_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, ..  searchs for it.  If the --pp  option  is  sup-
              plied,  ..   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 _p_o_s_i_x  _m_o_d_e,  it
              searches  the current directory if no file is found in PPAATTHH, but
              does not search the current directory if --pp is supplied.  If the
              ssoouurrcceeppaatthh option to the sshhoopptt builtin command is turned off,  ..
              does  not  search PPAATTHH.  If any _a_r_g_u_m_e_n_t_s are supplied, they be-
              come the positional parameters when _f_i_l_e_n_a_m_e is executed.   Oth-
              erwise  the  positional parameters are unchanged.  If the --TT op-
              tion 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
              is  retained  when .. completes.  The return status is the status
              of the last command exited within the script (0 if  no  commands
              are  executed),  and false if _f_i_l_e_n_a_m_e is not found or cannot be
              read.

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

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

       bbiinndd [--mm _k_e_y_m_a_p] [--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 set a rreeaaddlliinnee
              variable.  Each non-option argument is a command as it would ap-
              pear in a rreeaaddlliinnee initialization 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  descrip-
              tions,  output  available to be re-read is formatted as commands
              that would appear in a  rreeaaddlliinnee  initialization  file  or  that
              would  be  supplied  as  individual 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 re-read.  If arguments remain  after
                     option  processing,  bbiinndd treats them as readline 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 readline 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  re-
                     read.
              --SS     Display  rreeaaddlliinnee  key  sequences bound to macros and the
                     strings they output.
              --vv     Display rreeaaddlliinnee variable names and values in such a  way
                     that they can be re-read.
              --VV     List current rreeaaddlliinnee variable names and values.
              --ff _f_i_l_e_n_a_m_e
                     Read key bindings from _f_i_l_e_n_a_m_e.
              --qq _f_u_n_c_t_i_o_n
                     Query about which keys invoke the named _f_u_n_c_t_i_o_n.
              --uu _f_u_n_c_t_i_o_n
                     Unbind all keys bound to the named _f_u_n_c_t_i_o_n.
              --rr _k_e_y_s_e_q
                     Remove any current binding for _k_e_y_s_e_q.
              --xx _k_e_y_s_e_q[[:: ]]_s_h_e_l_l_-_c_o_m_m_a_n_d
                     Cause _s_h_e_l_l_-_c_o_m_m_a_n_d to be executed whenever _k_e_y_s_e_q is 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 quotes.  When _s_h_e_l_l_-_c_o_m_-
                     _m_a_n_d is executed, the shell sets the RREEAADDLLIINNEE__LLIINNEE  vari-
                     able  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__AARRGGUU--
                     MMEENNTT  variable.   If there was no argument, that variable
                     is not set.  If the executed command changes the value of
                     any of RREEAADDLLIINNEE__LLIINNEE, RREEAADDLLIINNEE__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 in-
                     put.

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

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

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

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

       ccdd [--LL|[--PP [--ee]]] [-@] [_d_i_r]
              Change the current directory to _d_i_r.  if _d_i_r  is  not  supplied,
              the  value of the HHOOMMEE shell variable is the default.  The vari-
              able CCDDPPAATTHH defines the search path for the directory containing
              _d_i_r: 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., If _d_i_r begins with a slash (/), then CCDDPPAATTHH  is
              not used.  The --PP option causes ccdd to use the physical directory
              structure  by  resolving symbolic links while traversing _d_i_r and
              before processing instances of _._. in _d_i_r (see also the --PP option
              to the sseett builtin command); the --LL option forces symbolic links
              to be followed by resolving the link after processing  instances
              of _._. in _d_i_r.  If _._. appears in _d_i_r, it is processed by removing
              the  immediately previous pathname component from _d_i_r, back to a
              slash or the beginning of _d_i_r.  If the  --ee  option  is  supplied
              with  --PP,  and  the current working directory cannot be success-
              fully determined after a successful directory  change,  ccdd  will
              return  an unsuccessful status.  On systems that support it, the
              --@@ option presents the extended  attributes  associated  with  a
              file  as  a directory.  An argument of -- is converted to $$OOLLDDPPWWDD
              before the directory change is attempted.  If a non-empty direc-
              tory name from CCDDPPAATTHH is used, or if -- is  the  first  argument,
              and the directory change is successful, the absolute pathname of
              the new working directory is written to the standard output.  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 ...]
              Run _c_o_m_m_a_n_d with _a_r_g_s  suppressing  the  normal  shell  function
              lookup.  Only builtin commands or commands found in the PPAATTHH are
              executed.   If the --pp option is given, the search for _c_o_m_m_a_n_d is
              performed using a default value for PPAATTHH that is  guaranteed  to
              find  all of the standard utilities.  If either the --VV or --vv op-
              tion is supplied, a description of _c_o_m_m_a_n_d is printed.   The  --vv
              option  causes  a single word indicating the command or filename
              used to invoke _c_o_m_m_a_n_d to be displayed; the --VV option produces a
              more verbose description.  If the --VV or --vv option  is  supplied,
              the  exit  status  is  0 if _c_o_m_m_a_n_d was found, and 1 if not.  If
              neither option is supplied and an error occurred or _c_o_m_m_a_n_d can-
              not be found, the exit status is 127.  Otherwise, the exit  sta-
              tus of the ccoommmmaanndd builtin is the exit status of _c_o_m_m_a_n_d.

       ccoommppggeenn [--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 sup-
              plied, ccoommppggeenn stores the generated completions 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.

              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  supplied,
              existing completion specifications are printed in a way that al-
              lows  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 com-
              mand completion; that is, completion attempted on a command  for
              which  no completion has previously been defined.  The --EE option
              indicates that other supplied options and actions  should  apply
              to  command completion; that is, completion attempted on a blank
              line.  The --II option indicates that other supplied  options  and
              actions should apply to completion on the initial non-assignment
              word  on  the line, or after a command delimiter such as ;; or ||,
              which is usually command name completion.  If  multiple  options
              are  supplied,  the --DD option takes precedence over --EE, and both
              take precedence over --II.  If any of --DD, --EE, or --II are  supplied,
              any other _n_a_m_e arguments are ignored; these completions only ap-
              ply to the case specified by the option.

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

              The return value is true unless an invalid option  is  supplied,
              an option other than --pp, --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 given, display the completion op-
              tions 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  op-
              tions  should  apply to the command completion; that is, comple-
              tion attempted on a command for which no completion  has  previ-
              ously been defined.  The --EE option indicates that other supplied
              options  should apply to command completion; that is, completion
              attempted on a blank line.  The --II option indicates  that  other
              supplied  options 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 completion.

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

       ccoonnttiinnuuee [_n]
              Resume the next iteration of the enclosing ffoorr, wwhhiillee, uunnttiill, or
              sseelleecctt loop.  If _n is specified, resume  at  the  _nth  enclosing
              loop.   _n  must be >= 1.  If _n is greater than the number of en-
              closing 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.  The --pp option will
              display the attributes and values of each _n_a_m_e.  When --pp is used
              with _n_a_m_e arguments, additional options, other than --ff  and  --FF,
              are  ignored.   When  --pp  is supplied without _n_a_m_e arguments, it
              will display the attributes and values of all  variables  having
              the attributes specified by the additional options.  If no other
              options  are  supplied with --pp, ddeeccllaarree will display the attrib-
              utes and values of all shell variables.  The --ff option will  re-
              strict  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 func-
              tion.   It  is ignored in all other cases.  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 variable 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  variables  with  the  specified  at-
              tribute or to give variables attributes:
              --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     Use function names only.
              --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 _n_a_m_es for export to subsequent commands via the  en-
                     vironment.

              Using  instead  of turns off the attribute instead, with the ex-
              ceptions that ++aa and ++AA may not be used to destroy  array  vari-
              ables  and ++rr will not remove the readonly attribute.  When used
              in a function, ddeeccllaarree and ttyyppeesseett make each _n_a_m_e local, as with
              the llooccaall command, unless the --gg option is supplied.  If a vari-
              able name is followed by =_v_a_l_u_e, the value of  the  variable  is
              set  to  _v_a_l_u_e.  When using --aa or --AA and the compound assignment
              syntax to create array variables, additional attributes  do  not
              take effect until subsequent assignments.  The return value is 0
              unless  an  invalid option is encountered, an attempt is made to
              define a function using 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  vari-
              able  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, displays the list of currently  remembered  di-
              rectories.   The default display is on a single line with direc-
              tory 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 direc-
              tory in the stack.
              --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] [_j_o_b_s_p_e_c ... | _p_i_d ... ]
              Without  options,  remove  each _j_o_b_s_p_e_c from the table of active
              jobs.  If _j_o_b_s_p_e_c is not present, and neither the --aa nor the  --rr
              option  is  supplied, the _c_u_r_r_e_n_t _j_o_b is used.  If the --hh option
              is given, each _j_o_b_s_p_e_c is not removed from  the  table,  but  is
              marked  so  that  SSIIGGHHUUPP is not sent to the job if the shell re-
              ceives a SSIIGGHHUUPP.  If no _j_o_b_s_p_e_c is supplied, the --aa option means
              to remove or mark all jobs; the --rr option without a _j_o_b_s_p_e_c  ar-
              gument restricts operation to running jobs.  The return value is
              0 unless a _j_o_b_s_p_e_c does not specify a valid job.

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

       eennaabbllee [--aa] [--ddnnppss] [--ff _f_i_l_e_n_a_m_e] [_n_a_m_e ...]
              Enable  and disable builtin shell commands.  Disabling a builtin
              allows a disk command which has the same name as a shell builtin
              to be executed without specifying a full pathname,  even  though
              the  shell  normally searches for builtins before disk commands.
              If --nn is used, each _n_a_m_e is disabled; otherwise, _n_a_m_e_s  are  en-
              abled.   For  example, to use the tteesstt binary found via the PPAATTHH
              instead of the shell builtin version, run 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.  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, if _f_i_l_e_n_a_m_e
              does  not contain a slash.  The default 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 no
              _n_a_m_e arguments are given, or if the --pp  option  is  supplied,  a
              list  of  shell builtins is printed.  With no other option argu-
              ments, the list consists of all enabled shell builtins.   If  --nn
              is  supplied, only disabled builtins are printed.  If --aa is sup-
              plied, the list printed includes all builtins, with  an  indica-
              tion  of whether or not each is enabled.  If --ss is supplied, the
              output is restricted to the POSIX _s_p_e_c_i_a_l builtins.  If  no  op-
              tions  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 ...]
              The _a_r_gs are read and concatenated together into a  single  com-
              mand.   This command is then read and executed by the shell, and
              its exit status is returned as the value of eevvaall.  If there  are
              no _a_r_g_s, or only null arguments, eevvaall returns 0.

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

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

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

       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); otherwise 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 spec-
              ified, it is set to the previous command for editing and -16 for
              listing.

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

              In the second form, _c_o_m_m_a_n_d is re-executed after  each  instance
              of  _p_a_t  is replaced by _r_e_p.  _C_o_m_m_a_n_d is interpreted the same as
              _f_i_r_s_t above.  A useful alias to use with this is 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 0 unless  an  in-
              valid  option  is  encountered  or _f_i_r_s_t or _l_a_s_t specify history
              lines out of range.  If the --ee option is  supplied,  the  return
              value is the value of the last command executed or failure if an
              error occurs with the temporary file of commands.  If the second
              form  is  used, the return status is that of the command re-exe-
              cuted, unless _c_m_d does not specify  a  valid  history  line,  in
              which case ffcc returns failure.

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

       ggeettooppttss _o_p_t_s_t_r_i_n_g _n_a_m_e [_a_r_g ...]
              ggeettooppttss  is used by shell procedures to parse positional parame-
              ters.  _o_p_t_s_t_r_i_n_g contains the option  characters  to  be  recog-
              nized;  if a character is followed by a colon, the option is ex-
              pected 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 op-
              tion requires an argument, ggeettooppttss places that argument into the
              variable OOPPTTAARRGG.  The shell does not reset OOPPTTIINNDD automatically;
              it  must  be  manually  reset  between multiple calls to ggeettooppttss
              within the same shell invocation if a new set of  parameters  is
              to be used.

              When the end of options is encountered, ggeettooppttss exits with a re-
              turn 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, _s_i_l_e_n_t error  reporting  is  used.   In
              normal  operation,  diagnostic messages are printed when invalid
              options or missing option arguments  are  encountered.   If  the
              variable  OOPPTTEERRRR  is  set  to  0, no error messages will be dis-
              played, even if the first character of _o_p_t_s_t_r_i_n_g is not a colon.

              If 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, the full pathname of the command _n_a_m_e
              is determined by searching the directories in $$PPAATTHH  and  remem-
              bered.  Any previously-remembered pathname is discarded.  If the
              --pp  option  is supplied, hhaasshh uses _f_i_l_e_n_a_m_e as the full filename
              of the command.  The --rr option causes the shell  to  forget  all
              remembered  locations.   Assigning  to  the  PPAATTHH  variable also
              clears all hashed filenames.  The --dd option causes the shell  to
              forget  the  remembered location of each _n_a_m_e.  If the --tt option
              is supplied, the full pathname to which each _n_a_m_e corresponds is
              printed.  If multiple _n_a_m_e arguments are supplied with  --tt,  the
              _n_a_m_e  is printed before the hashed full pathname.  The --ll option
              causes output to be displayed in a format that may be reused  as
              input.   If  no  arguments are given, or if only --ll is supplied,
              information about remembered commands is printed.  The  --tt,  --dd,
              and  --pp options (the options that act on the _n_a_m_e arguments) are
              mutually exclusive.  Only one will be active.  If more than  one
              is supplied, --tt has higher priority than --pp, and both are higher
              priority  than  --dd.   The return status is true unless a _n_a_m_e is
              not found or an invalid option is supplied.

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

              The return status is 0 unless no command matches _p_a_t_t_e_r_n.

       hhiissttoorryy [[_n]]
       hhiissttoorryy --cc
       hhiissttoorryy --dd _o_f_f_s_e_t
       hhiissttoorryy --dd _s_t_a_r_t-_e_n_d
       hhiissttoorryy --aannrrww [_f_i_l_e_n_a_m_e]
       hhiissttoorryy --pp _a_r_g [_a_r_g ...]
       hhiissttoorryy --ss _a_r_g [_a_r_g ...]
              With no options, display the command history list with line num-
              bers.  Lines listed with a ** have been modified.  An argument of
              _n  lists only the last _n lines.  If the shell variable HHIISSTTTTIIMMEE--
              FFOORRMMAATT is set and not null, it is used as a  format  string  for
              _s_t_r_f_t_i_m_e(3)  to display the time stamp associated with each dis-
              played history entry.  No intervening blank is  printed  between
              the  formatted  time stamp and the history line.  If _f_i_l_e_n_a_m_e is
              supplied, it is used as the name of the history  file;  if  not,
              the  value of HHIISSTTFFIILLEE is used.  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.
              --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  into the current history list.  These are lines ap-
                     pended to the history file since  the  beginning  of  the
                     current bbaasshh session.
              --rr     Read  the contents of the history file and append them to
                     the current history list.
              --ww     Write the current history list to the history file, over-
                     writing the history file's contents.
              --pp     Perform history substitution on the  following  _a_r_g_s  and
                     display  the  result  on  the  standard output.  Does not
                     store the results in the history list.  Each _a_r_g must  be
                     quoted to disable normal history expansion.
              --ss     Store  the  _a_r_g_s  in  the history list as a single entry.
                     The last command in the history list  is  removed  before
                     the _a_r_g_s are added.

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

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

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

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

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

       llooccaall [_o_p_t_i_o_n] [_n_a_m_e[=_v_a_l_u_e] ... | - ]
              For  each  argument, a local variable named _n_a_m_e is created, and
              assigned _v_a_l_u_e.  The _o_p_t_i_o_n can be any of the  options  accepted
              by ddeeccllaarree.  When llooccaall is used within a function, it causes the
              variable  _n_a_m_e  to have a visible scope restricted to that func-
              tion and its children.  If _n_a_m_e is -, the set of  shell  options
              is  made  local to the function in which llooccaall is invoked: shell
              options changed using the sseett builtin inside the function  after
              the call to llooccaall are restored to their original values when the
              function returns.  The restore is effected 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.  It is an error to use
              llooccaall when not within a function.  The return status is 0 unless
              llooccaall is used outside a function, an invalid _n_a_m_e  is  supplied,
              or _n_a_m_e is a readonly variable.

       llooggoouutt Exit a login shell.

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

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

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

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

       ppooppdd [-nn] [+_n] [-_n]
              Removes entries from the directory stack.  The elements are num-
              bered  from  0  starting  at the first directory listed by ddiirrss.
              With no arguments, ppooppdd  removes  the  top  directory  from  the
              stack, and changes to the new top directory.  Arguments, if sup-
              plied, have the following meanings:
              --nn     Suppresses  the  normal change of directory when removing
                     directories from the stack, so that only the stack is ma-
                     nipulated.
              ++_n     Removes 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     Removes 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 encoun-
              tered, the directory stack is empty, or a non-existent directory
              stack entry is specified.

              If the ppooppdd command is successful, bash 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 causes the output to be
              assigned to the variable _v_a_r rather than being  printed  to  the
              standard output.

              The  _f_o_r_m_a_t  is a character string which contains three types of
              objects: plain characters, which are simply copied  to  standard
              output,  character  escape  sequences,  which  are converted and
              copied to the standard output, and format  specifications,  each
              of  which  causes  printing of the next successive _a_r_g_u_m_e_n_t.  In
              addition to the standard _p_r_i_n_t_f(3) format characters ccssnnddiioouuxxXXee--
              EEffFFggGGaaAA, pprriinnttff interprets the following additional format spec-
              ifiers:
              %%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.  Two special argument
                     values may be used: -1 represents the current  time,  and
                     -2  represents the time the shell was invoked.  If no ar-
                     gument is specified, conversion behaves as if -1 had been
                     given.  This is an exception to the usual  pprriinnttff  behav-
                     ior.

              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.

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

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

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

              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 0 unless
              the directory stack  is  empty.   When  rotating  the  directory
              stack,  ppuusshhdd returns 0 unless the directory stack is empty or a
              non-existent directory stack element is specified.

              If the ppuusshhdd command is successful, bash 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 ...]
              One line is read from the standard input, or from the  file  de-
              scriptor _f_d supplied as an argument to the --uu option, split into
              words  as  described  in  _b_a_s_h (1) under WWoorrdd SSpplliittttiinngg, and the
              first word is assigned to the first _n_a_m_e, the second word to the
              second _n_a_m_e, and so on.  If there are more words than names, the
              remaining words and their intervening delimiters are assigned to
              the last _n_a_m_e.  If there are fewer words  read  from  the  input
              stream  than  names, the remaining names are assigned empty val-
              ues.  The characters in IIFFSS are used  to  split  the  line  into
              words  using  the  same  rules the shell uses for expansion (de-
              scribed in _b_a_s_h (1) under WWoorrdd SSpplliittttiinngg).  The backslash  char-
              acter (\\) may be used to remove any special meaning for the next
              character read and for line continuation.  Options, if supplied,
              have the following meanings:
              --aa _a_n_a_m_e
                     The words are assigned to sequential indices of the array
                     variable _a_n_a_m_e, starting at 0.  _a_n_a_m_e is unset before any
                     new  values  are  assigned.  Other _n_a_m_e arguments are ig-
                     nored.
              --dd _d_e_l_i_m
                     The first character of _d_e_l_i_m is used to terminate the in-
                     put 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.  Readline uses the current  (or  default,  if  line
                     editing  was not previously active) editing settings, but
                     uses readline'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.  Readline 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, _t_e_x_t is
                     placed into the editing buffer before editing begins.
              --nn _n_c_h_a_r_s
                     rreeaadd returns after reading _n_c_h_a_r_s characters rather  than
                     waiting for a complete line of input, but honors a delim-
                     iter  if fewer than _n_c_h_a_r_s characters are read before the
                     delimiter.
              --NN _n_c_h_a_r_s
                     rreeaadd returns  after  reading  exactly  _n_c_h_a_r_s  characters
                     rather  than waiting for a complete line of input, unless
                     EOF is encountered or rreeaadd times out.  Delimiter  charac-
                     ters  encountered  in the input are not treated specially
                     and do not cause rreeaadd to return until  _n_c_h_a_r_s  characters
                     are  read.   The result is not split on the characters in
                     IIFFSS; the intent is that the variable is assigned  exactly
                     the characters read (with the exception of backslash; see
                     the --rr option below).
              --pp _p_r_o_m_p_t
                     Display _p_r_o_m_p_t on standard error, without a trailing new-
                     line, before attempting to read any input.  The prompt is
                     displayed only if input is coming from a terminal.
              --rr     Backslash does not act as an escape character.  The back-
                     slash  is considered to be part of the line.  In particu-
                     lar, a backslash-newline pair may not then be used  as  a
                     line continuation.
              --ss     Silent mode.  If input is coming from a terminal, charac-
                     ters are not echoed.
              --tt _t_i_m_e_o_u_t
                     Cause  rreeaadd  to time out and return failure if a complete
                     line of input (or a specified number  of  characters)  is
                     not  read within _t_i_m_e_o_u_t seconds.  _t_i_m_e_o_u_t may be a deci-
                     mal number with a fractional portion following the  deci-
                     mal  point.   This  option  is  only effective if rreeaadd is
                     reading input from a terminal,  pipe,  or  other  special
                     file;  it  has no effect when reading from regular files.
                     If rreeaadd times out, rreeaadd saves any partial input read into
                     the specified variable _n_a_m_e.  If _t_i_m_e_o_u_t is 0,  rreeaadd  re-
                     turns  immediately, without trying to read any data.  The
                     exit status is 0 if input is available on  the  specified
                     file  descriptor,  or  the read will return EOF, non-zero
                     otherwise.  The exit status is greater than  128  if  the
                     timeout is exceeded.
              --uu _f_d  Read input from file descriptor _f_d.

              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, the line read, without the ending  de-
              limiter  but  otherwise  unmodified, is assigned to the variable
              RREEPPLLYY.  The exit status is zero, unless end-of-file  is  encoun-
              tered,  rreeaadd times out (in which case the status is greater than
              128), a variable assignment error (such as assigning to a  read-
              only variable) 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.  If the  --ff  option
              is  supplied,  the  functions  corresponding to the _n_a_m_e_s are so
              marked.  The --aa option restricts the variables  to  indexed  ar-
              rays;  the  --AA option restricts the variables to associative ar-
              rays.  If both options are supplied, --AA takes precedence.  If no
              _n_a_m_e arguments are given, or if the --pp  option  is  supplied,  a
              list of all readonly names is printed.  The other options may be
              used  to  restrict the output to a subset of the set of readonly
              names.  The --pp option causes output to be displayed in a  format
              that  may be reused as input.  If a variable name is followed by
              =_w_o_r_d, the value of the variable is set  to  _w_o_r_d.   The  return
              status  is 0 unless an invalid option is encountered, one of the
              _n_a_m_e_s is not a valid shell variable name, or --ff is supplied with
              a _n_a_m_e that is not a function.

       rreettuurrnn [_n]
              Causes a function to stop executing and return the value  speci-
              fied  by _n to its caller.  If _n is omitted, the return status is
              that of the last command executed in the function body.  If  rree--
              ttuurrnn is executed by a trap handler, the last command used to de-
              termine  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 exe-
              cuted by the trap handler before rreettuurrnn was invoked.  If  rreettuurrnn
              is  used outside a function, but during execution of a script by
              the ..  (ssoouurrccee) command, it causes the shell to  stop  executing
              that  script  and return either _n or the exit status of the last
              command executed within the script as the  exit  status  of  the
              script.  If _n is supplied, the return value is its least signif-
              icant  8  bits.  The return status is non-zero if rreettuurrnn is sup-
              plied a non-numeric argument, or is used outside a function  and
              not  during  execution  of a script by .. or ssoouurrccee.  Any command
              associated with the RREETTUURRNN trap is executed before execution re-
              sumes after the function or script.

       sseett [--aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [--oo _o_p_t_i_o_n_-_n_a_m_e] [----] [--] [_a_r_g ...]
       sseett [++aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [++oo _o_p_t_i_o_n_-_n_a_m_e] [----] [--] [_a_r_g ...]
       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 _p_o_s_i_x _m_o_d_e, only shell variables are listed.   The
              output  is sorted according to the current locale.  When options
              are specified, they set or unset shell  attributes.   Any  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.  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 keyword, part of the test following the
                      iiff or eelliiff reserved words, part of any command  executed
                      in  a &&&& or |||| list except the command following the fi-
                      nal &&&& or ||||, any command in a pipeline but the last, or
                      if the command's return value is being inverted with  !!.
                      If  a  compound  command other than a subshell returns a
                      non-zero status because a command failed  while  --ee  was
                      being  ignored, the shell does not exit.  A trap on EERRRR,
                      if set, is executed before the shell exits.  This option
                      applies to the shell environment and each subshell envi-
                      ronment separately (see CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT in
                      _b_a_s_h(1)), and may cause subshells to exit before execut-
                      ing 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   Change the behavior of bbaasshh  where  the  default
                              operation  differs  from  the  POSIX standard to
                              match the standard (_p_o_s_i_x _m_o_d_e).  See  SSEEEE  AALLSSOO
                              in  _b_a_s_h(1)  for  a reference to a document that
                              details how posix mode affects bash's behavior.
                      pprriivviilleeggeedd
                              Same as --pp.
                      vveerrbboossee Same as --vv.
                      vvii      Use a vi-style command line  editing  interface.
                              This also affects the editing interface used for
                              rreeaadd --ee.
                      xxttrraaccee  Same as --xx.
                      If  --oo  is  supplied with no _o_p_t_i_o_n_-_n_a_m_e, 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 $$EENNVV and
                      $$BBAASSHH__EENNVV files are not processed, shell  functions  are
                      not  inherited  from the environment, and the SSHHEELLLLOOPPTTSS,
                      BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they  ap-
                      pear  in  the environment, are ignored.  If the shell is
                      started with the effective user (group) id not equal  to
                      the  real user (group) id, and the --pp option is not sup-
                      plied, these actions are taken and the effective user id
                      is set to the real user id.  If the --pp  option  is  sup-
                      plied  at  startup,  the effective user id is not reset.
                      Turning this option off causes the  effective  user  and
                      group ids to be set to the real user and group ids.
              --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
                      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.   This  may  be
                      overridden when creating output files by using the redi-
                      rection operator >>|| instead of >>.
              --EE      If set, any trap on EERRRR is inherited by shell functions,
                      command  substitutions,  and commands executed in a sub-
                      shell environment.  The EERRRR trap is normally not  inher-
                      ited in such cases.
              --HH      Enable !!  style history substitution.  This option is on
                      by default when the shell is interactive.
              --PP      If  set,  the shell does not resolve symbolic links when
                      executing commands such as ccdd that  change  the  current
                      working  directory.   It  uses  the  physical  directory
                      structure instead.  By default, bbaasshh follows the logical
                      chain of  directories  when  performing  commands  which
                      change the current directory.
              --TT      If  set,  any traps on DDEEBBUUGG and RREETTUURRNN are inherited by
                      shell functions, command substitutions, and commands ex-
                      ecuted in a subshell environment.  The DDEEBBUUGG and  RREETTUURRNN
                      traps are normally not inherited in such cases.
              ----      If  no arguments follow this option, then the positional
                      parameters are unset.  Otherwise, the positional parame-
                      ters are set to the _a_r_gs, even if  some  of  them  begin
                      with a --.
              --       Signal  the  end of options, cause all remaining _a_r_gs to
                      be assigned to the positional parameters.  The --xx and --vv
                      options are turned off.  If there are no _a_r_gs, the posi-
                      tional parameters remain unchanged.

              The options are off by default unless otherwise noted.  Using  +
              rather  than  -  causes these options to be turned off.  The 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 true unless an invalid option is encoun-
              tered.

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

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

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

              The return status when listing options is zero if  all  _o_p_t_n_a_m_e_s
              are  enabled, non-zero otherwise.  When setting or unsetting 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.
              ccddaabbllee__vvaarrss
                      If  set,  an  argument to the ccdd builtin command that is
                      not a directory is assumed to be the name of a  variable
                      whose value is the directory to change to.
              ccddssppeellll If set, minor errors in the spelling of a directory com-
                      ponent  in  a  ccdd command will be corrected.  The errors
                      checked for are transposed characters, a missing charac-
                      ter, and one character too many.   If  a  correction  is
                      found,  the  corrected filename is printed, and the com-
                      mand proceeds.  This option is only used by  interactive
                      shells.
              cchheecckkhhaasshh
                      If set, bbaasshh checks that a command found in the hash ta-
                      ble  exists  before  trying  to execute it.  If a hashed
                      command no longer exists, a normal path search  is  per-
                      formed.
              cchheecckkjjoobbss
                      If set, bbaasshh lists the status of any stopped and running
                      jobs  before  exiting an interactive shell.  If any jobs
                      are running, this causes the exit to be deferred until a
                      second exit is attempted without an intervening  command
                      (see  JJOOBB  CCOONNTTRROOLL  in _b_a_s_h(1)).  The shell always post-
                      pones exiting if any jobs are stopped.
              cchheecckkwwiinnssiizzee
                      If set, bbaasshh checks the window size after each  external
                      (non-builtin)  command  and,  if  necessary, updates the
                      values of LLIINNEESS and CCOOLLUUMMNNSS.  This option is enabled  by
                      default.
              ccmmddhhiisstt If  set,  bbaasshh attempts to save all lines of a multiple-
                      line command in the same  history  entry.   This  allows
                      easy  re-editing of multi-line commands.  This option is
                      enabled by default, but only has an  effect  if  command
                      history  is  enabled, as described in _b_a_s_h(1) under HHIISS--
                      TTOORRYY.
              ccoommppaatt3311
              ccoommppaatt3322
              ccoommppaatt4400
              ccoommppaatt4411
              ccoommppaatt4422
              ccoommppaatt4433
              ccoommppaatt4444
              ccoommppaatt5500
                      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  readline  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  command.   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, the extended pattern matching features described
                      in _b_a_s_h(1) under PPaatthhnnaammee EExxppaannssiioonn are enabled.

              eexxttqquuoottee
                      If set, $$_s_t_r_i_n_g and $$_s_t_r_i_n_g quoting is performed  within
                      $${{_p_a_r_a_m_e_t_e_r}} expansions enclosed in double quotes.  This
                      option is enabled by default.

              ffaaiillgglloobb
                      If  set,  patterns  which fail to match filenames during
                      pathname expansion result in an expansion error.

              ffoorrccee__ffiiggnnoorree
                      If set, the suffixes  specified  by  the  FFIIGGNNOORREE  shell
                      variable  cause words to be ignored when performing word
                      completion even if the ignored words are the only possi-
                      ble completions.  See SSHHEELLLL VVAARRIIAABBLLEESS 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, the  current  locale's  collating
                      sequence  is  not taken into account, so bb will not col-
                      late between AA and  BB,  and  upper-case  and  lower-case
                      ASCII characters will collate together.

              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, a user is given  the
                      opportunity to re-edit a failed history substitution.

              hhiissttvveerriiffyy
                      If  set, and rreeaaddlliinnee is being used, the results of his-
                      tory substitution are  not  immediately  passed  to  the
                      shell  parser.   Instead,  the  resulting line is loaded
                      into the rreeaaddlliinnee editing buffer, allowing further modi-
                      fication.

              hhoossttccoommpplleettee
                      If set, and rreeaaddlliinnee is being used, bbaasshh will attempt to
                      perform hostname completion when a word containing  a  @@
                      is  being  completed  (see  CCoommpplleettiinngg under RREEAADDLLIINNEE 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 _p_o_s_i_x _m_o_d_e  is
                      enabled.

              iinntteerraaccttiivvee__ccoommmmeennttss
                      If set, allow a word beginning with ## to cause that word
                      and  all remaining characters on that line to be ignored
                      in an interactive shell (see CCOOMMMMEENNTTSS 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 will not at-
                      tempt to search the PPAATTHH for possible  completions  when
                      completion is attempted on an empty line.

              nnooccaasseegglloobb
                      If  set,  bbaasshh  matches  filenames in a case-insensitive
                      fashion when performing pathname expansion (see PPaatthhnnaammee
                      EExxppaannssiioonn 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, the programmable completion facilities (see PPrroo--
                      ggrraammmmaabbllee  CCoommpplleettiioonn in _b_a_s_h(1)) are enabled.  This op-
                      tion 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 can be used to 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 supplied.

       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.   Operator  prece-
              dence is used when there are five or more arguments.
              !! _e_x_p_r True if _e_x_p_r is false.
              (( _e_x_p_r ))
                     Returns  the value of _e_x_p_r.  This may be used to override
                     the normal precedence of operators.
              _e_x_p_r_1 -aa _e_x_p_r_2
                     True if both _e_x_p_r_1 and _e_x_p_r_2 are true.
              _e_x_p_r_1 -oo _e_x_p_r_2
                     True if either _e_x_p_r_1 or _e_x_p_r_2 is true.

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

              0 arguments
                     The expression is false.
              1 argument
                     The expression is true if and only if the argument is not
                     null.
              2 arguments
                     If the first argument is !!, the expression is true if and
                     only if the second argument is null.  If the first  argu-
                     ment  is one of the unary conditional operators listed 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.  the two-argument test using  the  second  and
                     third  arguments.  If the first argument is exactly (( and
                     the fourth argument is exactly )), the result is the  two-
                     argument  test of the second and third arguments.  Other-
                     wise, 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 _p_o_s_i_x _m_o_d_e, or if the expression is part of
              the [[[[ command, the << and >> operators sort using the current lo-
              cale.   If  the  shell is not in _p_o_s_i_x _m_o_d_e, the tteesstt and [[ com-
              mands sort lexicographically using ASCII ordering.

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

       ttrraapp [--llpp] [[_a_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 signal(s) _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 signal is reset to its
              original disposition (the value it  had  upon  entrance  to  the
              shell).   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  in-
              vokes.

              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  to
              ttrraapp  may  be used in a subshell environment (e.g., command sub-
              stitution) and, as long as they are used before ttrraapp is used  to
              change  a  signal's handling, will display the state of its par-
              ent's traps.

              The --ll option causes ttrraapp to print a list of  signal  names  and
              their  corresponding  numbers.   Each _s_i_g_s_p_e_c is either a signal
              name defined in <_s_i_g_n_a_l_._h>, or a signal  number.   Signal  names
              are case insensitive and the SSIIGG prefix is optional.

              If  a _s_i_g_s_p_e_c is EEXXIITT (0) the command _a_c_t_i_o_n is executed on exit
              from the shell.  If a _s_i_g_s_p_e_c is DDEEBBUUGG, the  command  _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 command, 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 option to the sshhoopptt builtin for de-
              tails of its effect on the DDEEBBUUGG trap.  If a _s_i_g_s_p_e_c is  RREETTUURRNN,
              the  command  _a_c_t_i_o_n is executed each time a shell function or a
              script executed with the .. or ssoouurrccee builtins  finishes  execut-
              ing.

              If  a  _s_i_g_s_p_e_c is EERRRR, the command _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 keyword, part of the test in an _i_f statement,
              part of a command executed in a &&&& or |||| list except the command
              following the final &&&& or ||||, any command in a pipeline but  the
              last,  or  if the command's return value is being inverted using
              !!.  These are the same conditions obeyed by the eerrrreexxiitt (--ee) 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 ...]
              With no options, indicate how each _n_a_m_e would be interpreted  if
              used as a command name.  If the --tt option is used, ttyyppee prints a
              string  which  is  one  of _a_l_i_a_s, _k_e_y_w_o_r_d, _f_u_n_c_t_i_o_n, _b_u_i_l_t_i_n, or
              _f_i_l_e if  _n_a_m_e  is  an  alias,  shell  reserved  word,  function,
              builtin,  or executable disk file, respectively.  If the _n_a_m_e is
              not found, then nothing is printed, and ttyyppee returns a  non-zero
              exit  status.  If the --pp option is used, ttyyppee either returns the
              name of the executable file that would  be  found  by  searching
              $$PPAATTHH  if  _n_a_m_e  were specified as a command name, 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 a command is
              hashed, --pp and --PP print the hashed value, which is not necessar-
              ily the file that appears first in PPAATTHH.  If the  --aa  option  is
              used, ttyyppee prints all of the places that contain 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  sup-
              plied 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 ccoommmmaanndd builtin.  ttyyppee re-
              turns 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 started by it, on systems that allow such  control.
              The --HH and --SS options specify that the hard or soft limit is set
              for  the  given resource.  A hard limit cannot be increased by a
              non-root user once it is set; a soft limit may be  increased  up
              to  the value of the hard limit.  If neither --HH nor --SS is speci-
              fied, both the soft and hard limits are set.  The value of _l_i_m_i_t
              can be a number in the unit specified for the resource or one of
              the special values hhaarrdd, ssoofftt, or uunnlliimmiitteedd, which stand for the
              current hard limit, the current soft limit, and  no  limit,  re-
              spectively.   If _l_i_m_i_t is omitted, the current value of the soft
              limit of the resource is printed, unless the --HH option is given.
              When more than one resource is specified,  the  limit  name  and
              unit,  if  appropriate, are printed before the value.  Other op-
              tions are interpreted as follows:
              --aa     All current limits are reported; 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 given, and the --aa option is not used, _l_i_m_i_t is the
              new value of the specified resource.  If  no  option  is  given,
              then  --ff is assumed.  Values are in 1024-byte increments, except
              for --tt, which is in seconds; --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]
              The user file-creation mask is set to _m_o_d_e.  If _m_o_d_e begins with
              a  digit,  it is interpreted as an octal number; otherwise it is
              interpreted as a symbolic mode mask similar to that accepted  by
              _c_h_m_o_d(1).   If _m_o_d_e is omitted, the current value of the mask is
              printed.  The --SS option causes the mask to be  printed  in  sym-
              bolic  form;  the  default output is an octal number.  If the --pp
              option is supplied, and _m_o_d_e is omitted, the output is in a form
              that may be reused as input.  The return status is 0 if the mode
              was successfully changed or if no _m_o_d_e  argument  was  supplied,
              and false otherwise.

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

       uunnsseett [-ffvv] [-nn] [_n_a_m_e ...]
              For  each  _n_a_m_e,  remove the corresponding variable or function.
              If the --vv option is given, each _n_a_m_e refers to a shell variable,
              and that variable is removed.  Read-only variables  may  not  be
              unset.   If  --ff  is specified, each _n_a_m_e refers to a shell func-
              tion, and the function definition is removed.  If the --nn  option
              is  supplied, and _n_a_m_e is a variable with the _n_a_m_e_r_e_f attribute,
              _n_a_m_e will be unset rather than the variable it  references.   --nn
              has  no  effect if the --ff option is supplied.  If no options are
              supplied, each _n_a_m_e refers to a variable; if there is  no  vari-
              able  by that name, a function with that name, if any, is unset.
              Each unset variable or function is removed from the  environment
              passed   to   subsequent  commands.   If  any  of  BBAASSHH__AALLIIAASSEESS,
              BBAASSHH__AARRGGVV00,  BBAASSHH__CCMMDDSS,  BBAASSHH__CCOOMMMMAANNDD,  BBAASSHH__SSUUBBSSHHEELLLL,  BBAASSHHPPIIDD,
              CCOOMMPP__WWOORRDDBBRREEAAKKSS,  DDIIRRSSTTAACCKK,  EEPPOOCCHHRREEAALLTTIIMMEE,  EEPPOOCCHHSSEECCOONNDDSS, FFUUNNCC--
              NNAAMMEE, GGRROOUUPPSS, HHIISSTTCCMMDD, LLIINNEENNOO, RRAANNDDOOMM, SSEECCOONNDDSS, or  SSRRAANNDDOOMM  are
              unset, they lose their special properties, even if they are sub-
              sequently reset.  The exit status is true unless a _n_a_m_e is read-
              only or may not be unset.

       wwaaiitt [--ffnn] [--pp _v_a_r_n_a_m_e] [_i_d ...]
              Wait for each specified child process and return its termination
              status.   Each _i_d may be a process ID or a job specification; if
              a job spec is given, all processes in that  job's  pipeline  are
              waited  for.   If  _i_d  is  not given, 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 a single job from
              the list of _i_ds or, if no _i_ds are supplied, any job, to complete
              and returns its exit status.  If none of the supplied  arguments
              is a child of the shell, or if no arguments are supplied and the
              shell  has no unwaited-for children, the exit status is 127.  If
              the --pp option is supplied, the process or job identifier of  the
              job  for  which  the  exit status is returned is assigned to the
              variable _v_a_r_n_a_m_e named by the  option  argument.   The  variable
              will  be unset initially, before any assignment.  This is useful
              only when the --nn option is supplied.  Supplying the  --ff  option,
              when  job control is enabled, forces wwaaiitt to wait for _i_d to ter-
              minate before returning its status, instead of returning when it
              changes status.  If _i_d specifies a non-existent process or  job,
              the  return  status is 127.  If wwaaiitt is interrupted by a signal,
              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 process or job waited for.

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 rhs  of  the
       regexp  matching operator quotes special regexp characters in the word,
       which is default behavior in bash-3.2 and subsequent versions).

       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 has begun deprecating older compatibility
       levels.  Eventually, the options will be removed in favor of  BBAASSHH__CCOOMM--
       PPAATT.

       Bash-5.0  was  the  final version for which there will be an individual
       shopt option for the previous version. Users should control the compat-
       ibility level with BBAASSHH__CCOOMMPPAATT.

       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  _p_o_s_i_x 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      the  shell does not print a warning message if an attempt
                     is made to use a quoted compound assignment as  an  argu-
                     ment  to declare (e.g., declare -a foo=(1 2)). Later ver-
                     sions warn that this usage is deprecated
              +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 enabled
              +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 compatibility
                     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)
