_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 numeric value of the following character, using the  cur-
              rent locale.

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

       ppuusshhdd [--nn] [+_n] [-_n]
       ppuusshhdd [--nn] [_d_i_r]
              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      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)
