNEE__LLIINNEE  variable  to the contents of the rreeaaddlliinnee line
                     buffer and the RREEAADDLLIINNEE__PPOOIINNTT and RREEAADDLLIINNEE__MMAARRKK variables
                     to the current location of the insertion  point  and  the
                     saved  insertion  point  (the  mark),  respectively.  The
                     shell assigns any numeric argument the user  supplied  to
                     the  RREEAADDLLIINNEE__AARRGGUUMMEENNTT  variable.   If there was no argu-
                     ment, that variable is not set.  If the executed  command
                     changes   the   value  of  any  of  RREEAADDLLIINNEE__LLIINNEE,  RREEAADD--
                     LLIINNEE__PPOOIINNTT, or RREEAADDLLIINNEE__MMAARRKK, those new  values  will  be
                     reflected in the editing state.
              --XX     List  all  key  sequences bound to shell commands and the
                     associated commands in a format that can be reused as  an
                     argument to a subsequent bbiinndd command.

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

       bbrreeaakk [_n]
              Exit from within a ffoorr, wwhhiillee, uunnttiill, or sseelleecctt loop.  If  _n  is
              specified, bbrreeaakk exits _n enclosing loops.  _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  _s_h_e_l_l_-_b_u_i_l_t_i_n,  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 functionality of the builtin within the function.
              The ccdd builtin is commonly redefined this way.  The return  sta-
              tus 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).

              Without  _e_x_p_r,  ccaalllleerr displays the line number and source file-
              name of the current subroutine call.  If a non-negative  integer
              is supplied as _e_x_p_r, ccaalllleerr displays the line number, subroutine
              name, and source file corresponding to that position in the cur-
              rent  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] [--@@] [_d_i_r]
       ccdd --PP [--ee] [--@@] [_d_i_r]
              Change the current directory to _d_i_r.  if _d_i_r  is  not  supplied,
              the  value of the HHOOMMEE shell variable is used as _d_i_r.  The vari-
              able CCDDPPAATTHH exists, and _d_i_r does not begin with a slash (/),  ccdd
              uses it as a search path: the shell searches each directory name
              in  CCDDPPAATTHH  for  _d_i_r.  Alternative directory names in CCDDPPAATTHH are
              separated by a colon (:).  A null directory name  in  CCDDPPAATTHH  is
              the same as the current directory, i.e.,

              The  --PP option causes ccdd to use the physical directory structure
              by resolving symbolic links while traversing _d_i_r and before pro-
              cessing instances of _._. in _d_i_r (see also the --PP  option  to  the
              sseett builtin command).

              The  --LL  option  forces ccdd to follow symbolic links by resolving
              the link after processing instances of _._. in _d_i_r.  If _._. appears
              in _d_i_r, ccdd processes it by  removing  the  immediately  previous
              pathname component from _d_i_r, back to a slash or the beginning of
              _d_i_r,  and  verifying that the portion of _d_i_r it has processed to
              that point is still a valid directory name  after  removing  the
              pathname component.  If it is not a valid directory name, ccdd re-
              turns  a  non-zero status.  If neither --LL nor --PP is supplied, ccdd
              behaves as if --LL had been supplied.

              If the --ee option is supplied with --PP, and ccdd cannot successfully
              determine the current working directory after a  successful  di-
              rectory change, it returns a non-zero status.

              On  systems that support it, the --@@ option presents the extended
              attributes associated with a file as a directory.

              An argument of -- is converted to $$OOLLDDPPWWDD before  attempting  the
              directory change.

              If  ccdd  uses  a non-empty directory name from CCDDPPAATTHH, or if -- is
              the first argument, and the directory change is  successful,  ccdd
              writes the absolute pathname of the new working directory to the
              standard output.

              If  the directory change is successful, ccdd sets the value of the
              PPWWDD environment variable to the new directory name, and sets the
              OOLLDDPPWWDD environment variable to the value of the current  working
              directory before the change.

              The  return  value  is  true  if  the directory was successfully
              changed; false otherwise.

       ccoommmmaanndd [--ppVVvv] _c_o_m_m_a_n_d [_a_r_g ...]
              The ccoommmmaanndd builtin runs _c_o_m_m_a_n_d with _a_r_g_s suppressing the  nor-
              mal shell function lookup for _c_o_m_m_a_n_d.  Only builtin commands or
              commands  found  in the PPAATTHH named _c_o_m_m_a_n_d are executed.  If the
              --pp option is supplied, 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, ccoommmmaanndd prints a de-
              scription of _c_o_m_m_a_n_d.  The --vv option displays a single word  in-
              dicating  the command or filename used to invoke _c_o_m_m_a_n_d; the --VV
              option produces a more verbose description.

              If the --VV or --vv option is supplied, the exit status is  zero  if
              _c_o_m_m_a_n_d  was  found,  and non-zero if not.  If neither option is
              supplied and an error occurred or _c_o_m_m_a_n_d cannot be  found,  the
              exit  status  is 127.  Otherwise, the exit status of the ccoommmmaanndd
              builtin is the exit status of _c_o_m_m_a_n_d.

       ccoommppggeenn [--VV _v_a_r_n_a_m_e] [_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 exceptions of --pp, --rr, --DD, --EE, and --II, and write
              the matches to the standard output.

              If the --VV option is supplied, ccoommppggeenn stores the generated  com-
              pletions  into  the  indexed  array  variable _v_a_r_n_a_m_e instead of
              writing them to the standard output.

              When using the --FF or --CC options, the various shell variables set
              by the programmable completion facilities, while available, will
              not have useful values.

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

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

       ccoommpplleettee [--aabbccddeeffggjjkkssuuvv] [--oo _c_o_m_p_-_o_p_t_i_o_n] [--DDEEII] [--AA _a_c_t_i_o_n]
              [--GG _g_l_o_b_p_a_t] [--WW _w_o_r_d_l_i_s_t] [--FF _f_u_n_c_t_i_o_n] [--CC _c_o_m_m_a_n_d]
              [--XX _f_i_l_t_e_r_p_a_t] [--PP _p_r_e_f_i_x] [--SS _s_u_f_f_i_x] _n_a_m_e [_n_a_m_e ...]
       ccoommpplleettee --pprr [--DDEEII] [_n_a_m_e ...]
              Specify how arguments to each _n_a_m_e should be completed.

              If the --pp option is supplied, or if no options or _n_a_m_es are sup-
              plied,  print  existing  completion specifications in a way that
              allows them to be reused as input.  The --rr option removes a com-
              pletion specification for each _n_a_m_e, or, if no  _n_a_m_es  are  sup-
              plied, all completion specifications.

              The  --DD option indicates that other supplied options and actions
              should apply to the command completion; that is, completion  at-
              tempted on a command for which no completion has previously been
              defined.   The  --EE  option indicates that other supplied options
              and actions should apply to command completion; that is, comple-
              tion attempted on a blank line.  The --II  option  indicates  that
              other supplied options and actions should apply to completion on
              the  initial non-assignment word on the line, or after a command
              delimiter such as ;; or ||, which is usually command name  comple-
              tion.   If  multiple  options  are supplied, the --DD option takes
              precedence over --EE, and both take precedence over --II.  If any of
              --DD, --EE, or --II are supplied, any other  _n_a_m_e  arguments  are  ig-
              nored; these completions only apply to the case specified by the
              option.

              The process of applying these completion specifications when at-
              tempting word completion  is described in _b_a_s_h(1).

              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 rreeaaddlliinnee's default  filename  completion  if
                              the compspec generates no matches.
                      ddiirrnnaammeess
                              Perform  directory  name completion if the comp-
                              spec generates no matches.
                      ffiilleennaammeess
                              Tell rreeaaddlliinnee that the compspec generates  file-
                              names,  so  it can perform any filename-specific
                              processing (such as adding a slash to  directory
                              names,  quoting special characters, or suppress-
                              ing trailing spaces).  This is  intended  to  be
                              used with shell functions.
                      ffuullllqquuoottee
                              Tell  rreeaaddlliinnee  to quote all the completed words
                              even if they are not filenames.
                      nnooqquuoottee Tell rreeaaddlliinnee not to quote the  completed  words
                              if  they are filenames (quoting filenames is the
                              default).
                      nnoossoorrtt  Tell rreeaaddlliinnee not to sort the list  of  possible
                              completions alphabetically.
                      nnoossppaaccee Tell  rreeaaddlliinnee  not  to  append a space (the de-
                              fault) to words completed  at  the  end  of  the
                              line.
                      pplluussddiirrss
                              After  generating  any  matches  defined  by the
                              compspec, attempt directory name completion  and
                              add  any matches to the results of the other ac-
                              tions.
              --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  and directory names, similar to rreeaaddlliinnee's
                              filename completion.  May also be  specified  as
                              --ff.
                      ffuunnccttiioonn
                              Names of shell functions.
                      ggrroouupp   Group names.  May also be specified as --gg.
                      hheellppttooppiicc
                              Help topics as accepted by the hheellpp builtin.
                      hhoossttnnaammee
                              Hostnames,  as  taken from the file specified by
                              the HHOOSSTTFFIILLEE shell variable.
                      jjoobb     Job names, if job control is active.   May  also
                              be specified as --jj.
                      kkeeyywwoorrdd Shell  reserved words.  May also be specified as
                              --kk.
                      rruunnnniinngg Names of running jobs, if job control is active.
                      sseerrvviiccee Service names.  May also be specified as --ss.
                      sseettoopptt  Valid arguments for the --oo  option  to  the  sseett
                              builtin.
                      sshhoopptt   Shell  option  names  as  accepted  by the sshhoopptt
                              builtin.
                      ssiiggnnaall  Signal names.
                      ssttooppppeedd Names of stopped jobs, if job control is active.
                      uusseerr    User names.  May also be specified as --uu.
                      vvaarriiaabbllee
                              Names of all shell variables.  May also be spec-
                              ified as --vv.
              --CC _c_o_m_m_a_n_d
                      _c_o_m_m_a_n_d is executed in a subshell environment,  and  its
                      output  is  used as the possible completions.  Arguments
                      are passed as with the --FF option.
              --FF _f_u_n_c_t_i_o_n
                      The shell function _f_u_n_c_t_i_o_n is executed in  the  current
                      shell  environment.   When the function is executed, the
                      first argument ($$11) is the name of the command whose ar-
                      guments are being completed, the second argument ($$22) is
                      the word being completed, and the third argument ($$33) is
                      the word preceding the word being completed on the  cur-
                      rent command line.  When _f_u_n_c_t_i_o_n finishes, programmable
                      completion  retrieves  the possible completions from the
                      value of the CCOOMMPPRREEPPLLYY array variable.
              --GG _g_l_o_b_p_a_t
                      Expand the pathname expansion pattern _g_l_o_b_p_a_t to  gener-
                      ate the possible completions.
              --PP _p_r_e_f_i_x
                      Add  _p_r_e_f_i_x to the beginning of each possible completion
                      after all other options have been applied.
              --SS _s_u_f_f_i_x
                      Append _s_u_f_f_i_x to  each  possible  completion  after  all
                      other options have been applied.
              --WW _w_o_r_d_l_i_s_t
                      Split  the _w_o_r_d_l_i_s_t using the characters in the IIFFSS spe-
                      cial variable as delimiters, and expand  each  resulting
                      word.   Shell quoting is honored within _w_o_r_d_l_i_s_t, in or-
                      der to provide a mechanism  for  the  words  to  contain
                      shell  metacharacters or characters in the value of IIFFSS.
                      The possible completions are the members of  the  resul-
                      tant  list  which  match a prefix of the word being com-
                      pleted.
              --XX _f_i_l_t_e_r_p_a_t
                      _f_i_l_t_e_r_p_a_t is a pattern as used for  pathname  expansion.
                      It is applied to the list of possible completions gener-
                      ated  by  the  preceding options and arguments, and each
                      completion matching _f_i_l_t_e_r_p_a_t is removed from the  list.
                      A  leading  !!  in _f_i_l_t_e_r_p_a_t negates the pattern; in this
                      case, any completion not matching _f_i_l_t_e_r_p_a_t is removed.

              The return value is true unless an invalid option  is  supplied,
              an option other than --pp, --rr, --DD, --EE, or --II is supplied without a
              _n_a_m_e  argument, an attempt is made to remove a completion speci-
              fication for a _n_a_m_e for which no specification exists, or an er-
              ror occurs adding a completion specification.

       ccoommppoopptt [--oo _o_p_t_i_o_n] [--DDEEII] [++oo _o_p_t_i_o_n] [_n_a_m_e]
              Modify completion options for each _n_a_m_e  according  to  the  _o_p_-
              _t_i_o_ns, or for the currently-executing completion if no _n_a_m_es are
              supplied.   If  no  _o_p_t_i_o_ns are supplied, 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 de-
              scribed above.

              The --DD option indicates that other supplied options should apply
              to the command completion; the --EE option  indicates  that  other
              supplied  options should apply to command completion; and the --II
              option indicates that other supplied  options  should  apply  to
              completion  on  the  initial word on the line.  These are deter-
              mined in the same way as the ccoommpplleettee builtin.

              If multiple options are supplied, the --DD option takes precedence
              over --EE, and both take precedence over --II.

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

       ccoonnttiinnuuee [_n]
              ccoonnttiinnuuee resumes the next iteration of the enclosing ffoorr, wwhhiillee,
              uunnttiill,  or sseelleecctt loop.  If _n is specified, bbaasshh resumes the _nth
              enclosing loop.  _n must be >= 1.  If _n is greater than the  num-
              ber  of  enclosing  loops,  the shell resumes the last enclosing
              loop (the loop).  The return value is 0 unless _n is not  greater
              than or equal to 1.

       ddeeccllaarree [--aaAAffFFggiiIIllnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...]
       ttyyppeesseett [--aaAAffFFggiiIIllnnrrttuuxx] [--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 or functions.  The --pp
              option will display the attributes  and  values  of  each  _n_a_m_e.
              When  --pp  is used with _n_a_m_e arguments, additional options, other
              than --ff and --FF, are ignored.

              When --pp is supplied without _n_a_m_e arguments, ddeeccllaarree 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 restricts the display to
              shell functions.

              The --FF option inhibits the display of function definitions; only
              the function name and attributes are printed.  If  the  eexxttddeebbuugg
              shell  option  is  enabled using sshhoopptt, the source file name and
              line number where each _n_a_m_e is defined are  displayed  as  well.
              The --FF option implies --ff.

              The  --gg option forces variables to be created or modified at the
              global scope, even when ddeeccllaarree is executed in a shell function.
              It is ignored when ddeeccllaarree is not executed in a shell function.

              The --II option causes local variables to inherit  the  attributes
              (except  the  _n_a_m_e_r_e_f attribute) and value of any existing vari-
              able with the same _n_a_m_e at a surrounding scope.  If there is  no
              existing variable, the local variable is initially unset.

              The  following  options  can be used to restrict output to vari-
              ables with the specified attribute or to give variables  attrib-
              utes:
              --aa     Each  _n_a_m_e  is  an  indexed array variable (see AArrrraayyss in
                     _b_a_s_h(1)).
              --AA     Each _n_a_m_e is an associative array variable (see AArrrraayyss in
                     _b_a_s_h(1)).
              --ff     Each _n_a_m_e refers to a shell function.
              --ii     The variable is treated as an integer; arithmetic evalua-
                     tion (see AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN in _b_a_s_h(1)) is  performed
                     when the variable is assigned a value.
              --ll     When  the  variable  is  assigned a value, all upper-case
                     characters are converted to lower-case.   The  upper-case
                     attribute is disabled.
              --nn     Give  each  _n_a_m_e  the _n_a_m_e_r_e_f attribute, making it a name
                     reference to another variable.  That  other  variable  is
                     defined  by  the  value of _n_a_m_e.  All references, assign-
                     ments, and attribute modifications to _n_a_m_e, except  those
                     using  or changing the --nn attribute itself, are performed
                     on the variable referenced by _n_a_m_e's value.  The  nameref
                     attribute cannot be applied to array variables.
              --rr     Make _n_a_m_es readonly.  These names cannot then be assigned
                     values by subsequent assignment statements or unset.
              --tt     Give each _n_a_m_e the _t_r_a_c_e attribute.  Traced functions in-
                     herit  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 each _n_a_m_e for export to subsequent commands via  the
                     environment.

              Using instead of turns off the specified attribute instead, with
              the  exceptions  that ++aa and ++AA may not be used to destroy array
              variables and ++rr will not remove the readonly attribute.

              When used in a function, ddeeccllaarree and ttyyppeesseett make each _n_a_m_e  lo-
              cal,  as  with  the  llooccaall command, unless the --gg option is sup-
              plied.  If a variable name is followed by =_v_a_l_u_e, the  value  of
              the  variable is set to _v_a_l_u_e.  When using --aa or --AA and the com-
              pound assignment syntax to create  array  variables,  additional
              attributes do not take effect until subsequent assignments.

              The  return  value is 0 unless an invalid option is encountered,
              an attempt is made to define a function using 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 in _b_a_s_h(1)), 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 readonly variable, an attempt is  made  to
              turn  off  array  status for an array variable, or an attempt is
              made to display a non-existent function with --ff.

       ddiirrss [[--ccllppvv]] [[++_n]] [[--_n]]
              Without options, display the list of currently remembered direc-
              tories.  The default display is on a single line with  directory
              names  separated  by  spaces.  Directories are added to the list
              with the ppuusshhdd command; the ppooppdd command  removes  entries  from
              the  list.   The current directory is always the first directory
              in the stack.

              Options, if supplied, have the following meanings:
              --cc     Clears the directory stack by deleting  all  of  the  en-
                     tries.
              --ll     Produces  a  listing  using  full  pathnames; the default
                     listing format uses a tilde to denote the home directory.
              --pp     Print the directory stack with one entry per line.
              --vv     Print the directory stack with one entry per  line,  pre-
                     fixing each entry with its index in the stack.
              ++_n     Displays the _nth entry counting from the left of the list
                     shown by ddiirrss when invoked without options, starting with
                     zero.
              --_n     Displays  the  _nth  entry  counting from the right of the
                     list shown by ddiirrss when invoked without options, starting
                     with zero.

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

       ddiissoowwnn [--aarr] [--hh] [_i_d ...]
              Without  options,  remove each _i_d from the table of active jobs.
              Each _i_d may be a job specification _j_o_b_s_p_e_c or a process ID  _p_i_d;
              if _i_d is a _p_i_d, ddiissoowwnn uses the job containing _p_i_d as _j_o_b_s_p_e_c.

              If  the  --hh  option is supplied, ddiissoowwnn does not remove the jobs
              corresponding to each _i_d from the jobs table, but  rather  marks
              them  so  the shell does not send SSIIGGHHUUPP to the job if the shell
              receives a SSIIGGHHUUPP.

              If no _i_d is supplied, the --aa option means to remove or mark  all
              jobs; the --rr option without an _i_d argument removes or marks run-
              ning  jobs.  If no _i_d is supplied, and neither the --aa nor the --rr
              option is supplied, ddiissoowwnn removes or marks the current job.

              The return value is 0 unless an _i_d does not specify a valid job.

       eecchhoo [--nneeEE] [_a_r_g ...]
              Output the _a_r_gs, separated by spaces,  followed  by  a  newline.
              The  return  status  is 0 unless a write error occurs.  If --nn is
              specified, the trailing newline is not printed.

              If the --ee option is given, eecchhoo interprets the  following  back-
              slash-escaped characters.  The --EE option disables interpretation
              of  these  escape characters, even on systems where they are in-
              terpreted by default.   The  xxppgg__eecchhoo  shell  option  determines
              whether or not eecchhoo interprets any options and expands these es-
              cape  characters.  eecchhoo does not interpret ---- to mean the end of
              options.

              eecchhoo interprets the following escape sequences:
              \\aa     alert (bell)
              \\bb     backspace
              \\cc     suppress further output
              \\ee
              \\EE     an escape character
              \\ff     form feed
              \\nn     new line
              \\rr     carriage return
              \\tt     horizontal tab
              \\vv     vertical tab
              \\\\     backslash
              \\00_n_n_n  The eight-bit character whose value is  the  octal  value
                     _n_n_n (zero to three octal digits).
              \\xx_H_H   The  eight-bit  character  whose value is the hexadecimal
                     value _H_H (one or two hex digits).
              \\uu_H_H_H_H The Unicode (ISO/IEC 10646) character whose value is  the
                     hexadecimal value _H_H_H_H (one to four hex digits).
              \\UU_H_H_H_H_H_H_H_H
                     The  Unicode (ISO/IEC 10646) character whose value is the
                     hexadecimal value _H_H_H_H_H_H_H_H (one to eight hex digits).

              eecchhoo writes any unrecognized  backslash-escaped  characters  un-
              changed.

       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 an executable file 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 files.

              If --nn is supplied, each _n_a_m_e is disabled; otherwise,  _n_a_m_es  are
              enabled.   For  example, to use the tteesstt binary found using PPAATTHH
              instead of the shell builtin version, run

              If no _n_a_m_e arguments are supplied, or if the --pp option  is  sup-
              plied, print a list of shell builtins.  With no other option ar-
              guments, the list consists of all enabled shell builtins.  If --nn
              is  supplied,  print only disabled builtins.  If --aa is supplied,
              the list printed includes all builtins, with  an  indication  of
              whether or not each is enabled.  The --ss option means to restrict
              the output to the POSIX _s_p_e_c_i_a_l builtins.

              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.
              If _f_i_l_e_n_a_m_e does not contain a slash, BBaasshh will use the value of
              the BBAASSHH__LLOOAADDAABBLLEESS__PPAATTHH variable as a  colon-separated  list  of
              directories  in  which  to search for _f_i_l_e_n_a_m_e.  The default for
              BBAASSHH__LLOOAADDAABBLLEESS__PPAATTHH is  system-dependent,  and  may  include  to
              force  a  search  of  the current directory.  The --dd option will
              delete a builtin previously loaded with --ff.  If _-_s is used  with
              _-_f, the new builtin becomes a POSIX special builtin.

              If  no  options  are supplied and a _n_a_m_e is not a shell builtin,
              eennaabbllee will attempt to load _n_a_m_e  from  a  shared  object  named
              _n_a_m_e, as if the command were

              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 ...]
              Concatenate the _a_r_gs together into a single command,  separating
              them with spaces.  BBaasshh then reads and execute this command, and
              returns  its exit status as the return status 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 without  creating
              a  new  process.  _c_o_m_m_a_n_d cannot be a shell builtin or function.
              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 beginning of the ze-
              roth 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 envi-
              ronment.  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 cannot be executed for some reason, a non-interactive
              shell exits, unless the eexxeeccffaaiill shell option  is  enabled.   In
              that  case,  it returns a non-zero status.  An interactive shell
              returns a non-zero status if the file  cannot  be  executed.   A
              subshell exits unconditionally if eexxeecc fails.

              If _c_o_m_m_a_n_d is not specified, any redirections take effect in the
              current  shell, and the return status is 0.  If there is a redi-
              rection 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.  Any trap
              on EEXXIITT is executed before the shell terminates.

       eexxppoorrtt [--ffnn] [_n_a_m_e[=_v_a_l_u_e]] ...
       eexxppoorrtt --pp [[--ff]]
              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.

              The --nn option unexports, or removes the export  attribute,  from
              each  _n_a_m_e.   If no _n_a_m_e_s are given, or if only the --pp option is
              supplied, eexxppoorrtt displays a list of names of all exported  vari-
              ables on the standard output.  Using --pp and --ff together displays
              exported  functions.   The  --pp  option displays output in a form
              that may be reused as input.

              eexxppoorrtt allows the value of a variable to be set when it  is  ex-
              ported or unexported by following the variable name with =_v_a_l_u_e.
              This sets the value of the variable to _v_a_l_u_e while modifying the
              export  attribute.  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
              function.

       ffaallssee  Does nothing; returns a non-zero status.

       ffcc [--ee _e_n_a_m_e] [--llnnrr] [_f_i_r_s_t] [_l_a_s_t]
       ffcc --ss [_p_a_t=_r_e_p] [_c_m_d]
              The  first  form  selects a range of commands from _f_i_r_s_t to _l_a_s_t
              from the history list and  displays  or  edits  and  re-executes
              them.   _F_i_r_s_t  and  _l_a_s_t may be specified as a string (to locate
              the last command beginning with that string) or as a number  (an
              index  into the history list, where a negative number is used as
              an offset from the current command number).

              When listing, a _f_i_r_s_t or _l_a_s_t of 0 is equivalent to -1 and -0 is
              equivalent to the current command (usually the ffcc command); oth-
              erwise 0 is equivalent to -1 and -0 is invalid.  If _l_a_s_t is  not
              specified, it is set to the current command for listing (so that
              prints  the  last 10 commands) and to _f_i_r_s_t otherwise.  If _f_i_r_s_t
              is not specified, it is set to the previous command for  editing
              and -16 for listing.

              If  the  --ll  option  is supplied, the commands are listed on the
              standard output.  The --nn option suppresses the  command  numbers
              when listing.  The --rr option reverses the order of the commands.

              Otherwise,  ffcc  invokes the editor named by _e_n_a_m_e on a file con-
              taining those commands.  If _e_n_a_m_e is not supplied, ffcc  uses  the
              value  of the FFCCEEDDIITT variable, and the value of EEDDIITTOORR if FFCCEEDDIITT
              is not set.  If neither variable is set, ffcc uses _v_i_. When  edit-
              ing  is  complete,  ffcc reads the file containing the edited com-
              mands and echoes and executes them.

              In the second form, ffcc re-executes _c_o_m_m_a_n_d after replacing  each
              instance  of  _p_a_t  with _r_e_p.  _C_o_m_m_a_n_d is interpreted the same as
              _f_i_r_s_t above.

              A useful alias to use with ffcc is so that typing  runs  the  last
              command beginning with and typing re-executes the last command.

              If  the  first  form is used, the return value is zero unless an
              invalid option is encountered or _f_i_r_s_t or _l_a_s_t  specify  history
              lines  out  of  range.   When editing and re-executing a file of
              commands, the return value is the value of the last command exe-
              cuted or failure if an error occurs with the temporary file.  If
              the second form is used, the return status is that of the re-ex-
              ecuted command, unless _c_m_d does not specify a valid history  en-
              try, in which case ffcc returns a non-zero status.

       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, ffgg uses the  shell's  notion  of  the
              _c_u_r_r_e_n_t  _j_o_b.   The  return  value is that of the command placed
              into the foreground, or failure if run when job control is  dis-
              abled or, when run with job control enabled, if _j_o_b_s_p_e_c does not
              specify  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 ...]
              ggeettooppttss is used by shell scripts and functions  to  parse  posi-
              tional  parameters and obtain options and their arguments.  _o_p_t_-
              _s_t_r_i_n_g contains the option characters to  be  recognized;  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 automatically; it must be manu-
              ally reset between multiple calls to  ggeettooppttss  within  the  same
              shell invocation to use a new set of parameters.

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

              ggeettooppttss  normally  parses the positional parameters, but if more
              arguments are supplied as _a_r_g values, ggeettooppttss parses  those  in-
              stead.

              ggeettooppttss  can  report errors in two ways.  If the first character
              of _o_p_t_s_t_r_i_n_g is a colon, ggeettooppttss uses  _s_i_l_e_n_t  error  reporting.
              In  normal operation, ggeettooppttss prints diagnostic messages when it
              encounters invalid options or missing option arguments.  If  the
              variable  OOPPTTEERRRR is set to 0, ggeettooppttss does not display any error
              messages, even if the first character  of  _o_p_t_s_t_r_i_n_g  is  not  a
              colon.

              If ggeettooppttss detects an invalid option, it places ? into _n_a_m_e and,
              if  not  silent,  prints an error message and unsets OOPPTTAARRGG.  If
              ggeettooppttss is silent, it assigns the option character found to  OOPP--
              TTAARRGG and does not print a diagnostic message.

              If  a required argument is not found, and ggeettooppttss is not silent,
              it sets the value of _n_a_m_e to a question mark (??), unsets OOPPTTAARRGG,
              and prints a diagnostic message.  If ggeettooppttss is silent, it  sets
              the  value  of _n_a_m_e to a colon (::) and sets OOPPTTAARRGG to the option
              character found.

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

       hhaasshh [--llrr] [--pp _f_i_l_e_n_a_m_e] [--ddtt] [_n_a_m_e]
              Each time hhaasshh is invoked, it remembers the full pathname of the
              command  _n_a_m_e  as  determined  by  searching  the directories in
              $$PPAATTHH.  Any previously-remembered pathname associated with  _n_a_m_e
              is  discarded.  If the --pp option is supplied, hhaasshh uses _f_i_l_e_n_a_m_e
              as the full pathname of the command.

              The --rr option causes the shell to forget  all  remembered  loca-
              tions.   Assigning  to  the PPAATTHH variable also clears all hashed
              filenames.  The --dd option causes the shell to forget the  remem-
              bered location of each _n_a_m_e.

              If the --tt option is supplied, hhaasshh prints the full pathname cor-
              responding  to  each  _n_a_m_e.  If multiple _n_a_m_e arguments are sup-
              plied with --tt, hhaasshh prints the  _n_a_m_e  before  the  corresponding
              hashed full pathname.  The --ll option displays output in a format
              that may be reused as input.

              If  no  arguments  are  given,  or  if only --ll is supplied, hhaasshh
              prints information about remembered commands.  The --tt,  --dd,  and
              --pp  options (the options that act on the _n_a_m_e arguments) are mu-
              tually exclusive.  Only one will be active.  If more than one is
              supplied, --tt has higher priority than --pp, and both  have  higher
              priority than --dd.

              The  return  status is zero unless a _n_a_m_e is not found or an in-
              valid 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 as described below; otherwise it displays a list of  all
              the builtins and shell compound commands.

              Options, if supplied, have the follow meanings:

              --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

              If  _p_a_t_t_e_r_n  contains  pattern  matching characters (see PPaatttteerrnn
              MMaattcchhiinngg above) it's treated as a shell pattern and hheellpp  prints
              the description of each help topic matching _p_a_t_t_e_r_n.

              If  not,  and  _p_a_t_t_e_r_n exactly matches the name of a help topic,
              hheellpp prints the description associated with that topic.   Other-
              wise,  hheellpp performs prefix matching and prints the descriptions
              of all matching help topics.

              The return status is 0 unless no command matches _p_a_t_t_e_r_n.

       hhiissttoorryy [[_n]]
       hhiissttoorryy --cc
       hhiissttoorryy --dd _o_f_f_s_e_t
       hhiissttoorryy --dd _s_t_a_r_t-_e_n_d
       hhiissttoorryy --aannrrww [_f_i_l_e_n_a_m_e]
       hhiissttoorryy --pp _a_r_g [_a_r_g ...]
       hhiissttoorryy --ss _a_r_g [_a_r_g ...]
              With no options, display the command history list with  numbers.
              Entries  prefixed with a ** have been modified.  An argument of _n
              lists only the last _n entries.  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.  If hhiissttoorryy uses HHIISSTTTTIIMMEEFFOORRMMAATT, it does
              not print an intervening space between the formatted time  stamp
              and the history entry.

              If _f_i_l_e_n_a_m_e is supplied, hhiissttoorryy uses it as the name of the his-
              tory  file;  if not, it uses the value of HHIISSTTFFIILLEE.  If _f_i_l_e_n_a_m_e
              is not supplied and HHIISSTTFFIILLEE is unset or null, the --aa,,  --nn,,  --rr,,
              and --ww options have no effect.

              Options, if supplied, have the following meanings:
              --cc     Clear the history list by deleting all the entries.  This
                     can be used with the other options to replace the history
                     list.
              --dd _o_f_f_s_e_t
                     Delete  the  history entry at position _o_f_f_s_e_t.  If _o_f_f_s_e_t
                     is negative, it is interpreted as relative to one greater
                     than the last history position, so negative indices count
                     back from the end of the history,  and  an  index  of  -1
                     refers to the current hhiissttoorryy --dd command.
              --dd _s_t_a_r_t-_e_n_d
                     Delete  the  range  of  history entries between positions
                     _s_t_a_r_t and _e_n_d, inclusive.  Positive and  negative  values
                     for _s_t_a_r_t and _e_n_d are interpreted as described above.
              --aa     Append  the history lines to the history file.  These are
                     history lines entered since the beginning of the  current
                     bbaasshh  session,  but  not  already appended to the history
                     file.
              --nn     Read the history lines not already read from the  history
                     file and add them to the current history list.  These are
                     lines appended to the history file since the beginning of
                     the current bbaasshh session.
              --rr     Read the history file and append its contents to the cur-
                     rent history list.
              --ww     Write the current history list to the history file, over-
                     writing the history file.
              --pp     Perform  history  substitution  on the following _a_r_g_s and
                     display the result on the standard output, without  stor-
                     ing  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
                     adding the _a_r_g_s.

              If the HHIISSTTTTIIMMEEFFOORRMMAATT variable is set, hhiissttoorryy writes  the  time
              stamp information associated with each history entry to the his-
              tory  file,  marked  with  the  history comment character as de-
              scribed above.  When the history file is read,  lines  beginning
              with  the  history  comment  character followed immediately by a
              digit are interpreted as timestamps for  the  following  history
              entry.

              The  return  value is 0 unless an invalid option is encountered,
              an error occurs while reading or writing the  history  file,  an
              invalid _o_f_f_s_e_t or range 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.
              --nn     Display  information  only  about  jobs that have changed
                     status since the user was last notified of their status.
              --pp     List only the process  ID  of  the  job's  process  group
                     leader.
              --rr     Display only running jobs.
              --ss     Display only stopped jobs.

              If  _j_o_b_s_p_e_c  is  supplied,  jjoobbss restricts output 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 ex-
              ecutes _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] _i_d [ ... ]
       kkiillll --ll|--LL [_s_i_g_s_p_e_c | _e_x_i_t___s_t_a_t_u_s]
              Send the signal specified by _s_i_g_s_p_e_c or _s_i_g_n_u_m to the  processes
              named by each _i_d.  Each _i_d may be a job specification _j_o_b_s_p_e_c or
              a  process  ID _p_i_d.  _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  sig-
              nal  number;  _s_i_g_n_u_m is a signal number.  If _s_i_g_s_p_e_c is not sup-
              plied, then kkiillll sends SSIIGGTTEERRMM.

              The --ll option lists the signal names.  If any arguments are sup-
              plied when --ll is given, kkiillll lists the names of the signals cor-
              responding to the arguments, 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 sig-
              nal number or the exit status of a process terminated by a  sig-
              nal;  if it is supplied, kkiillll prints the name of the signal that
              caused the process to terminate.  kkiillll assumes that process exit
              statuses are greater than 128; anything less than that is a sig-
              nal number.  The --LL option is equivalent to --ll.

              kkiillll returns true if at least one signal was successfully  sent,
              or false if an error occurs or an invalid option is encountered.

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

       llooccaall [_o_p_t_i_o_n] [_n_a_m_e[=_v_a_l_u_e] ... | - ]
              For each argument, create a local variable named _n_a_m_e and assign
              it  _v_a_l_u_e.  The _o_p_t_i_o_n can be any of the options accepted by ddee--
              ccllaarree.  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.  It is an error to  use  llooccaall  when  not
              within a function.

              If  _n_a_m_e  is  -,  it makes the set of shell options local to the
              function in which llooccaall is invoked: any  shell  options  changed
              using  the sseett builtin inside the function after the call to lloo--
              ccaall are restored to their original values when the function  re-
              turns.   The restore is performed as if a series of sseett commands
              were executed to restore the values that were  in  place  before
              the function.

              With  no operands, llooccaall writes a list of local variables to the
              standard output.

              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 [[_n]]
              Exit  a login shell, returning a status of _n to the shell's par-
              ent.

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

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

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

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

       ppooppdd [-nn] [+_n] [-_n]
              Remove  entries from the directory stack.  The elements are num-
              bered from 0 starting at the first directory listed by ddiirrss,  so
              ppooppdd  is  equivalent  to With no arguments, ppooppdd removes the top
              directory from the stack, and changes to the new top  directory.
              Arguments, if supplied, have the following meanings:
              --nn     Suppress the normal change of directory when removing di-
                     rectories from the stack, only manipulate the stack.
              ++_n     Remove  the  _nth entry counting from the left of the list
                     shown by ddiirrss, starting with zero, from the  stack.   For
                     example: removes the first directory, the second.
              --_n     Remove  the _nth entry counting from the right of the list
                     shown by ddiirrss, starting with zero.  For example:  removes
                     the last directory, the next to last.

              If  the  top element of the directory stack is modified, and the
              _-_n option was not supplied, ppooppdd uses the ccdd builtin  to  change
              to the directory at the top of the stack.  If the ccdd fails, ppooppdd
              returns a non-zero value.

              Otherwise,  ppooppdd returns false if an invalid option is supplied,
              the directory stack is empty, or _n specifies a non-existent  di-
              rectory stack entry.

              If  the  ppooppdd  command is successful, bbaasshh runs ddiirrss to show the
              final contents of the directory stack, and the return status  is
              0.

       pprriinnttff [--vv _v_a_r] _f_o_r_m_a_t [_a_r_g_u_m_e_n_t_s]
              Write  the  formatted _a_r_g_u_m_e_n_t_s to the standard output under the
              control of the _f_o_r_m_a_t.  The --vv option assigns the output to  the
              variable _v_a_r rather than printing it to the standard output.

              The  _f_o_r_m_a_t  is a character string which contains three types of
              objects: plain characters, which are simply copied  to  standard
              output,  character  escape  sequences,  which  are converted and
              copied to the standard output, and format  specifications,  each
              of  which  causes  printing of the next successive _a_r_g_u_m_e_n_t.  In
              addition to  the  standard  _p_r_i_n_t_f(3)  format  characters  ccCCssSS--
              nnddiioouuxxXXeeEEffFFggGGaaAA, pprriinnttff interprets the following additional for-
              mat specifiers:
              %%bb     causes pprriinnttff to expand backslash escape sequences in the
                     corresponding _a_r_g_u_m_e_n_t in the same way as eecchhoo --ee.
              %%qq     causes  pprriinnttff  to output the corresponding _a_r_g_u_m_e_n_t in a
                     format that can be reused as shell input.  %%qq and %%QQ  use
                     the  $$  quoting  style  if any characters in the argument
                     string require it, and backslash quoting  otherwise.   If
                     the  format  string uses the _p_r_i_n_t_f alternate form, these
                     two  formats  quote  the  argument  string  using  single
                     quotes.
              %%QQ     like  %%qq, but applies any supplied precision to the _a_r_g_u_-
                     _m_e_n_t before quoting it.
              %%((_d_a_t_e_f_m_t))TT
                     causes pprriinnttff to output the  date-time  string  resulting
                     from  using  _d_a_t_e_f_m_t  as a format string for _s_t_r_f_t_i_m_e(3).
                     The corresponding _a_r_g_u_m_e_n_t is an integer representing the
                     number of seconds since the epoch.  This format specifier
                     recognizes two special argument values: -1 represents the
                     current time, and -2 represents the time  the  shell  was
                     invoked.  If no argument is specified, conversion behaves
                     as  if -1 had been supplied.  This is an exception to the
                     usual pprriinnttff behavior.

              The %b, %q, and %T format specifiers all use the field width and
              precision arguments from the format specification and write that
              many bytes from (or use that wide a field for) the expanded  ar-
              gument,  which  usually contains more characters than the origi-
              nal.

              The %n format specifier accepts a corresponding argument that is
              treated as a shell variable name.

              The %s and %c format specifiers accept  an  l  (long)  modifier,
              which forces them to convert the argument string to a wide-char-
              acter string and apply any supplied field width and precision in
              terms of characters, not bytes.  The %S and %C format specifiers
              are equivalent to %ls and %lc, respectively.

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

              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 if an invalid option is sup-
              plied or a write or assignment error occurs.

       ppuusshhdd [--nn] [+_n] [-_n]
       ppuusshhdd [--nn] [_d_i_r]
              Add a directory to the top of the directory stack, or rotate the
              stack, making the new top of the stack the current  working  di-
              rectory.   With  no  arguments, ppuusshhdd exchanges the top two ele-
              ments of the directory stack.  Arguments, if supplied, have  the
              following meanings:
              --nn     Suppress  the normal change of directory when rotating or
                     adding directories to  the  stack,  only  manipulate  the
                     stack.
              ++_n     Rotate 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.

              After the stack has been modified, if the --nn option was not sup-
              plied, ppuusshhdd uses the ccdd builtin to change to the  directory  at
              the top of the stack.  If the ccdd fails, ppuusshhdd returns a non-zero
              value.

              Otherwise,  if no arguments are supplied, ppuusshhdd returns zero un-
              less the directory stack is empty.  When rotating the  directory
              stack, ppuusshhdd returns zero unless the directory stack is empty or
              _n specifies a non-existent directory stack element.

              If  the  ppuusshhdd command is successful, bbaasshh runs ddiirrss to show the
              final contents of the directory stack.

       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 in-
              valid option is supplied.

       rreeaadd [--EEeerrss] [--aa _a_n_a_m_e] [--dd _d_e_l_i_m] [--ii _t_e_x_t] [--nn _n_c_h_a_r_s] [--NN _n_c_h_a_r_s]
       [--pp _p_r_o_m_p_t] [--tt _t_i_m_e_o_u_t] [--uu _f_d] [_n_a_m_e ...]
              Read one line from the standard input, or from the file descrip-
              tor  _f_d  supplied as an argument to the --uu option, split it into
              words as described in _b_a_s_h (1) under WWoorrdd SSpplliittttiinngg, and  assign
              the  first word to the first _n_a_m_e, the second word to the second
              _n_a_m_e, and so on.  If there are more words than  names,  the  re-
              maining  words  and their intervening delimiters are assigned to
              the last _n_a_m_e.  If there are fewer words  read  from  the  input
              stream  than  names, the remaining names are assigned empty val-
              ues.  The characters in the value of the IIFFSS variable  are  used
              to split the line into words using the same rules the shell uses
              for expansion (described in _b_a_s_h (1) under WWoorrdd SSpplliittttiinngg).  The
              backslash character (\\) removes any special meaning for the next
              character read and is used for line continuation.

              Options, if supplied, have the following meanings:
              --aa _a_n_a_m_e
                     The words are assigned to sequential indices of the array
                     variable _a_n_a_m_e, starting at 0.  _a_n_a_m_e is unset before any
                     new  values  are  assigned.  Other _n_a_m_e arguments are ig-
                     nored.
              --dd _d_e_l_i_m
                     The first character of _d_e_l_i_m terminates the  input  line,
                     rather  than newline.  If _d_e_l_i_m is the empty string, rreeaadd
                     will terminate a line when it reads a NUL character.
              --ee     If the standard input is coming  from  a  terminal,  rreeaadd
                     uses  rreeaaddlliinnee  (see  RREEAADDLLIINNEE  in _b_a_s_h(1)) to obtain the
                     line.  RReeaaddlliinnee uses the current  (or  default,  if  line
                     editing  was not previously active) editing settings, but
                     uses rreeaaddlliinnee's default filename completion.
              --EE     If the standard input is coming  from  a  terminal,  rreeaadd
                     uses  rreeaaddlliinnee  (see  RREEAADDLLIINNEE  in _b_a_s_h(1)) to obtain the
                     line.  RReeaaddlliinnee uses the current  (or  default,  if  line
                     editing  was not previously active) editing settings, but
                     uses bash's default  completion,  including  programmable
                     completion.
              --ii _t_e_x_t
                     If  rreeaaddlliinnee  is being used to read the line, rreeaadd places
                     _t_e_x_t 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, unless it encoun-
                     ters EOF or rreeaadd times out, but honors a delimiter if  it
                     reads fewer than _n_c_h_a_r_s characters before the delimiter.
              --NN _n_c_h_a_r_s
                     rreeaadd  returns  after  reading  exactly  _n_c_h_a_r_s characters
                     rather than waiting for a complete line of input,  unless
                     it encounters EOF or rreeaadd times out.  Any delimiter char-
                     acters  in the input are not treated specially and do not
                     cause rreeaadd to return until it has read _n_c_h_a_r_s characters.
                     The result is not split on the characters in IIFFSS; the in-
                     tent is that the variable is assigned exactly the charac-
                     ters read (with the exception of backslash;  see  the  --rr
                     option below).
              --pp _p_r_o_m_p_t
                     Display _p_r_o_m_p_t on standard error, without a trailing new-
                     line,  before  attempting  to read any input, but only if
                     input is coming from a terminal.
              --rr     Backslash does not act as an escape character.  The back-
                     slash is considered to be part of the line.  In  particu-
                     lar,  a  backslash-newline pair may not then be used as a
                     line continuation.
              --ss     Silent mode.  If input is coming from a terminal, charac-
                     ters are not echoed.
              --tt _t_i_m_e_o_u_t
                     Cause rreeaadd to time out and return failure if it does  not
                     read  a  complete line of input (or a specified number of
                     characters) 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 effective if rreeaadd  is
                     reading  input  from  a  terminal, pipe, or other special
                     file; it has no effect when reading from  regular  files.
                     If  rreeaadd  times out, it saves any partial input read into
                     the specified variable  _n_a_m_e,  and  the  exit  status  is
                     greater  than 128.  If _t_i_m_e_o_u_t is 0, rreeaadd returns immedi-
                     ately, without trying to read any data.   In  this  case,
                     the  exit status is 0 if input is available on the speci-
                     fied file descriptor, or the read will return  EOF,  non-
                     zero otherwise.
              --uu _f_d  Read  input  from file descriptor _f_d instead of the stan-
                     dard input.

              Other than the case where _d_e_l_i_m is the empty  string,  rreeaadd  ig-
              nores any NUL characters in the input.

              If  no  _n_a_m_e_s  are supplied, rreeaadd assigns the line read, without
              the ending delimiter but otherwise unmodified, to  the  variable
              RREEPPLLYY.

              The exit status is zero, unless end-of-file is encountered, rreeaadd
              times  out  (in  which  case  the status is greater than 128), a
              variable assignment error (such as assigning to a readonly vari-
              able) occurs, or an invalid file descriptor is supplied  as  the
              argument to --uu.

       rreeaaddoonnllyy [--aaAAff] [--pp] [_n_a_m_e[=_w_o_r_d] ...]
              The  given  _n_a_m_e_s are marked readonly; the values of these _n_a_m_e_s
              may not be changed by subsequent assignment or unset.  If the --ff
              option is supplied, each _n_a_m_e refers to a shell  function.   The
              --aa  option restricts the variables to indexed arrays; the --AA op-
              tion restricts the variables to associative arrays.  If both op-
              tions are supplied, --AA takes precedence.  If no  _n_a_m_e  arguments
              are  supplied,  or if the --pp option is supplied, print a list of
              all readonly names.  The other options may be used  to  restrict
              the output to a subset of the set of readonly names.  The --pp op-
              tion displays output in a format that may be reused as input.

              rreeaaddoonnllyy  allows  the  value of a variable to be set at the same
              time the readonly attribute is changed by following the variable
              name with =_v_a_l_u_e.  This sets the value of  the  variable  is  to
              _v_a_l_u_e while modifying the readonly attribute.

              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]
              Stop  executing  a shell function or sourced file and return the
              value specified by _n to its caller.  If _n is omitted, the return
              status is that of the last command executed.  If rreettuurrnn is  exe-
              cuted  by a trap handler, the last command used to determine the
              status is the last command executed before the trap handler.  If
              rreettuurrnn is executed during a DDEEBBUUGG trap, the last command used to
              determine the status is the last command executed  by  the  trap
              handler before rreettuurrnn was invoked.

              When rreettuurrnn is used to terminate execution of a script being ex-
              ecuted  by  the ..  (ssoouurrccee) command, it causes the shell to stop
              executing that script and return either _n or the exit status  of
              the  last  command executed within the script as the exit status
              of the script.  If _n is supplied, the return value is its  least
              significant 8 bits.

              Any  command  associated with the RREETTUURRNN trap is executed before
              execution resumes after the function or script.

              The return status is non-zero if rreettuurrnn is  supplied  a  non-nu-
              meric argument, or is used outside a function and not during ex-
              ecution of a script by .. or ssoouurrccee.

       sseett [--aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [--oo _o_p_t_i_o_n_-_n_a_m_e] [----] [--] [_a_r_g ...]
       sseett [++aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [++oo _o_p_t_i_o_n_-_n_a_m_e] [----] [--] [_a_r_g ...]
       sseett --oo
       sseett ++oo Without  options, display the name and value of each shell vari-
              able in a format that can be reused as input for setting or  re-
              setting the currently-set variables.  Read-only variables cannot
              be  reset.  In posix mode, only shell variables are listed.  The
              output is sorted according to the current locale.  When  options
              are  specified,  they  set or unset shell attributes.  Any argu-
              ments remaining after option processing are  treated  as  values
              for the positional parameters and are assigned, in order, to $$11,
              $$22,  ...,  $$_n.   Options, if specified, have the following mean-
              ings:
              --aa      Each variable or function that is created or modified is
                      given the export attribute and marked for export to  the
                      environment of subsequent commands.
              --bb      Report  the status of terminated background jobs immedi-
                      ately, rather than before the next primary prompt or af-
                      ter a foreground command terminates.  This is  effective
                      only when job control is enabled.
              --ee      Exit  immediately  if a _p_i_p_e_l_i_n_e (which may consist of a
                      single _s_i_m_p_l_e _c_o_m_m_a_n_d), a _l_i_s_t, or  a  _c_o_m_p_o_u_n_d  _c_o_m_m_a_n_d
                      (see  SSHHEELLLL  GGRRAAMMMMAARR  in _b_a_s_h(1)), 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 reserved word, part of the test follow-
                      ing the iiff or eelliiff reserved words, part of  any  command
                      executed in a &&&& or |||| list except the command following
                      the  final  &&&&  or ||||, any command in a pipeline but the
                      last (subject to the state of  the  ppiippeeffaaiill  shell  op-
                      tion),  or  if  the  command's return value is being in-
                      verted with !!.  If a compound command other than a  sub-
                      shell returns a non-zero status because a command failed
                      while  --ee was being ignored, the shell does not exit.  A
                      trap on EERRRR, if set, is executed before the shell exits.
                      This option applies to the shell  environment  and  each
                      subshell  environment  separately (see CCOOMMMMAANNDD EEXXEECCUUTTIIOONN
                      EENNVVIIRROONNMMEENNTT in _b_a_s_h(1)), and may cause subshells to exit
                      before executing all the commands in the subshell.

                      If a compound command or shell function  executes  in  a
                      context  where --ee is being ignored, none of the commands
                      executed within the compound command  or  function  body
                      will  be  affected  by the --ee setting, even if --ee is set
                      and a command returns a failure status.  If  a  compound
                      command  or  shell function sets --ee while executing in a
                      context where --ee is ignored, that setting will not  have
                      any  effect  until  the  compound command or the command
                      containing the function call completes.
              --ff      Disable pathname expansion.
              --hh      Remember the location of commands as they are looked  up
                      for execution.  This is enabled by default.
              --kk      All  arguments  in the form of assignment statements are
                      placed in the environment for a command, not just  those
                      that precede the command name.
              --mm      Monitor  mode.   Job control is enabled.  This option is
                      on by default for interactive  shells  on  systems  that
                      support  it (see JJOOBB CCOONNTTRROOLL in _b_a_s_h(1)).  All processes
                      run in a separate process group.  When a background  job
                      completes,  the  shell prints a line containing its exit
                      status.
              --nn      Read commands but do not execute them.  This may be used
                      to check a shell script for syntax errors.  This is  ig-
                      nored by interactive shells.
              --oo _o_p_t_i_o_n_-_n_a_m_e
                      The _o_p_t_i_o_n_-_n_a_m_e can be one of the following:
                      aalllleexxppoorrtt
                              Same as --aa.
                      bbrraacceeeexxppaanndd
                              Same as --BB.
                      eemmaaccss   Use  an  emacs-style command line editing inter-
                              face.  This is enabled by default when the shell
                              is interactive, unless the shell is started with
                              the ----nnooeeddiittiinngg option.  This also  affects  the
                              editing interface used for rreeaadd --ee.
                      eerrrreexxiitt Same as --ee.
                      eerrrrttrraaccee
                              Same as --EE.
                      ffuunnccttrraaccee
                              Same as --TT.
                      hhaasshhaallll Same as --hh.
                      hhiisstteexxppaanndd
                              Same as --HH.
                      hhiissttoorryy Enable  command history, as described in _b_a_s_h(1)
                              under HHIISSTTOORRYY.  This option is on by default  in
                              interactive shells.
                      iiggnnoorreeeeooff
                              The  effect  is as if the shell command had been
                              executed (see SShheellll VVaarriiaabblleess in _b_a_s_h(1)).
                      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   Enable posix mode; change the behavior  of  bbaasshh
                              where  the  default  operation  differs from the
                              POSIX standard to match the standard.   See  SSEEEE
                              AALLSSOO  in  _b_a_s_h(1)  for a reference to a document
                              that details how posix mode affects  bash's  be-
                              havior.
                      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,  sseett  prints  the
                      current  shell  option settings.  If ++oo is supplied with
                      no _o_p_t_i_o_n_-_n_a_m_e, sseett prints a series of sseett  commands  to
                      recreate  the  current  option  settings on the standard
                      output.
              --pp      Turn on _p_r_i_v_i_l_e_g_e_d mode.  In this mode, the  shell  does
                      not  read  the $$EENNVV and $$BBAASSHH__EENNVV files, shell functions
                      are not inherited from the environment,  and  the  SSHHEELL--
                      LLOOPPTTSS,  BBAASSHHOOPPTTSS,  CCDDPPAATTHH,  and GGLLOOBBIIGGNNOORREE variables, if
                      they appear in the environment,  are  ignored.   If  the
                      shell  is started with the effective user (group) id not
                      equal to the real user (group) id, and the --pp option  is
                      not  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.
              --rr      Enable restricted shell mode.  This option cannot be un-
                      set once it has been set.
              --tt      Exit after reading and executing one command.
              --uu      Treat unset variables and parameters other than the spe-
                      cial  parameters and or array variables subscripted with
                      or as an error when performing parameter expansion.   If
                      expansion  is  attempted on an unset variable or parame-
                      ter, the shell prints an error message, and, if not  in-
                      teractive, 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, to
                      the standard error.
              --BB      The shell performs brace expansion (see BBrraaccee  EExxppaannssiioonn
                      in _b_a_s_h(1)).  This is on by default.
              --CC      If  set,  bbaasshh  does not overwrite an existing file with
                      the >>, >>&&, and  <<>>  redirection  operators.   Using  the
                      redirection  operator >>|| instead of >> will override this
                      and force the creation of an output file.
              --EE      If set, any trap on EERRRR is inherited by shell functions,
                      command substitutions, and commands executed in  a  sub-
                      shell  environment.  The EERRRR trap is normally not inher-
                      ited in such cases.
              --HH      Enable !!  style history substitution.  This option is on
                      by default when the shell is interactive.
              --PP      If set, the shell does not resolve symbolic  links  when
                      executing  commands  such  as ccdd that change the current
                      working  directory.   It  uses  the  physical  directory
                      structure instead.  By default, bbaasshh follows the logical
                      chain  of  directories  when  performing  commands which
                      change the current directory.
              --TT      If set, any traps on DDEEBBUUGG and RREETTUURRNN are  inherited  by
                      shell functions, command substitutions, and commands ex-
                      ecuted  in a subshell environment.  The DDEEBBUUGG and RREETTUURRNN
                      traps are normally not inherited in such cases.
              ----      If no arguments follow this option, unset the positional
                      parameters.  Otherwise, set the positional parameters to
                      the _a_r_gs, even if some of them begin with a --.
              --       Signal the end of options, and assign all remaining _a_r_gs
                      to the positional parameters.  The --xx and --vv options are
                      turned off.  If there are no _a_r_gs, the positional  para-
                      meters remain unchanged.

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

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

       sshhoopptt [--ppqqssuu] [--oo] [_o_p_t_n_a_m_e ...]
              Toggle the values of settings controlling optional shell  behav-
              ior.   The settings can be either those listed below, or, if the
              --oo option is used, those available with the --oo option to the sseett
              builtin command.

              With no options, or with the --pp option, display a  list  of  all
              settable  options,  with an indication of whether or not each is
              set; if any _o_p_t_n_a_m_e_s are supplied, the output is  restricted  to
              those options.  The --pp option displays output in a form that may
              be reused as input.

              Other options have the following meanings:
              --ss     Enable (set) each _o_p_t_n_a_m_e.
              --uu     Disable (unset) each _o_p_t_n_a_m_e.
              --qq     Suppresses  normal output (quiet mode); the return status
                     indicates whether the _o_p_t_n_a_m_e is set or unset.  If multi-
                     ple _o_p_t_n_a_m_e arguments are supplied with  --qq,  the  return
                     status is zero if all _o_p_t_n_a_m_e_s are enabled; non-zero oth-
                     erwise.
              --oo     Restricts  the  values of _o_p_t_n_a_m_e to be those defined for
                     the --oo option to the sseett builtin.

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

              The  return  status when listing options is zero if all _o_p_t_n_a_m_e_s
              are enabled, non-zero otherwise.  When setting or unsetting  op-
              tions,  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:

              aarrrraayy__eexxppaanndd__oonnccee
                      If set, the shell suppresses multiple evaluation of  as-
                      sociative and indexed array subscripts during arithmetic
                      expression evaluation, while executing builtins that can
                      perform   variable   assignments,  and  while  executing
                      builtins that perform array dereferencing.
              aassssoocc__eexxppaanndd__oonnccee
                      Deprecated; a synonym for aarrrraayy__eexxppaanndd__oonnccee.
              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.
              bbaasshh__ssoouurrccee__ffuullllppaatthh
                      If set, filenames added to the BBAASSHH__SSOOUURRCCEE  array  vari-
                      able  are  converted  to full pathnames (see SShheellll VVaarrii--
                      aabblleess above).
              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, the ccdd command attempts to correct minor  errors
                      in  the spelling of a directory component.  Minor errors
                      include transposed characters, a missing character,  and
                      one extra character.  If ccdd corrects the directory name,
                      it  prints  the corrected filename, and the command pro-
                      ceeds.  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, bbaasshh performs a normal path
                      search.
              cchheecckkjjoobbss
                      If set, bbaasshh lists the status of any stopped and running
                      jobs before exiting an interactive shell.  If  any  jobs
                      are running, bbaasshh defers the exit until a second exit is
                      attempted  without  an intervening command (see JJOOBB CCOONN--
                      TTRROOLL in _b_a_s_h(1)).  The shell always postpones exiting if
                      any jobs are stopped.
              cchheecckkwwiinnssiizzee
                      If set, bbaasshh checks the window size after each  external
                      (non-builtin)  command  and,  if  necessary, updates the
                      values of LLIINNEESS and CCOOLLUUMMNNSS, using the  file  descriptor
                      associated  with the standard error if it is a terminal.
                      This option is enabled by default.
              ccmmddhhiisstt If set, bbaasshh attempts to save all lines of  a  multiple-
                      line  command  in  the  same history entry.  This allows
                      easy re-editing of multi-line commands.  This option  is
                      enabled  by  default,  but only has an effect if command
                      history is enabled, as described in _b_a_s_h(1)  under  HHIISS--
                      TTOORRYY.
              ccoommppaatt3311
              ccoommppaatt3322
              ccoommppaatt4400
              ccoommppaatt4411
              ccoommppaatt4422
              ccoommppaatt4433
              ccoommppaatt4444
                      These  control aspects of the shell's compatibility mode
                      (see SSHHEELLLL CCOOMMPPAATTIIBBIILLIITTYY MMOODDEE in _b_a_s_h(1)).
              ccoommpplleettee__ffuullllqquuoottee
                      If set, bbaasshh quotes all shell  metacharacters  in  file-
                      names  and  directory  names when performing completion.
                      If not set, bbaasshh removes metacharacters such as the dol-
                      lar sign from the set of characters that will be  quoted
                      in  completed filenames when these metacharacters appear
                      in shell variable references in words to  be  completed.
                      This  means that dollar signs in variable names that ex-
                      pand to directories will not  be  quoted;  however,  any
                      dollar  signs appearing in filenames will not be quoted,
                      either.  This is active only when bash  is  using  back-
                      slashes  to quote completed filenames.  This variable is
                      set by default, which is the default  bash  behavior  in
                      versions through 4.2.
              ddiirreexxppaanndd
                      If  set,  bbaasshh replaces directory names with the results
                      of word expansion when performing  filename  completion.
                      This  changes  the  contents  of  the  rreeaaddlliinnee  editing
                      buffer.  If not set, bbaasshh attempts to preserve what  the
                      user typed.
              ddiirrssppeellll
                      If  set,  bbaasshh attempts spelling correction on directory
                      names during word completion if the directory name  ini-
                      tially supplied does not exist.
              ddoottgglloobb If  set, bbaasshh includes filenames beginning with a in the
                      results of pathname expansion.  The filenames _.  and  _._.
                      must  always  be  matched explicitly, even if ddoottgglloobb is
                      set.
              eexxeeccffaaiill
                      If set, a non-interactive shell will not exit if it can-
                      not execute the file specified as  an  argument  to  the
                      eexxeecc  builtin.   An  interactive  shell does not exit if
                      eexxeecc fails.
              eexxppaanndd__aalliiaasseess
                      If set, aliases are expanded as described in _b_a_s_h(1) un-
                      der AALLIIAASSEESS.  This option is enabled by default for  in-
                      teractive shells.
              eexxttddeebbuugg
                      If  set at shell invocation, or in a shell startup file,
                      arrange to execute the debugger profile before the shell
                      starts, identical to the ----ddeebbuuggggeerr option.  If set  af-
                      ter  invocation,  behavior intended for use by debuggers
                      is enabled:
                      11..     The --FF option to the ddeeccllaarree builtin displays the
                             source file name and line number corresponding to
                             each function name supplied as an argument.
                      22..     If the command run by the DDEEBBUUGG  trap  returns  a
                             non-zero  value,  the next command is skipped and
                             not executed.
                      33..     If the command run by the DDEEBBUUGG  trap  returns  a
                             value  of 2, and the shell is executing in a sub-
                             routine (a shell function or a shell script  exe-
                             cuted  by  the  ..  or ssoouurrccee builtins), the shell
                             simulates a call to rreettuurrnn.
                      44..     BBAASSHH__AARRGGCC and BBAASSHH__AARRGGVV are updated as  described
                             in their descriptions in _b_a_s_h(1)).
                      55..     Function  tracing  is  enabled: command substitu-
                             tion, shell functions, and subshells invoked with
                             (( _c_o_m_m_a_n_d )) inherit the DDEEBBUUGG and RREETTUURRNN traps.
                      66..     Error tracing is enabled:  command  substitution,
                             shell  functions,  and  subshells  invoked with ((
                             _c_o_m_m_a_n_d )) inherit the EERRRR trap.
              eexxttgglloobb If set, enable the extended  pattern  matching  features
                      described in _b_a_s_h(1) under PPaatthhnnaammee EExxppaannssiioonn.
              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 in _b_a_s_h(1) for a
                      description of FFIIGGNNOORREE.  This option is enabled  by  de-
                      fault.
              gglloobbaasscciiiirraannggeess
                      If  set,  range  expressions  used  in  pattern matching
                      bracket expressions (see PPaatttteerrnn  MMaattcchhiinngg  in  _b_a_s_h(1))
                      behave as if in the traditional C locale when performing
                      comparisons.   That  is,  pattern matching does not take
                      the current locale's collating sequence into account, so
                      bb will not collate between AA and BB, and  upper-case  and
                      lower-case ASCII characters will collate together.
              gglloobbsskkiippddoottss
                      If  set,  pathname  expansion will never match the file-
                      names _. and _._. even if the pattern begins  with  a  This
                      option is enabled by default.
              gglloobbssttaarr
                      If set, the pattern **** used in a pathname expansion con-
                      text  will  match all files and zero or more directories
                      and subdirectories.  If the pattern is followed by a  //,
                      only directories and subdirectories match.
              ggnnuu__eerrrrffmmtt
                      If set, shell error messages are written in the standard
                      GNU error message format.
              hhiissttaappppeenndd
                      If  set,  the history list is appended to the file named
                      by the value of the HHIISSTTFFIILLEE variable when the shell ex-
                      its, rather than overwriting the file.
              hhiissttrreeeeddiitt
                      If set, and rreeaaddlliinnee is being used, the  user  is  given
                      the  opportunity  to  re-edit a failed history substitu-
                      tion.
              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  in
                      _b_a_s_h(1)).  This is enabled by default.
              hhuuppoonneexxiitt
                      If set, bbaasshh will send SSIIGGHHUUPP to all jobs when an inter-
                      active login shell exits.
              iinnhheerriitt__eerrrreexxiitt
                      If  set,  command substitution inherits the value of the
                      eerrrreexxiitt option, instead of unsetting it in the  subshell
                      environment.   This option is enabled when posix mode is
                      enabled.
              iinntteerraaccttiivvee__ccoommmmeennttss
                      In an interactive shell, a word beginning with ##  causes
                      that  word  and all remaining characters on that line to
                      be ignored, as in a non-interactive shell (see  CCOOMMMMEENNTTSS
                      in _b_a_s_h(1)).  This option is enabled by default.
              llaassttppiippee
                      If  set,  and  job control is not active, the shell runs
                      the last command of a pipeline not executed in the back-
                      ground in the current shell environment.
              lliitthhiisstt If set, and the ccmmddhhiisstt option  is  enabled,  multi-line
                      commands are saved to the history with embedded newlines
                      rather than using semicolon separators where possible.
              llooccaallvvaarr__iinnhheerriitt
                      If set, local variables inherit the value and attributes
                      of a variable of the same name that exists at a previous
                      scope before any new value is assigned.  The nameref at-
                      tribute is not inherited.
              llooccaallvvaarr__uunnsseett
                      If  set,  calling  uunnsseett  on local variables in previous
                      function scopes marks them so  subsequent  lookups  find
                      them unset until that function returns.  This is identi-
                      cal  to the behavior of unsetting local variables at the
                      current function scope.
              llooggiinn__sshheellll
                      The shell sets this option if it is started as  a  login
                      shell (see IINNVVOOCCAATTIIOONN in _b_a_s_h(1)).  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,  bbaasshh
                      displays the message
              nnoo__eemmppttyy__ccmmdd__ccoommpplleettiioonn
                      If set, and rreeaaddlliinnee is being used, bbaasshh does not search
                      PPAATTHH  for  possible  completions  when completion is at-
                      tempted on an empty line.
              nnooccaasseegglloobb
                      If set, bbaasshh matches  filenames  in  a  case-insensitive
                      fashion when performing pathname expansion (see PPaatthhnnaammee
                      EExxppaannssiioonn in _b_a_s_h(1)).
              nnooccaasseemmaattcchh
                      If  set,  bbaasshh  matches  patterns  in a case-insensitive
                      fashion when performing matching while executing ccaassee or
                      [[[[ conditional commands, when performing pattern substi-
                      tution word expansions, or when filtering possible  com-
                      pletions as part of programmable completion.
              nnooeexxppaanndd__ttrraannssllaattiioonn
                      If  set,  bbaasshh  encloses  the translated results of $$...
                      quoting in single quotes instead of double  quotes.   If
                      the string is not translated, this has no effect.
              nnuullllgglloobb
                      If set, pathname expansion patterns which match no files
                      (see  PPaatthhnnaammee  EExxppaannssiioonn  in _b_a_s_h(1)) expand to nothing
                      and are removed, rather than expanding to themselves.
              ppaattssuubb__rreeppllaacceemmeenntt
                      If set, bbaasshh expands occurrences of && in the replacement
                      string of pattern substitution to the  text  matched  by
                      the  pattern,  as described under PPaarraammeetteerr EExxppaannssiioonn in
                      _b_a_s_h(1).  This option is enabled by default.
              pprrooggccoommpp
                      If set, enable the  programmable  completion  facilities
                      (see  PPrrooggrraammmmaabbllee  CCoommpplleettiioonn in _b_a_s_h(1)).  This option
                      is enabled by default.
              pprrooggccoommpp__aalliiaass
                      If set, and programmable  completion  is  enabled,  bbaasshh
                      treats  a command name that doesn't have any completions
                      as a possible alias and attempts alias expansion.  If it
                      has an alias, bbaasshh attempts programmable completion  us-
                      ing the command word resulting from the expanded alias.
              pprroommppttvvaarrss
                      If set, prompt strings undergo parameter expansion, com-
                      mand  substitution,  arithmetic expansion, and quote re-
                      moval after being expanded as described in PPRROOMMPPTTIINNGG  in
                      _b_a_s_h(1).  This option is enabled by default.
              rreessttrriicctteedd__sshheellll
                      The  shell  sets  this  option  if  it is started in re-
                      stricted mode (see RREESSTTRRIICCTTEEDD SSHHEELLLL  in  _b_a_s_h(1)).   The
                      value  may  not  be changed.  This is not reset when the
                      startup files are executed, allowing the  startup  files
                      to discover 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  when  the --pp option is not supplied.  This op-
                      tion is enabled by default.
              vvaarrrreeddiirr__cclloossee
                      If set, the shell automatically closes file  descriptors
                      assigned  using  the  _{_v_a_r_n_a_m_e_}  redirection syntax (see
                      RREEDDIIRREECCTTIIOONN in _b_a_s_h(1)) instead  of  leaving  them  open
                      when the command completes.
              xxppgg__eecchhoo
                      If  set,  the  eecchhoo builtin expands backslash-escape se-
                      quences by default.  If the ppoossiixx shell option  is  also
                      enabled, eecchhoo does not interpret any options.

       ssuussppeenndd [--ff]
              Suspend  the execution of this shell until it receives a SSIIGGCCOONNTT
              signal.  A login shell, or a shell without job control  enabled,
              cannot  be suspended; the --ff option will override this and force
              the suspension.  The return status is 0 unless the  shell  is  a
              login  shell  or  job  control is not enabled and --ff is not sup-
              plied.

       tteesstt _e_x_p_r
       [[ _e_x_p_r ]]
              Return a status of 0 (true) or 1 (false) depending on the evalu-
              ation of the conditional expression  _e_x_p_r.   Each  operator  and
              operand  must  be a separate argument.  Expressions are composed
              of the primaries described in _b_a_s_h(1) under CCOONNDDIITTIIOONNAALL  EEXXPPRREESS--
              SSIIOONNSS.  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  de-
              pends on the number of arguments; see below.  tteesstt uses operator
              precedence when there are five or more arguments.
              !! _e_x_p_r True if _e_x_p_r is false.
              (( _e_x_p_r ))
                     Returns  the value of _e_x_p_r.  This may be used to override
                     normal operator precedence.
              _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 in
                     _b_a_s_h(1) under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the expression  is
                     true if the unary test is true.  If the first argument is
                     not a valid unary conditional operator, the expression is
                     false.
              3 arguments
                     The following conditions are applied in the order listed.
                     If  the  second argument is one of the binary conditional
                     operators listed in  _b_a_s_h(1)  under  CCOONNDDIITTIIOONNAALL  EEXXPPRREESS--
                     SSIIOONNSS,  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-argu-
                     ment  test  using the second and third arguments.  If the
                     first argument is exactly (( and the third argument is ex-
                     actly )), the result is the one-argument test of the  sec-
                     ond argument.  Otherwise, the expression is false.
              4 arguments
                     The following conditions are applied in the order listed.
                     If the first argument is !!, the result is the negation of
                     the  three-argument  expression composed of the remaining
                     arguments.  If the first argument is exactly  ((  and  the
                     fourth argument is exactly )), the result is the two-argu-
                     ment  test of the second and third arguments.  Otherwise,
                     the expression  is  parsed  and  evaluated  according  to
                     precedence using the rules listed above.
              5 or more arguments
                     The  expression  is  parsed  and  evaluated  according to
                     precedence using the rules listed above.

              When the shell is in posix mode, or if the expression is part of
              the [[[[ command, the << and >> operators sort using the current lo-
              cale.  If the shell is not in posix mode, the tteesstt  and  [[  com-
              mands sort lexicographically using ASCII ordering.

              The  historical operator-precedence parsing with 4 or more argu-
              ments can lead to ambiguities when it  encounters  strings  that
              look  like  primaries.  The POSIX standard has deprecated the --aa
              and --oo primaries and enclosing expressions  within  parentheses.
              Scripts  should  no longer use them.  It's much more reliable to
              restrict test invocations to a single primary,  and  to  replace
              uses of --aa and --oo with the shell's &&&& and |||| list operators.

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

       ttrraapp [--llppPP] [[_a_c_t_i_o_n] _s_i_g_s_p_e_c ...]
              The _a_c_t_i_o_n is a command that is read and executed when the shell
              receives any of the signals _s_i_g_s_p_e_c.  If _a_c_t_i_o_n is  absent  (and
              there is a single _s_i_g_s_p_e_c) or --, each specified _s_i_g_s_p_e_c is reset
              to  the  value  it had when the shell was started.  If _a_c_t_i_o_n 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  no arguments are supplied, ttrraapp displays the actions associ-
              ated with each trapped signal as a set of ttrraapp commands that can
              be reused as shell input to restore the current signal  disposi-
              tions.   If  --pp  is  given, and _a_c_t_i_o_n is not present, then ttrraapp
              displays the actions associated with each _s_i_g_s_p_e_c  or,  if  none
              are supplied, for all trapped signals, as a set of ttrraapp commands
              that  can be reused as shell input to restore the current signal
              dispositions.  The --PP option  behaves  similarly,  but  displays
              only  the actions associated with each _s_i_g_s_p_e_c argument.  --PP re-
              quires at least one _s_i_g_s_p_e_c argument.  The --PP or --pp options  may
              be  used  in a subshell environment (e.g., command substitution)
              and, as long as they are used before ttrraapp is used  to  change  a
              signal's handling, will display the state of its parent's traps.

              The  --ll  option  prints  a list of signal names and their corre-
              sponding 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 insen-
              sitive  and  the SSIIGG prefix is optional.  If --ll is supplied with
              no _s_i_g_s_p_e_c arguments, it prints a list of valid signal names.

              If a _s_i_g_s_p_e_c is EEXXIITT (0), _a_c_t_i_o_n is executed on  exit  from  the
              shell.   If  a _s_i_g_s_p_e_c is DDEEBBUUGG, _a_c_t_i_o_n 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,  ((
              arithmetic  command, [[ conditional command, arithmetic _f_o_r com-
              mand, and before the first command executes in a shell  function
              (see SSHHEELLLL GGRRAAMMMMAARR in _b_a_s_h(1)).  Refer to the description of the
              eexxttddeebbuugg  shell option (see sshhoopptt in _b_a_s_h(1)) for details of its
              effect on the DDEEBBUUGG trap.  If a _s_i_g_s_p_e_c is RREETTUURRNN, _a_c_t_i_o_n is ex-
              ecuted each time a shell function or a script executed with  the
              .. or ssoouurrccee builtins finishes executing.

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

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

       ttrruuee   Does nothing, returns a 0 status.

       ttyyppee [--aaffttppPP] _n_a_m_e [_n_a_m_e ...]
              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 executable file, re-
              spectively.  If the _n_a_m_e is not found, ttyyppee prints  nothing  and
              returns a non-zero exit status.

              If  the  --pp  option is used, ttyyppee either returns the pathname of
              the executable file that would be found by searching  $$PPAATTHH  for
              _n_a_m_e  or nothing if would not return _f_i_l_e.  The --PP option forces
              a PPAATTHH search for each _n_a_m_e, even if would not return _f_i_l_e.   If
              _n_a_m_e is present in the table of hashed commands, --pp and --PP print
              the hashed value, which is not necessarily the file that appears
              first in PPAATTHH.

              If  the  --aa  option  is used, ttyyppee prints all of the places that
              contain a command named _n_a_m_e.  This includes  aliases,  reserved
              words,  functions, and builtins, but the path search options (--pp
              and --PP) can be supplied to restrict  the  output  to  executable
              files.   ttyyppee does not consult the table of hashed commands when
              using --aa with --pp, and only performs a PPAATTHH search for _n_a_m_e.

              The --ff option suppresses shell function lookup, as with the ccoomm--
              mmaanndd builtin.  ttyyppee returns true if all  of  the  arguments  are
              found, false if any are not found.

       uulliimmiitt [--HHSS] --aa
       uulliimmiitt [--HHSS] [--bbccddeeffiikkllmmnnppqqrrssttuuvvxxPPRRTT [_l_i_m_i_t]]
              Provides  control  over the resources available to the shell and
              to processes it starts, on systems that allow such control.

              The --HH and --SS options specify whether 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, uulliimmiitt sets both the soft and hard limits.

              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, uulliimmiitt  prints
              the  current value of the soft limit of the resource, unless the
              --HH option is given.  When more than one resource  is  specified,
              the  limit name and unit, if appropriate, are printed before the
              value.  Other options are interpreted as follows:
              --aa     Report all current limits; no limits are set.
              --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 (
              --ff     The maximum size of files written by the  shell  and  its
                     children.
              --ii     The maximum number of pending signals.
              --kk     The maximum number of kqueues that may be allocated.
              --ll     The maximum size that may be locked into memory.
              --mm     The  maximum resident set size (many systems do not honor
                     this limit).
              --nn     The maximum number of open file descriptors (most systems
                     do not allow this value to be set).
              --pp     The pipe size in 512-byte blocks (this may not be set).
              --qq     The maximum number of bytes in POSIX message queues.
              --rr     The maximum real-time scheduling priority.
              --ss     The maximum stack size.
              --tt     The maximum amount of cpu time in seconds.
              --uu     The maximum number of processes  available  to  a  single
                     user.
              --vv     The  maximum  amount  of  virtual memory available to the
                     shell and, on some systems, to its children.
              --xx     The maximum number of file locks.
              --PP     The maximum number of pseudoterminals.
              --RR     The maximum time  a  real-time  process  can  run  before
                     blocking, in microseconds.
              --TT     The maximum number of threads.

              If  _l_i_m_i_t  is  supplied, and the --aa option is not used, _l_i_m_i_t is
              the new value of the specified resource.  If no option  is  sup-
              plied, then --ff is assumed.

              Values  are  in 1024-byte increments, except for --tt, which is in
              seconds; --RR, which is in microseconds; --pp, which is in units  of
              512-byte  blocks; --PP, --TT, --bb, --kk, --nn, and --uu, which are unscaled
              values; and, when in  posix  mode,  --cc  and  --ff,  which  are  in
              512-byte  increments.   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]
              Set the user file-creation mask to _m_o_d_e.  If _m_o_d_e begins with  a
              digit, it is interpreted as an octal number; otherwise it is in-
              terpreted  as  a  symbolic mode mask similar to that accepted by
              _c_h_m_o_d(1).  If _m_o_d_e is omitted, uummaasskk prints the current value of
              the mask.  The --SS option without a _m_o_d_e argument prints the mask
              in a symbolic format; 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  zero
              if  the mode was successfully changed or if no _m_o_d_e argument was
              supplied, and non-zero otherwise.

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

       uunnsseett [-ffvv] [-nn] [_n_a_m_e ...]
              For each _n_a_m_e, remove the corresponding  variable  or  function.
              If the --vv option is given, each _n_a_m_e refers to a shell variable,
              and  that  variable  is  removed.  If --ff is specified, each _n_a_m_e
              refers to a shell function, and the function definition  is  re-
              moved.   If  the  --nn  option is supplied, and _n_a_m_e is a variable
              with the _n_a_m_e_r_e_f attribute, _n_a_m_e will be unset rather  than  the
              variable  it  references.   --nn has no effect if the --ff option is
              supplied.  Read-only variables and functions may not  be  unset.
              When  variables  or functions are removed, they are also removed
              from the environment passed to subsequent commands.  If  no  op-
              tions  are supplied, each _n_a_m_e refers to a variable; if there is
              no variable by that name, a function with that name, if any,  is
              unset.   Some  shell  variables  may  not  be  unset.  If any of
              BBAASSHH__AALLIIAASSEESS,  BBAASSHH__AARRGGVV00,  BBAASSHH__CCMMDDSS,  BBAASSHH__CCOOMMMMAANNDD,  BBAASSHH__SSUUBB--
              SSHHEELLLL,   BBAASSHHPPIIDD,   CCOOMMPP__WWOORRDDBBRREEAAKKSS,   DDIIRRSSTTAACCKK,  EEPPOOCCHHRREEAALLTTIIMMEE,
              EEPPOOCCHHSSEECCOONNDDSS, FFUUNNCCNNAAMMEE, GGRROOUUPPSS, HHIISSTTCCMMDD,  LLIINNEENNOO,  RRAANNDDOOMM,  SSEECC--
              OONNDDSS,  or SSRRAANNDDOOMM are unset, they lose their special properties,
              even if they are subsequently reset.  The exit  status  is  true
              unless a _n_a_m_e is readonly or may not be unset.

       wwaaiitt [--ffnn] [--pp _v_a_r_n_a_m_e] [_i_d ...]
              Wait for each specified child process _i_d and return the termina-
              tion  status of the last _i_d.  Each _i_d may be a process ID _p_i_d or
              a job specification _j_o_b_s_p_e_c; if  a  jobspec  is  supplied,  wwaaiitt
              waits for all processes in the job.

              If  no  options  or _i_ds are supplied, wwaaiitt waits for all running
              background jobs and the last-executed process  substitution,  if
              its process id is the same as $$!!, and the return status is zero.

              If  the  --nn  option  is  supplied, wwaaiitt waits for any one of the
              given _i_ds or, if no _i_ds are supplied, any job or process substi-
              tution, to complete and returns its exit status.  If none of the
              supplied _i_ds is a child of the shell, or if no _i_ds are  supplied
              and  the  shell has no unwaited-for children, the exit status is
              127.

              If the --pp option is supplied, wwaaiitt assigns the  process  or  job
              identifier  of  the job for which the exit status is returned to
              the variable _v_a_r_n_a_m_e named by the option  argument.   The  vari-
              able,  which cannot be readonly, will be unset initially, before
              any assignment.  This is useful only when used with the  --nn  op-
              tion.

              Supplying  the  --ff  option,  when job control is enabled, forces
              wwaaiitt to wait for each _i_d to terminate before returning its  sta-
              tus, instead of returning when it changes status.

              If  none  of  the  _i_ds  specify  one of the shell's active child
              processes, the return status is 127.  If wwaaiitt is interrupted  by
              a  signal,  any _v_a_r_n_a_m_e will remain unset, and the return status
              will be greater than 128, as described under SSIIGGNNAALLSS in _b_a_s_h(1).
              Otherwise, the return status is the exit status of the last _i_d.

SSHHEELLLL CCOOMMPPAATTIIBBIILLIITTYY MMOODDEE
       Bash-4.0 introduced the concept of a _s_h_e_l_l _c_o_m_p_a_t_i_b_i_l_i_t_y _l_e_v_e_l,  speci-
       fied as a set of options to the shopt builtin (ccoommppaatt3311, ccoommppaatt3322, ccoomm--
       ppaatt4400,  ccoommppaatt4411,  and so on).  There is only one current compatibility
       level -- each option is mutually exclusive.  The compatibility level is
       intended to allow users to select behavior from previous versions  that
       is  incompatible  with newer versions while they migrate scripts to use
       current features and behavior.  It's intended to be a  temporary  solu-
       tion.

       This  section does not mention behavior that is standard for a particu-
       lar version (e.g., setting ccoommppaatt3322 means that quoting the  right  hand
       side  of  the regexp matching operator quotes special regexp characters
       in the word, which is default behavior in bash-3.2 and subsequent  ver-
       sions).

       If  a  user enables, say, ccoommppaatt3322, it may affect the behavior of other
       compatibility levels up to  and  including  the  current  compatibility
       level.   The  idea  is  that each compatibility level controls behavior
       that changed in that version of bbaasshh, but that behavior may  have  been
       present  in  earlier versions.  For instance, the change to use locale-
       based comparisons with the [[[[ command came  in  bash-4.1,  and  earlier
       versions used ASCII-based comparisons, so enabling ccoommppaatt3322 will enable
       ASCII-based  comparisons  as  well.  That granularity may not be suffi-
       cient for all uses, and as a result users should  employ  compatibility
       levels  carefully.   Read the documentation for a particular feature to
       find out the current behavior.

       Bash-4.3 introduced a new shell variable: BBAASSHH__CCOOMMPPAATT.  The  value  as-
       signed to this variable (a decimal version number like 4.2, or an inte-
       ger  corresponding to the ccoommppaatt_N_N option, like 42) determines the com-
       patibility level.

       Starting with bash-4.4, bbaasshh began deprecating older compatibility lev-
       els.  Eventually, the options will be removed in favor of BBAASSHH__CCOOMMPPAATT.

       Bash-5.0 was the final version for which there was an individual  shopt
       option  for the previous version.  BBAASSHH__CCOOMMPPAATT is the only mechanism to
       control the compatibility level in versions newer than bash-5.0.

       The following table describes the behavior changes controlled  by  each
       compatibility level setting.  The ccoommppaatt_N_N tag is used as shorthand for
       setting the compatibility level to _N_N using one of the following mecha-
       nisms.   For versions prior to bash-5.0, the compatibility level may be
       set using the corresponding ccoommppaatt_N_N shopt option.   For  bash-4.3  and
       later  versions,  the  BBAASSHH__CCOOMMPPAATT variable is preferred, and it is re-
       quired for bash-5.1 and later versions.

       ccoommppaatt3311
              +o      Quoting the rhs of the [[[[ command's regexp matching oper-
                     ator (=) has no special effect.

       ccoommppaatt3322
              +o      The << and >> operators to the [[[[ command do  not  consider
                     the current locale when comparing strings; they use ASCII
                     ordering.

       ccoommppaatt4400
              +o      The  <<  and >> operators to the [[[[ command do not consider
                     the current locale when comparing strings; they use ASCII
                     ordering.  BBaasshh versions prior to bash-4.1 use ASCII col-
                     lation and _s_t_r_c_m_p(3); bash-4.1 and later use the  current
                     locale's collation sequence and _s_t_r_c_o_l_l(3).

       ccoommppaatt4411
              +o      In  posix mode, ttiimmee may be followed by options and still
                     be recognized as a reserved word (this is POSIX interpre-
                     tation 267).
              +o      In _p_o_s_i_x mode, the parser requires that an even number of
                     single quotes occur in the  _w_o_r_d  portion  of  a  double-
                     quoted  parameter expansion and treats them specially, so
                     that characters within the single quotes  are  considered
                     quoted (this is POSIX interpretation 221).

       ccoommppaatt4422
              +o      The replacement string in double-quoted pattern substitu-
                     tion  does  not undergo quote removal, as it does in ver-
                     sions after bash-4.2.
              +o      In posix mode, single quotes are considered special  when
                     expanding  the  _w_o_r_d portion of a double-quoted parameter
                     expansion and can be used to quote  a  closing  brace  or
                     other  special character (this is part of POSIX interpre-
                     tation 221); in later versions,  single  quotes  are  not
                     special within double-quoted word expansions.

       ccoommppaatt4433
              +o      Word  expansion  errors  are  considered non-fatal errors
                     that cause the current command to  fail,  even  in  posix
                     mode  (the  default behavior is to make them fatal errors
                     that cause the shell to exit).
              +o      When  executing  a  shell  function,   the   loop   state
                     (while/until/etc.)  is not reset, so bbrreeaakk or ccoonnttiinnuuee in
                     that function will break or continue loops in the calling
                     context.  Bash-4.4 and later reset the loop state to pre-
                     vent this.

       ccoommppaatt4444
              +o      The  shell  sets  up  the  values  used  by BBAASSHH__AARRGGVV and
                     BBAASSHH__AARRGGCC so they can expand to  the  shell's  positional
                     parameters  even  if  extended  debugging mode is not en-
                     abled.
              +o      A subshell inherits loops from  its  parent  context,  so
                     bbrreeaakk  or  ccoonnttiinnuuee  will  cause  the  subshell  to exit.
                     Bash-5.0 and later reset the loop state  to  prevent  the
                     exit
              +o      Variable  assignments  preceding builtins like eexxppoorrtt and
                     rreeaaddoonnllyy that set attributes continue to affect variables
                     with the same name in the calling environment even if the
                     shell is not in posix mode.

       ccoommppaatt5500
              +o      Bash-5.1 changed the way $$RRAANNDDOOMM is generated  to  intro-
                     duce  slightly more randomness.  If the shell compatibil-
                     ity level is set to 50 or lower, it reverts to the method
                     from bash-5.0 and previous versions, so seeding the  ran-
                     dom  number generator by assigning a value to RRAANNDDOOMM will
                     produce the same sequence as in bash-5.0.
              +o      If the command hash table is empty, bash  versions  prior
                     to  bash-5.1 printed an informational message to that ef-
                     fect, even when producing output that can  be  reused  as
                     input.   Bash-5.1 suppresses that message when the --ll op-
                     tion is supplied.

       ccoommppaatt5511
              +o      The uunnsseett builtin treats attempts  to  unset  array  sub-
                     scripts  @@ and ** differently depending on whether the ar-
                     ray is indexed or associative, and  differently  than  in
                     previous versions.
              +o      Arithmetic commands ( ((((...)))) ) and the expressions in an
                     arithmetic for statement can be expanded more than once.
              +o      Expressions  used as arguments to arithmetic operators in
                     the [[[[ conditional command  can  be  expanded  more  than
                     once.
              +o      The  expressions  in  substring parameter brace expansion
                     can be expanded more than once.
              +o      The expressions in the $$((((...)))) word expansion can be ex-
                     panded more than once.
              +o      Arithmetic expressions used as indexed  array  subscripts
                     can be expanded more than once.
              +o      tteesstt  --vv,  when  given an argument of AA[[@@]], where AA is an
                     existing associative array, will return true if the array
                     has any set elements.  Bash-5.2 will look for and  report
                     on a key named @@.
              +o      The  ${_p_a_r_a_m_e_t_e_r[[::]]==_v_a_l_u_e}  word  expansion  will  return
                     _v_a_l_u_e, before any variable-specific transformations  have
                     been performed (e.g., converting to lowercase).  Bash-5.2
                     will return the final value assigned to the variable.
              +o      Parsing  command substitutions will behave as if extended
                     globbing (see the description of the sshhoopptt builtin above)
                     is enabled, so that parsing a command  substitution  con-
                     taining an extglob pattern (say, as part of a shell func-
                     tion)  will  not fail.  This assumes the intent is to en-
                     able extglob before the command is executed and word  ex-
                     pansions  are  performed.  It will fail at word expansion
                     time if extglob hasn't been enabled by the time the  com-
                     mand is executed.

       ccoommppaatt5522
              +o      The  tteesstt  builtin uses its historical algorithm to parse
                     parenthesized subexpressions when given five or more  ar-
                     guments.
              +o      If  the  --pp or --PP option is supplied to the bbiinndd builtin,
                     bbiinndd treats any arguments remaining after option process-
                     ing as bindable command names, and displays any  key  se-
                     quences  bound to those commands, instead of treating the
                     arguments as key sequences to bind.

SSEEEE AALLSSOO
       bash(1), sh(1)

GNU Bash 5.2                    2023 January 27               _B_A_S_H___B_U_I_L_T_I_N_S(1)