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    Command:

    break

    
           enable,  eval,  exec, exit, export, false, fc, fg, getopts, hash, help,
           history, jobs, kill, let, local, logout, mapfile, popd, printf,  pushd,
           pwd,  read, readonly, return, set, shift, shopt, source, suspend, test,
           times, trap, true, type, typeset, ulimit, umask, unalias, unset, wait -
           bash built-in commands, see bash(1)
    
    
    

    BASH BUILTIN COMMANDS

           Unless otherwise noted, each builtin command documented in this section
           as accepting options preceded by - accepts -- to signify the end of the
           options.   The  :, true, false, and test builtins do not accept options
           and do not treat -- specially.  The exit, logout, break, continue, let,
           and  shift builtins accept and process arguments beginning with - with-
           out requiring --.  Other builtins that accept  arguments  but  are  not
           specified  as accepting options interpret arguments beginning with - as
           invalid options and require -- to prevent this interpretation.
           : [arguments]
                  No effect; the command does nothing beyond  expanding  arguments
                  and  performing any specified redirections.  A zero exit code is
                  returned.
    
            .  filename [arguments]
           source filename [arguments]
                  Read and execute commands from filename  in  the  current  shell
                  environment  and return the exit status of the last command exe-
                  cuted from filename.  If filename does not contain a slash, file
                  names  in  PATH  are used to find the directory containing file-
                  name.  The file searched for in PATH  need  not  be  executable.
                  When  bash  is  not  in  posix  mode,  the  current directory is
                  searched if no file is found in PATH.  If the sourcepath  option
                  to  the  shopt  builtin  command  is turned off, the PATH is not
                  searched.  If any arguments are supplied, they become the  posi-
                  tional  parameters  when  filename  is  executed.  Otherwise the
                  positional parameters are unchanged.  The return status  is  the
                  status  of  the  last  command exited within the script (0 if no
                  commands are executed), and false if filename is  not  found  or
                  cannot be read.
    
           alias [-p] [name[=value] ...]
                  Alias with no arguments or with the -p option prints the list of
                  aliases in the form alias name=value on standard  output.   When
                  arguments  are supplied, an alias is defined for each name whose
                  value is given.  A trailing space in  value causes the next word
                  to be checked for alias substitution when the alias is expanded.
                  For each name in the argument list for which no  value  is  sup-
                  plied,  the  name  and  value  of  the  alias is printed.  Alias
                  returns true unless a name is given for which no alias has  been
                  defined.
    
           bg [jobspec ...]
                  Resume  each  suspended  job jobspec in the background, as if it
                  had been started with &.  If jobspec is not present, the shell's
                  notion  of the current job is used.  bg jobspec returns 0 unless
                  as a separate argument; e.g.,  '"\C-x\C-r":  re-read-init-file'.
                  Options, if supplied, have the following meanings:
                  -m keymap
                         Use keymap as the keymap to be affected by the subsequent
                         bindings.  Acceptable keymap names are emacs, emacs-stan-
                         dard,  emacs-meta,  emacs-ctlx,  vi, vi-move, vi-command,
                         and vi-insert.  vi is equivalent to vi-command; emacs  is
                         equivalent to emacs-standard.
                  -l     List the names of all readline functions.
                  -p     Display  readline  function  names and bindings in such a
                         way that they can be re-read.
                  -P     List current readline function names and bindings.
                  -s     Display readline key sequences bound to  macros  and  the
                         strings  they  output  in such a way that they can be re-
                         read.
                  -S     Display readline key sequences bound to  macros  and  the
                         strings they output.
                  -v     Display  readline variable names and values in such a way
                         that they can be re-read.
                  -V     List current readline variable names and values.
                  -f filename
                         Read key bindings from filename.
                  -q function
                         Query about which keys invoke the named function.
                  -u function
                         Unbind all keys bound to the named function.
                  -r keyseq
                         Remove any current binding for keyseq.
                  -x keyseq:shell-command
                         Cause shell-command to be  executed  whenever  keyseq  is
                         entered.   When shell-command is executed, the shell sets
                         the READLINE_LINE variable to the contents of  the  read-
                         line  line  buffer and the READLINE_POINT variable to the
                         current location of the insertion point.  If the executed
                         command  changes  the  value  of  READLINE_LINE  or READ-
                         LINE_POINT, those new values will  be  reflected  in  the
                         editing state.
    
                  The  return value is 0 unless an unrecognized option is given or
                  an error occurred.
    
           break [n]
                  Exit from within a for, while, until, or select loop.  If  n  is
                  specified, break n levels.  n must be >= 1.  If n is greater than
                  the number of enclosing loops, all enclosing loops  are  exited.
                  The  return  value  is  non-zero when n is <= 0; Otherwise, break
                  returns 0 value.
    
           builtin shell-builtin [arguments]
                  Execute the specified shell builtin, passing it  arguments,  and
                  return its exit status.  This is useful when defining a function
                  whose name is the same as a shell builtin, retaining  the  func-
                  routine call or expr does not correspond to a valid position  in
                  the call stack.
    
           cd [-L|-P] [dir]
                  Change  the  current directory to dir.  The variable HOME is the
                  default dir.  The variable CDPATH defines the  search  path  for
                  the  directory  containing  dir.  Alternative directory names in
                  CDPATH are separated by a colon (:).  A null directory  name  in
                  CDPATH  is  the  same as the current directory, i.e., ''.''.  If
                  dir begins with a slash (/), then CDPATH is  not  used.  The  -P
                  option  says  to use the physical directory structure instead of
                  following symbolic links (see also the  -P  option  to  the  set
                  builtin command); the -L option forces symbolic links to be fol-
                  lowed.  An argument of - is equivalent to $OLDPWD.   If  a  non-
                  empty  directory  name from CDPATH is used, or if - is the first
                  argument, and the directory change is successful,  the  absolute
                  pathname of the new working directory is written to the standard
                  output.  The return value is true if the directory was  success-
                  fully changed; false otherwise.
    
           command [-pVv] command [arg ...]
                  Run  command  with  args  suppressing  the normal shell function
                  lookup. Only builtin commands or commands found in the PATH  are
                  executed.   If the -p option is given, the search for command is
                  performed using a default value for PATH that is  guaranteed  to
                  find  all  of  the  standard  utilities.  If either the -V or -v
                  option is supplied, a description of command is printed.  The -v
                  option  causes a single word indicating the command or file name
                  used to invoke command to be displayed; the -V option produces a
                  more  verbose  description.  If the -V or -v option is supplied,
                  the exit status is 0 if command was found, and  1  if  not.   If
                  neither option is supplied and an error occurred or command can-
                  not be found, the exit status is 127.  Otherwise, the exit  sta-
                  tus of the command builtin is the exit status of command.
    
           compgen [option] [word]
                  Generate  possible  completion matches for word according to the
                  options, which may  be  any  option  accepted  by  the  complete
                  builtin  with  the exception of -p and -r, and write the matches
                  to the standard output.  When using the -F or  -C  options,  the
                  various  shell  variables  set  by  the  programmable completion
                  facilities, while available, will not have useful values.
    
                  The matches will be generated in the same way  as  if  the  pro-
                  grammable  completion  code  had  generated them directly from a
                  completion specification with the same flags.  If word is speci-
                  fied, only those completions matching word will be displayed.
    
                  The  return  value is true unless an invalid option is supplied,
                  or no matches were generated.
    
           complete [-abcdefgjksuv] [-o comp-option] [-DE] [-A action]  [-G  glob-
                  attempted on a blank line.
    
                  The  process  of  applying  these completion specifications when
                  word completion is  attempted  is  described  above  under  Pro-
                  grammable Completion.
    
                  Other  options,  if specified, have the following meanings.  The
                  arguments to the -G, -W, and -X options (and, if necessary,  the
                  -P  and -S options) should be quoted to protect them from expan-
                  sion before the complete builtin is invoked.
                  -o comp-option
                          The comp-option controls several aspects  of  the  comp-
                          spec's  behavior beyond the simple generation of comple-
                          tions.  comp-option may be one of:
                          bashdefault
                                  Perform the rest of the default bash completions
                                  if the compspec generates no matches.
                          default Use  readline's  default  filename completion if
                                  the compspec generates no matches.
                          dirnames
                                  Perform directory name completion if  the  comp-
                                  spec generates no matches.
                          filenames
                                  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.
                          nospace Tell  readline  not  to  append  a  space   (the
                                  default)  to  words  completed at the end of the
                                  line.
                          plusdirs
                                  After any matches defined by  the  compspec  are
                                  generated,    directory   name   completion   is
                                  attempted and  any  matches  are  added  to  the
                                  results of the other actions.
                  -A action
                          The  action  may  be  one of the following to generate a
                          list of possible completions:
                          alias   Alias names.  May also be specified as -a.
                          arrayvar
                                  Array variable names.
                          binding Readline key binding names.
                          builtin Names of shell builtin commands.   May  also  be
                                  specified as -b.
                          command Command names.  May also be specified as -c.
                          directory
                                  Directory names.  May also be specified as -d.
                          disabled
                                  Names of disabled shell builtins.
                          enabled Names of enabled shell builtins.
                                  -k.
                          running Names of running jobs, if job control is active.
                          service Service names.  May also be specified as -s.
                          setopt  Valid arguments for the -o  option  to  the  set
                                  builtin.
                          shopt   Shell  option  names  as  accepted  by the shopt
                                  builtin.
                          signal  Signal names.
                          stopped Names of stopped jobs, if job control is active.
                          user    User names.  May also be specified as -u.
                          variable
                                  Names of all shell variables.  May also be spec-
                                  ified as -v.
                  -G globpat
                          The pathname expansion pattern globpat  is  expanded  to
                          generate the possible completions.
                  -W wordlist
                          The  wordlist  is  split using the characters in the IFS
                          special variable as delimiters, and each resultant  word
                          is  expanded.   The possible completions are the members
                          of the resultant list which match the  word  being  com-
                          pleted.
                  -C command
                          command  is  executed in a subshell environment, and its
                          output is used as the possible completions.
                  -F function
                          The shell function function is executed in  the  current
                          shell  environment.  When it finishes, the possible com-
                          pletions are retrieved from the value of  the  COMPREPLY
                          array variable.
                  -X filterpat
                          filterpat  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 filterpat is removed from the  list.
                          A  leading  !  in filterpat negates the pattern; in this
                          case, any completion not matching filterpat is  removed.
                  -P prefix
                          prefix  is  added at the beginning of each possible com-
                          pletion after all other options have been applied.
                  -S suffix
                          suffix is appended to each possible completion after all
                          other options have been applied.
    
                  The  return  value is true unless an invalid option is supplied,
                  an option other than -p or -r is supplied without a  name  argu-
                  ment,  an  attempt  is made to remove a completion specification
                  for a name for which no specification exists, or an error occurs
                  adding a completion specification.
    
           compopt [-o option] [-DE] [+o option] [name]
                  Modify  completion  options  for  each  name  according  to  the
    
           continue [n]
                  Resume the next iteration of the enclosing for, while, until, or
                  select loop.  If n is specified, resume  at  the  nth  enclosing
                  loop.   n  must  be  >=  1.   If  n is greater than the number of
                  enclosing loops, the  last  enclosing  loop  (the  ''top-level''
                  loop) is resumed.  When continue is executed inside of loop, the
                  return value is non-zero when n  is  <=  0;  Otherwise,  continue
                  returns  0 value. When continue is executed outside of loop, the
                  return value is 0.
    
           declare [-aAfFilrtux] [-p] [name[=value] ...]
           typeset [-aAfFilrtux] [-p] [name[=value] ...]
                  Declare variables and/or give them attributes.  If no names  are
                  given  then display the values of variables.  The -p option will
                  display the attributes and values of each name.  When -p is used
                  with name arguments, additional options are ignored.  When -p is
                  supplied without name 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
                  -p,  declare will display the attributes and values of all shell
                  variables.  The -f option will restrict  the  display  to  shell
                  functions.  The -F option inhibits the display of function defi-
                  nitions; only the function name and attributes are printed.   If
                  the  extdebug  shell  option  is enabled using shopt, the source
                  file name and line number where the function is defined are dis-
                  played  as  well.   The  -F  option  implies  -f.  The following
                  options can be used to restrict output  to  variables  with  the
                  specified attribute or to give variables attributes:
                  -a     Each  name  is  an  indexed  array  variable  (see Arrays
                         above).
                  -A     Each name is an associative array  variable  (see  Arrays
                         above).
                  -f     Use function names only.
                  -i     The variable is treated as an integer; arithmetic evalua-
                         tion (see ARITHMETIC EVALUATION above) is performed  when
                         the variable is assigned a value.
                  -l     When  the  variable  is  assigned a value, all upper-case
                         characters are converted to lower-case.   The  upper-case
                         attribute is disabled.
                  -r     Make names readonly.  These names cannot then be assigned
                         values by subsequent assignment statements or unset.
                  -t     Give each name the  trace  attribute.   Traced  functions
                         inherit  the  DEBUG  and  RETURN  traps  from the calling
                         shell.  The trace attribute has no  special  meaning  for
                         variables.
                  -u     When  the  variable  is  assigned a value, all lower-case
                         characters are converted to upper-case.   The  lower-case
                         attribute is disabled.
                  -x     Mark  names  for  export  to  subsequent commands via the
                         environment.
    
                  tent function with -f.
    
           dirs [+n] [-n] [-cplv]
                  Without options,  displays  the  list  of  currently  remembered
                  directories.   The  default  display  is  on  a single line with
                  directory names separated by spaces.  Directories are  added  to
                  the  list  with  the  pushd  command;  the  popd command removes
                  entries from the list.
                  +n     Displays the nth entry counting from the left of the list
                         shown by dirs when invoked without options, starting with
                         zero.
                  -n     Displays the nth entry counting from  the  right  of  the
                         list shown by dirs when invoked without options, starting
                         with zero.
                  -c     Clears  the  directory  stack  by  deleting  all  of  the
                         entries.
                  -l     Produces  a  longer  listing;  the default listing format
                         uses a tilde to denote the home directory.
                  -p     Print the directory stack with one entry per line.
                  -v     Print the directory stack with one entry per  line,  pre-
                         fixing each entry with its index in the stack.
    
                  The  return value is 0 unless an invalid option is supplied or n
                  indexes beyond the end of the directory stack.
    
           disown [-ar] [-h] [jobspec ...]
                  Without options, each jobspec  is  removed  from  the  table  of
                  active  jobs.   If jobspec is not present, and neither -a nor -r
                  is supplied, the shell's notion of the current job is used.   If
                  the -h option is given, each jobspec is not removed from the ta-
                  ble, but is marked so that SIGHUP is not sent to the job if  the
                  shell  receives a SIGHUP.  If no jobspec is present, and neither
                  the -a nor the -r option is supplied, the current job  is  used.
                  If no jobspec is supplied, the -a option means to remove or mark
                  all jobs; the -r option without  a  jobspec  argument  restricts
                  operation  to running jobs.  The return value is 0 unless a job-
                  spec does not specify a valid job.
    
           echo [-neE] [arg ...]
                  Output the args, separated by spaces,  followed  by  a  newline.
                  The return status is always 0.  If -n is specified, the trailing
                  newline is suppressed.  If the -e option is  given,  interpreta-
                  tion  of  the following backslash-escaped characters is enabled.
                  The -E option disables the interpretation of these escape  char-
                  acters,  even  on systems where they are interpreted by default.
                  The xpg_echo shell option may be used to  dynamically  determine
                  whether  or not echo expands these escape characters by default.
                  echo does not interpret -- to mean the  end  of  options.   echo
                  interprets the following escape sequences:
                  \a     alert (bell)
                  \b     backspace
                  \c     suppress further output
                  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  -n  is  used,  each  name  is disabled; otherwise, names are
                  enabled.  For example, to use the test binary found via the PATH
                  instead  of  the  shell builtin version, run ''enable -n test''.
                  The -f option means to load the new builtin  command  name  from
                  shared object filename, on systems that support dynamic loading.
                  The -d option will delete a builtin previously loaded  with  -f.
                  If no name arguments are given, or if the -p 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 -n
                  is supplied, only disabled builtins are printed.  If -a is  sup-
                  plied,  the  list printed includes all builtins, with an indica-
                  tion of whether or not each is enabled.  If -s is supplied,  the
                  output  is restricted to the POSIX special builtins.  The return
                  value is 0 unless a name is not a shell builtin or there  is  an
                  error loading a new builtin from a shared object.
    
           eval [arg ...]
                  The  args  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 eval.  If there are
                  no args, or only null arguments, eval returns 0.
    
           exec [-cl] [-a name] [command [arguments]]
                  If command is specified, it replaces the shell.  No new  process
                  is  created.  The arguments become the arguments to command.  If
                  the -l option is supplied, the shell places a dash at the begin-
                  ning  of  the  zeroth  argument passed to command.  This is what
                  login(1) does.  The -c option causes command to be executed with
                  an  empty environment.  If -a is supplied, the shell passes name
                  as the zeroth argument to the executed command.  If command can-
                  not  be executed for some reason, a non-interactive shell exits,
                  unless the shell option execfail is enabled, in  which  case  it
                  returns  failure.   An  interactive shell returns failure if the
                  file cannot be executed.  If command is not specified, any redi-
                  rections take effect in the current shell, and the return status
                  is 0.  If there is a redirection error, the return status is  1.
    
           exit [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
                  EXIT is executed before the shell terminates.
    
           export [-fn] [name[=word]] ...
           export -p
                  The  supplied names are marked for automatic export to the envi-
                  ronment of subsequently executed commands.  If the -f option  is
                  given,  the names refer to functions.  If no names are given, or
                  if the -p option is supplied, a  list  of  all  names  that  are
                  exported  in  this  shell  is printed.  The -n option causes the
                  rent command number).  If last is not specified it is set to the
                  current  command  for  listing (so that ''fc -l -10'' prints the
                  last 10 commands) and to first otherwise.  If first is not spec-
                  ified  it is set to the previous command for editing and -16 for
                  listing.
    
                  The -n option suppresses the command numbers when listing.   The
                  -r  option reverses the order of the commands.  If the -l option
                  is given, the commands are listed on  standard  output.   Other-
                  wise,  the editor given by ename is invoked on a file containing
                  those commands.  If ename is not given, the value of the  FCEDIT
                  variable  is used, and the value of EDITOR if FCEDIT is not set.
                  If neither variable is set, is used.  When editing is  complete,
                  the edited commands are echoed and executed.
    
                  In  the  second form, command is re-executed after each instance
                  of pat is replaced by rep.  A useful alias to use with  this  is
                  ''r="fc  -s"'',  so  that  typing ''r cc'' runs the last command
                  beginning with ''cc'' and typing ''r'' re-executes the last com-
                  mand.
    
                  If  the  first  form  is  used,  the return value is 0 unless an
                  invalid option is encountered or first or last  specify  history
                  lines  out  of  range.  If the -e 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  cmd  does  not  specify a valid history line, in
                  which case fc returns failure.
    
           fg [jobspec]
                  Resume jobspec in the foreground, and make it the  current  job.
                  If jobspec is not present, the shell's notion of the current job
                  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 jobspec does not spec-
                  ify  a  valid  job  or  jobspec specifies a job that was started
                  without job control.
    
           getopts optstring name [args]
                  getopts is used by shell procedures to parse positional  parame-
                  ters.   optstring  contains  the  option characters to be recog-
                  nized; if a character is followed by  a  colon,  the  option  is
                  expected  to have an argument, which should be separated from it
                  by white space.  The colon and question mark characters may  not
                  be  used as option characters.  Each time it is invoked, getopts
                  places the next option in the shell variable name,  initializing
                  name if it does not exist, and the index of the next argument to
                  be processed into the variable OPTIND.  OPTIND is initialized to
                  1  each  time  the  shell or a shell script is invoked.  When an
                  option requires an argument, getopts places that  argument  into
                  the  variable OPTARG.  The shell does not reset OPTIND automati-
                  options or missing option arguments  are  encountered.   If  the
                  variable  OPTERR  is  set  to  0, no error messages will be dis-
                  played, even if the first character of optstring is not a colon.
    
                  If an invalid option is seen, getopts places ? into name and, if
                  not silent, prints an  error  message  and  unsets  OPTARG.   If
                  getopts  is  silent,  the  option  character  found is placed in
                  OPTARG and no diagnostic message is printed.
    
                  If a required argument is not found, and getopts is not  silent,
                  a  question  mark  (?) is placed in name, OPTARG is unset, and a
                  diagnostic message is printed.  If getopts  is  silent,  then  a
                  colon  (:)  is  placed  in  name and OPTARG is set to the option
                  character found.
    
                  getopts returns true if an option, specified or unspecified,  is
                  found.  It returns false if the end of options is encountered or
                  an error occurs.
    
           hash [-lr] [-p filename] [-dt] [name]
                  For each name, the full file name of the command  is  determined
                  by searching the directories in $PATH and remembered.  If the -p
                  option is supplied, no path search is performed, and filename is
                  used as the full file name of the command.  The -r option causes
                  the shell to forget all remembered  locations.   The  -d  option
                  causes the shell to forget the remembered location of each name.
                  If the -t option is supplied, the full pathname  to  which  each
                  name  corresponds  is  printed.   If multiple name arguments are
                  supplied with -t, the name is printed  before  the  hashed  full
                  pathname.  The -l option causes output to be displayed in a for-
                  mat that may be reused as input.  If no arguments are given,  or
                  if only -l is supplied, information about remembered commands is
                  printed.  The return status is true unless a name is  not  found
                  or an invalid option is supplied.
    
           help [-dms] [pattern]
                  Display  helpful information about builtin commands.  If pattern
                  is specified, help gives detailed help on all commands  matching
                  pattern;  otherwise  help for all the builtins and shell control
                  structures is printed.
                  -d     Display a short description of each pattern
                  -m     Display the description of each pattern in a manpage-like
                         format
                  -s     Display only a short usage synopsis for each pattern
           The return status is 0 unless no command matches pattern.
    
           history [n]
           history -c
           history -d offset
           history -anrw [filename]
           history -p arg [arg ...]
           history -s arg [arg ...]
                         since  the  beginning of the current bash session) to the
                         history file.
                  -n     Read the history lines not already read from the  history
                         file  into  the  current  history  list.  These are lines
                         appended to the history file since the beginning  of  the
                         current bash session.
                  -r     Read the contents of the history file and use them as the
                         current history.
                  -w     Write the current history to the history file,  overwrit-
                         ing the history file's contents.
                  -p     Perform  history  substitution  on the following args and
                         display the result on  the  standard  output.   Does  not
                         store  the results in the history list.  Each arg must be
                         quoted to disable normal history expansion.
                  -s     Store the args in the history list  as  a  single  entry.
                         The  last  command  in the history list is removed before
                         the args are added.
    
                  If the HISTTIMEFORMAT variable is set, the time  stamp  informa-
                  tion  associated  with each history entry is written to the his-
                  tory file, marked with the history comment character.  When  the
                  history  file  is read, lines beginning with the history comment
                  character followed immediately by a  digit  are  interpreted  as
                  timestamps for the previous history line.  The return value is 0
                  unless an invalid option is encountered, an error  occurs  while
                  reading  or  writing the history file, an invalid offset is sup-
                  plied as an argument to -d, or the history expansion supplied as
                  an argument to -p fails.
    
           jobs [-lnprs] [ jobspec ... ]
           jobs -x command [ args ... ]
                  The first form lists the active jobs.  The options have the fol-
                  lowing meanings:
                  -l     List process IDs in addition to the normal information.
                  -p     List only the process  ID  of  the  job's  process  group
                         leader.
                  -n     Display  information  only  about  jobs that have changed
                         status since the user was last notified of their  status.
                  -r     Restrict output to running jobs.
                  -s     Restrict output to stopped jobs.
    
                  If  jobspec  is given, output is restricted to information about
                  that job.  The return status is 0 unless an  invalid  option  is
                  encountered or an invalid jobspec is supplied.
    
                  If the -x option is supplied, jobs replaces any jobspec found in
                  command or args with the corresponding  process  group  ID,  and
                  executes command passing it args, returning its exit status.
    
           kill [-s sigspec | -n signum | -sigspec] [pid | jobspec] ...
           kill -l [sigspec | exit_status]
                  Send  the  signal  named  by  sigspec or signum to the processes
                  METIC  EVALUATION  above).   If the last arg evaluates to 0, let
                  returns 1; 0 is returned otherwise.
    
           local [option] [name[=value] ...]
                  For each argument, a local variable named name is  created,  and
                  assigned  value.   The option can be any of the options accepted
                  by declare.  When local is used within a function, it causes the
                  variable  name  to have a visible scope restricted to that func-
                  tion and its children.  With no operands, local writes a list of
                  local  variables  to the standard output.  It is an error to use
                  local when not within a function.  The return status is 0 unless
                  local  is  used outside a function, an invalid name is supplied,
                  or name is a readonly variable.
    
           logout Exit a login shell.
    
           mapfile [-n count] [-O origin] [-s count] [-t] [-u  fd]  [-C  callback]
           [-c quantum] [array]
           readarray [-n count] [-O origin] [-s count] [-t] [-u fd] [-C  callback]
           [-c quantum] [array]
                  Read lines from the standard input into the indexed array  vari-
                  able  array, or from file descriptor fd if the -u option is sup-
                  plied.  The variable MAPFILE is the default array.  Options,  if
                  supplied, have the following meanings:
                  -n     Copy  at  most count lines.  If count is 0, all lines are
                         copied.
                  -O     Begin assigning to array at index  origin.   The  default
                         index is 0.
                  -s     Discard the first count lines read.
                  -t     Remove a trailing newline from each line read.
                  -u     Read  lines  from file descriptor fd instead of the stan-
                         dard input.
                  -C     Evaluate callback each time quantum lines are read.   The
                         -c option specifies quantum.
                  -c     Specify  the  number  of  lines read between each call to
                         callback.
    
                  If -C is specified without -c,  the  default  quantum  is  5000.
                  When callback is evaluated, it is supplied the index of the next
                  array element to be assigned as an additional  argument.   call-
                  back  is  evaluated  after the line is read but before the array
                  element is assigned.
    
                  If not supplied with an  explicit  origin,  mapfile  will  clear
                  array before assigning to it.
    
                  mapfile  returns successfully unless an invalid option or option
                  argument is supplied, array is invalid or  unassignable,  or  if
                  array is not an indexed array.
    
           popd [-n] [+n] [-n]
                  Removes  entries  from  the directory stack.  With no arguments,
                  If the popd command is successful, a dirs is performed as  well,
                  and  the  return  status is 0.  popd returns false if an invalid
                  option is encountered, the directory stack is empty, a non-exis-
                  tent directory stack entry is specified, or the directory change
                  fails.
    
           printf [-v var] format [arguments]
                  Write the formatted arguments to the standard output  under  the
                  control  of  the format.  The format is a character string which
                  contains three types of objects:  plain  characters,  which  are
                  simply  copied  to  standard output, character escape sequences,
                  which are converted and copied to the standard output, and  for-
                  mat  specifications,  each  of which causes printing of the next
                  successive argument.  In addition to the standard printf(1) for-
                  mats,  %b  causes printf to expand backslash escape sequences in
                  the corresponding argument (except that  \c  terminates  output,
                  backslashes in \', \", and \? are not removed, and octal escapes
                  beginning with \0 may contain up to four digits), and %q  causes
                  printf to output the corresponding argument in a format that can
                  be reused as shell input.
    
                  The -v option causes the output to be assigned to  the  variable
                  var rather than being printed to the standard output.
    
                  The  format  is  reused as necessary to consume all of the argu-
                  ments.  If the format requires more arguments than are supplied,
                  the  extra  format  specifications  behave as if a zero value or
                  null string, as appropriate,  had  been  supplied.   The  return
                  value is zero on success, non-zero on failure.
    
           pushd [-n] [+n] [-n]
           pushd [-n] [dir]
                  Adds  a  directory to the top of the directory stack, or rotates
                  the stack, making the new top of the stack the  current  working
                  directory.  With no arguments, exchanges the top two directories
                  and returns 0, unless the directory stack is empty.   Arguments,
                  if supplied, have the following meanings:
                  -n     Suppresses  the  normal  change  of directory when adding
                         directories to the stack,  so  that  only  the  stack  is
                         manipulated.
                  +n     Rotates  the  stack  so  that the nth directory (counting
                         from the left of the list shown by  dirs,  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 dirs,  starting  with
                         zero) is at the top.
                  dir    Adds dir to the directory stack at the top, making it the
                         new current working directory.
    
                  If the pushd command is successful, a dirs is performed as well.
                  If  the first form is used, pushd returns 0 unless the cd to dir
                  fails.  With the second form, pushd returns 0 unless the  direc-
    
           prompt] [-t timeout] [-u fd] [name ...]
                  One  line  is  read  from  the  standard input, or from the file
                  descriptor fd supplied as an argument to the -u option, and  the
                  first word is assigned to the first name, the second word to the
                  second name, and so on, with leftover words and their  interven-
                  ing  separators  assigned  to the last name.  If there are fewer
                  words read from the input stream than names, the remaining names
                  are  assigned  empty  values.  The characters in IFS are used to
                  split the line into words.  The backslash character (\)  may  be
                  used  to  remove any special meaning for the next character read
                  and for line continuation.  Options, if supplied, have the  fol-
                  lowing meanings:
                  -a aname
                         The words are assigned to sequential indices of the array
                         variable aname, starting at 0.  aname is unset before any
                         new  values  are  assigned.   Other  name  arguments  are
                         ignored.
                  -d delim
                         The first character of delim is  used  to  terminate  the
                         input line, rather than newline.
                  -e     If the standard input is coming from a terminal, readline
                         (see READLINE above) is used to obtain the  line.   Read-
                         line  uses  the  current (or default, if line editing was
                         not previously active) editing settings.
                  -i text
                         If readline is being used  to  read  the  line,  text  is
                         placed into the editing buffer before editing begins.
                  -n nchars
                         read  returns after reading nchars characters rather than
                         waiting for a complete line of input, but honor a  delim-
                         iter  if fewer than nchars characters are read before the
                         delimiter.
                  -N nchars
                         read returns  after  reading  exactly  nchars  characters
                         rather  than waiting for a complete line of input, unless
                         EOF is encountered or read times out.  Delimiter  charac-
                         ters  encountered  in the input are not treated specially
                         and do not cause read to return until  nchars  characters
                         are read.
                  -p prompt
                         Display prompt 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.
                  -r     Backslash does not act as an escape character.  The back-
                         slash is considered to be part of the line.  In  particu-
                         lar,  a  backslash-newline pair may not be used as a line
                         continuation.
                  -s     Silent mode.  If input is coming from a terminal, charac-
                         ters are not echoed.
                  -t timeout
                         Cause  read  to time out and return failure if a complete
                         line of input is not read within timeout seconds.   time-
    
                  the argument to -u.
    
           readonly [-aApf] [name[=word] ...]
                  The given names are marked readonly; the values of  these  names
                  may  not  be changed by subsequent assignment.  If the -f option
                  is supplied, the functions corresponding to  the  names  are  so
                  marked.   The  -a  option  restricts  the  variables  to indexed
                  arrays; the -A option restricts  the  variables  to  associative
                  arrays.   If no name arguments are given, or if the -p option is
                  supplied, a list of all  readonly  names  is  printed.   The  -p
                  option  causes  output  to  be displayed in a format that may be
                  reused as input.  If a variable name is followed by  =word,  the
                  value  of  the  variable is set to word.  The return status is 0
                  unless an invalid option is encountered, one of the names is not
                  a  valid shell variable name, or -f is supplied with a name that
                  is not a function.
    
           return [n]
                  Causes a function to exit with the return value specified by  n.
                  If  n  is omitted, the return status is that of the last command
                  executed in the function body.  If used outside a function,  but
                  during  execution  of  a  script  by the .  (source) command, it
                  causes the shell to stop executing that script and return either
                  n  or  the  exit  status of the last command executed within the
                  script as the exit status of the  script.   If  used  outside  a
                  function  and  not during execution of a script by ., the return
                  status is false.  Any command associated with the RETURN trap is
                  executed  before execution resumes after the function or script.
    
           set [--abefhkmnptuvxBCEHPT] [-o option] [arg ...]
           set [+abefhkmnptuvxBCEHPT] [+o option] [arg ...]
                  Without options, the name and value of each shell  variable  are
                  displayed in a format that can be reused as input for setting or
                  resetting the currently-set variables.  Read-only variables can-
                  not  be  reset.  In posix mode, only shell variables are listed.
                  The output is sorted according  to  the  current  locale.   When
                  options  are specified, they set or unset shell attributes.  Any
                  arguments remaining after option processing are treated as  val-
                  ues for the positional parameters and are assigned, in order, to
                  $1, $2, ...  $n.  Options,  if  specified,  have  the  following
                  meanings:
                  -a      Automatically  mark  variables  and  functions which are
                          modified or created for export  to  the  environment  of
                          subsequent commands.
                  -b      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.
                  -e      Exit  immediately  if a pipeline (which may consist of a
                          single simple command),  a subshell command enclosed  in
                          parentheses,  or one of the commands executed as part of
                          a command list enclosed by  braces  (see  SHELL  GRAMMAR
                          above) exits with a non-zero status.  The shell does not
                          for execution.  This is enabled by default.
                  -k      All arguments in the form of assignment  statements  are
                          placed  in the environment for a command, not just those
                          that precede the command name.
                  -m      Monitor mode.  Job control is enabled.  This  option  is
                          on  by  default  for  interactive shells on systems that
                          support it (see JOB  CONTROL  above).   Background  pro-
                          cesses  run  in a separate process group and a line con-
                          taining their exit status is printed upon their  comple-
                          tion.
                  -n      Read commands but do not execute them.  This may be used
                          to check a shell script  for  syntax  errors.   This  is
                          ignored by interactive shells.
                  -o option-name
                          The option-name can be one of the following:
                          allexport
                                  Same as -a.
                          braceexpand
                                  Same as -B.
                          emacs   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 --noediting option.  This also  affects  the
                                  editing interface used for read -e.
                          errexit Same as -e.
                          errtrace
                                  Same as -E.
                          functrace
                                  Same as -T.
                          hashall Same as -h.
                          histexpand
                                  Same as -H.
                          history Enable command history, as described above under
                                  HISTORY.  This option is on by default in inter-
                                  active shells.
                          ignoreeof
                                  The   effect   is   as   if  the  shell  command
                                  ''IGNOREEOF=10'' had been  executed  (see  Shell
                                  Variables above).
                          keyword Same as -k.
                          monitor Same as -m.
                          noclobber
                                  Same as -C.
                          noexec  Same as -n.
                          noglob  Same as -f.
                          nolog   Currently ignored.
                          notify  Same as -b.
                          nounset Same as -u.
                          onecmd  Same as -t.
                          physical
                                  Same as -P.
                          pipefail
                          xtrace  Same as -x.
                          If -o is supplied with no option-name, the values of the
                          current options are printed.  If +o is supplied with  no
                          option-name,  a  series  of set commands to recreate the
                          current option settings is  displayed  on  the  standard
                          output.
                  -p      Turn  on  privileged  mode.   In this mode, the $ENV and
                          $BASH_ENV files are not processed, shell  functions  are
                          not  inherited  from the environment, and the SHELLOPTS,
                          BASHOPTS, CDPATH,  and  GLOBIGNORE  variables,  if  they
                          appear in the environment, are ignored.  If the shell is
                          started with the effective user (group) id not equal  to
                          the  real user (group) id, and the -p option is not sup-
                          plied, these actions are taken and the effective user id
                          is  set  to  the real user id.  If the -p 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.
                  -t      Exit after reading and executing one command.
                  -u      Treat unset variables and parameters other than the spe-
                          cial  parameters "@" and "*" as an error when performing
                          parameter expansion.  If expansion is  attempted  on  an
                          unset  variable  or parameter, the shell prints an error
                          message, and, if not interactive, exits with a  non-zero
                          status.
                  -v      Print shell input lines as they are read.
                  -x      After  expanding  each simple command, for command, case
                          command, select command, or arithmetic for command, dis-
                          play  the expanded value of PS4, followed by the command
                          and its expanded arguments or associated word list.
                  -B      The shell performs brace expansion (see Brace  Expansion
                          above).  This is on by default.
                  -C      If  set,  bash  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 >.
                  -E      If set, any trap on ERR is inherited by shell functions,
                          command  substitutions,  and commands executed in a sub-
                          shell environment.  The ERR trap is normally not  inher-
                          ited in such cases.
                  -H      Enable !  style history substitution.  This option is on
                          by default when the shell is interactive.
                  -P      If set, the shell does not follow  symbolic  links  when
                          executing  commands  such  as cd that change the current
                          working  directory.   It  uses  the  physical  directory
                          structure instead.  By default, bash follows the logical
                          chain of  directories  when  performing  commands  which
                          change the current directory.
                  -T      If  set,  any traps on DEBUG and RETURN are inherited by
                          shell functions,  command  substitutions,  and  commands
                          executed  in  a  subshell  environment.   The  DEBUG and
                          RETURN traps are normally not inherited in such cases.
    
                  tered.
    
           shift [n]
                  The  positional  parameters  from n+1 ... are renamed to $1 ....
                  Parameters represented by the numbers  $#  down  to  $#-n+1  are
                  unset.   n  must  be a non-negative number less than or equal to
                  $#.  If n is 0, no parameters are changed.  If n is  not  given,
                  it  is assumed to be 1.  If n is greater than $#, the positional
                  parameters are not changed.  The return status is  greater  than
                  zero if n is greater than $# or less than zero; otherwise 0.
    
           shopt [-pqsu] [-o] [optname ...]
                  Toggle the values of variables controlling optional shell behav-
                  ior.  With no options, or with the -p option, a list of all set-
                  table options is displayed, with an indication of whether or not
                  each is set.  The -p option causes output to be displayed  in  a
                  form  that  may be reused as input.  Other options have the fol-
                  lowing meanings:
                  -s     Enable (set) each optname.
                  -u     Disable (unset) each optname.
                  -q     Suppresses normal output (quiet mode); the return  status
                         indicates whether the optname is set or unset.  If multi-
                         ple optname arguments are given with -q, the return  sta-
                         tus  is zero if all optnames are enabled; non-zero other-
                         wise.
                  -o     Restricts the values of optname to be those  defined  for
                         the -o option to the set builtin.
    
                  If  either  -s or -u is used with no optname arguments, the dis-
                  play is limited to those options which are set or unset, respec-
                  tively.   Unless otherwise noted, the shopt options are disabled
                  (unset) by default.
    
                  The return status when listing options is zero if  all  optnames
                  are  enabled,  non-zero  otherwise.   When  setting or unsetting
                  options, the return status is zero unless an optname  is  not  a
                  valid shell option.
    
                  The list of shopt options is:
    
                  autocd  If  set,  a command name that is the name of a directory
                          is executed as if it were the argument to  the  cd  com-
                          mand.  This option is only used by interactive shells.
                  cdable_vars
                          If  set,  an  argument to the cd builtin command that is
                          not a directory is assumed to be the name of a  variable
                          whose value is the directory to change to.
                  cdspell If set, minor errors in the spelling of a directory com-
                          ponent in a cd command will be  corrected.   The  errors
                          checked for are transposed characters, a missing charac-
                          ter, and one character too many.   If  a  correction  is
                          found,  the corrected file name is printed, and the com-
    
                  checkwinsize
                          If  set,  bash checks the window size after each command
                          and, if necessary,  updates  the  values  of  LINES  and
                          COLUMNS.
                  cmdhist If  set,  bash attempts to save all lines of a multiple-
                          line command in the same  history  entry.   This  allows
                          easy re-editing of multi-line commands.
                  compat31
                          If set, bash changes its behavior to that of version 3.1
                          with respect to quoted arguments to the conditional com-
                          mand's =~ operator.
                  compat32
                          If set, bash changes its behavior to that of version 3.2
                          with respect to locale-specific string  comparison  when
                          using the conditional command's < and > operators.
                  compat40
                          If set, bash changes its behavior to that of version 4.0
                          with respect to locale-specific string  comparison  when
                          using  the  conditional  command's < and > operators and
                          the effect of interrupting a command list.
                  dirspell
                          If set, bash attempts spelling correction  on  directory
                          names  during word completion if the directory name ini-
                          tially supplied does not exist.
                  dotglob If set, bash includes filenames beginning with a '.'  in
                          the results of pathname expansion.
                  execfail
                          If set, a non-interactive shell will not exit if it can-
                          not execute the file specified as  an  argument  to  the
                          exec  builtin  command.   An  interactive shell does not
                          exit if exec fails.
                  expand_aliases
                          If set, aliases are expanded as  described  above  under
                          ALIASES.  This option is enabled by default for interac-
                          tive shells.
                  extdebug
                          If set,  behavior  intended  for  use  by  debuggers  is
                          enabled:
                          1.     The -F option to the declare builtin displays the
                                 source file name and line number corresponding to
                                 each function name supplied as an argument.
                          2.     If  the  command  run by the DEBUG trap returns a
                                 non-zero value, the next command is  skipped  and
                                 not executed.
                          3.     If  the  command  run by the DEBUG 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 source  builtins),  a  call  to
                                 return is simulated.
                          4.     BASH_ARGC  and BASH_ARGV are updated as described
                                 in their descriptions above.
                          5.     Function tracing is enabled:   command  substitu-
    
                  force_fignore
                          If set, the suffixes  specified  by  the  FIGNORE  shell
                          variable  cause words to be ignored when performing word
                          completion even if the ignored words are the only possi-
                          ble  completions.   See  SHELL  VARIABLES  above  for  a
                          description of  FIGNORE.   This  option  is  enabled  by
                          default.
                  globstar
                          If set, the pattern ** used in a pathname expansion con-
                          text will match a files and zero or more directories and
                          subdirectories.  If the pattern is followed by a /, only
                          directories and subdirectories match.
                  gnu_errfmt
                          If set, shell error messages are written in the standard
                          GNU error message format.
                  histappend
                          If  set,  the history list is appended to the file named
                          by the value of the HISTFILE  variable  when  the  shell
                          exits, rather than overwriting the file.
                  histreedit
                          If  set, and readline is being used, a user is given the
                          opportunity to re-edit a failed history substitution.
                  histverify
                          If set, and readline 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 readline editing buffer, allowing further modi-
                          fication.
                  hostcomplete
                          If set, and readline is being used, bash will attempt to
                          perform  hostname  completion when a word containing a @
                          is  being  completed  (see  Completing  under   READLINE
                          above).  This is enabled by default.
                  huponexit
                          If set, bash will send SIGHUP to all jobs when an inter-
                          active login shell exits.
                  interactive_comments
                          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  COMMENTS  above).   This
                          option is enabled by default.
                  lithist If  set,  and  the cmdhist option is enabled, multi-line
                          commands are saved to the history with embedded newlines
                          rather than using semicolon separators where possible.
                  login_shell
                          The  shell  sets this option if it is started as a login
                          shell (see INVOCATION above).   The  value  may  not  be
                          changed.
                  mailwarn
                          If  set,  and  a file that bash is checking for mail has
                          been accessed since the last time it  was  checked,  the
                          message  ''The  mail in mailfile has been read'' is dis-
                          If set, bash allows patterns which match no  files  (see
                          Pathname  Expansion  above)  to expand to a null string,
                          rather than themselves.
                  progcomp
                          If set, the programmable completion facilities (see Pro-
                          grammable Completion above) are enabled.  This option is
                          enabled by default.
                  promptvars
                          If set, prompt strings undergo parameter expansion, com-
                          mand   substitution,  arithmetic  expansion,  and  quote
                          removal after being expanded as described  in  PROMPTING
                          above.  This option is enabled by default.
                  restricted_shell
                          The   shell  sets  this  option  if  it  is  started  in
                          restricted mode (see RESTRICTED SHELL below).  The value
                          may  not be changed.  This is not reset when the startup
                          files are executed, allowing the startup files  to  dis-
                          cover whether or not a shell is restricted.
                  shift_verbose
                          If  set,  the shift builtin prints an error message when
                          the shift count exceeds the number of positional parame-
                          ters.
                  sourcepath
                          If set, the source (.) builtin uses the value of PATH to
                          find the directory containing the file  supplied  as  an
                          argument.  This option is enabled by default.
                  xpg_echo
                          If   set,  the  echo  builtin  expands  backslash-escape
                          sequences by default.
           suspend [-f]
                  Suspend the execution of this shell until it receives a  SIGCONT
                  signal. When the suspended shell is a background process, it can
                  be restarted by the fg command. For more information,  read  the
                  JOB  CONTROL  section.  The  suspend command can not suspend the
                  login shell. However, when -f option is specified, suspend  com-
                  mand  can  suspend  even  login  shell.   The return status is 0
                  unless the shell is a login shell and -f is not supplied, or  if
                  job control is not enabled.
           test expr
           [ expr ]
                  Return  a  status  of  0 or 1 depending on the evaluation of the
                  conditional expression expr.  Each operator and operand must  be
                  a  separate argument.  Expressions are composed of the primaries
                  described above under CONDITIONAL EXPRESSIONS.   test  does  not
                  accept any options, nor does it accept and ignore an argument of
                  -- as signifying the end of options.
    
                  Expressions may  be  combined  using  the  following  operators,
                  listed  in  decreasing  order  of  precedence.   The  evaluation
                  depends on the number of arguments; see below.
                  ! expr True if expr is false.
                  ( expr )
                         null.
                  2 arguments
                         If the first argument is !, the expression is true if and
                         only if the second argument is null.  If the first  argu-
                         ment  is  one  of  the unary conditional operators listed
                         above under CONDITIONAL EXPRESSIONS,  the  expression  is
                         true if the unary test is true.  If the first argument is
                         not a valid unary conditional operator, the expression is
                         false.
                  3 arguments
                         If  the  second argument is one of the binary conditional
                         operators listed above under CONDITIONAL EXPRESSIONS, the
                         result of the expression is the result of the binary test
                         using the first and third arguments as operands.  The  -a
                         and  -o  operators  are  considered binary operators when
                         there are three arguments.  If the first argument  is  !,
                         the  value is the negation of the two-argument test using
                         the second and third arguments.  If the first argument is
                         exactly ( and the third argument is exactly ), the result
                         is the one-argument test of the second argument.   Other-
                         wise, the expression is false.
                  4 arguments
                         If the first argument is !, the result is the negation of
                         the three-argument expression composed of  the  remaining
                         arguments.  Otherwise, the expression is parsed and eval-
                         uated according to  precedence  using  the  rules  listed
                         above.
                  5 or more arguments
                         The  expression  is  parsed  and  evaluated  according to
                         precedence using the rules listed above.
    
           times  Print the accumulated user and system times for  the  shell  and
                  for processes run from the shell.  The return status is 0.
    
           trap [-lp] [[arg] sigspec ...]
                  The  command  arg  is  to  be  read  and executed when the shell
                  receives signal(s) sigspec.  If arg is absent (and  there  is  a
                  single  sigspec)  or  -,  each  specified signal is reset to its
                  original disposition (the value it  had  upon  entrance  to  the
                  shell).   If arg is the null string the signal specified by each
                  sigspec is ignored by the shell and by the commands it  invokes.
                  If  arg  is  not present and -p has been supplied, then the trap
                  commands associated with each  sigspec  are  displayed.   If  no
                  arguments  are  supplied or if only -p is given, trap prints the
                  list of commands associated with each  signal.   The  -l  option
                  causes  the shell to print a list of signal names and their cor-
                  responding numbers.   Each  sigspec  is  either  a  signal  name
                  defined  in  <signal.h>,  or  a signal number.  Signal names are
                  case insensitive and the SIG prefix is optional.
    
                  If a sigspec is EXIT (0) the command arg  is  executed  on  exit
                  from  the shell.  If a sigspec is DEBUG, the command arg is exe-
                  command executed in a && or || list, or if the command's  return
                  value  is  being  inverted via !.  These are the same conditions
                  obeyed by the errexit option.
    
                  Signals ignored upon entry to the shell cannot be trapped, reset
                  or listed.  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 sigspec
                  is invalid; otherwise trap returns true.
    
           type [-aftpP] name [name ...]
                  With no options, indicate how each name would be interpreted  if
                  used as a command name.  If the -t option is used, type prints a
                  string which is one of alias,  keyword,  function,  builtin,  or
                  file  if  name  is  an  alias,  shell  reserved  word, function,
                  builtin, or disk file, respectively.  If the name is not  found,
                  then  nothing  is  printed,  and  an  exit  status  of  false is
                  returned.  If the -p option is used,  type  either  returns  the
                  name of the disk file that would be executed if name were speci-
                  fied as a command name, or nothing if ''type -t name'' would not
                  return  file.  The -P option forces a PATH search for each name,
                  even if ''type -t name'' would not return file.  If a command is
                  hashed,  -p  and  -P print the hashed value, not necessarily the
                  file that appears first in PATH.  If the -a option is used, type
                  prints  all of the places that contain an executable named name.
                  This includes aliases and functions,  if  and  only  if  the  -p
                  option  is  not  also used.  The table of hashed commands is not
                  consulted when using -a.  The -f option suppresses  shell  func-
                  tion  lookup, as with the command builtin.  type returns true if
                  all of the arguments are found, false if any are not found.
    
           ulimit [-HSTabcdefilmnpqrstuvx [limit]]
                  Provides control over the resources available to the  shell  and
                  to  processes started by it, on systems that allow such control.
                  The -H and -S 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 -H nor -S is speci-
                  fied, both the soft and hard limits are set.  The value of limit
                  can be a number in the unit specified for the resource or one of
                  the special values hard, soft, or unlimited, which stand for the
                  current  hard  limit,  the  current  soft  limit,  and no limit,
                  respectively.  If limit is omitted, the  current  value  of  the
                  soft  limit  of the resource is printed, unless the -H option is
                  given.  When more than one resource is specified, the limit name
                  and unit are printed before the value.  Other options are inter-
                  preted as follows:
                  -a     All current limits are reported
                  -b     The maximum socket buffer size
                  -c     The maximum size of core files created
                  -d     The maximum size of a process's data segment
                  -e     The maximum scheduling priority ("nice")
                         user
                  -v     The maximum amount of virtual  memory  available  to  the
                         shell
                  -x     The maximum number of file locks
                  -T     The maximum number of threads
    
                  If limit is given, it is the new value of the specified resource
                  (the -a option is display only).  If no option is given, then -f
                  is  assumed.  Values are in 1024-byte increments, except for -t,
                  which is in seconds, -p, which is in units of  512-byte  blocks,
                  and  -T,  -b, -n, and -u, which are unscaled values.  The return
                  status is 0 unless an invalid option or argument is supplied, or
                  an  error  occurs  while  setting  a  new  limit.  In POSIX Mode
                  512-byte blocks are used for the '-c' and '-f' options.
    
           umask [-p] [-S] [mode]
                  The user file-creation mask is set to mode.  If mode 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
                  chmod(1).   If mode is omitted, the current value of the mask is
                  printed.  The -S option causes the mask to be  printed  in  sym-
                  bolic  form;  the  default output is an octal number.  If the -p
                  option is supplied, and mode 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 mode  argument  was  supplied,
                  and false otherwise.
    
           unalias [-a] [name ...]
                  Remove  each  name  from  the list of defined aliases.  If -a is
                  supplied, all alias definitions are removed.  The  return  value
                  is true unless a supplied name is not a defined alias.
    
           unset [-fv] [name ...]
                  For  each  name,  remove the corresponding variable or function.
                  If no options are supplied, or the -v option is given, each name
                  refers  to  a  shell  variable.   Read-only variables may not be
                  unset.  If -f is specified, each name refers to  a  shell  func-
                  tion,  and the function definition is removed.  Each unset vari-
                  able or function is removed from the environment passed to  sub-
                  sequent  commands.   If any of COMP_WORDBREAKS, RANDOM, SECONDS,
                  LINENO, HISTCMD, FUNCNAME, GROUPS, or DIRSTACK are  unset,  they
                  lose  their  special  properties,  even if they are subsequently
                  reset.  The exit status is true unless a name is readonly.
    
           wait [n ...]
                  Wait for each specified process and return its termination  sta-
                  tus.   Each  n  may be a process ID or a job specification; if a
                  job spec is given, all processes  in  that  job's  pipeline  are
                  waited  for.  If n is not given, all currently active child pro-
                  cesses are waited for, and the return  status  is  zero.   If  n
                  specifies  a  non-existent  process or job, the return status is
                  127.  Otherwise, the return status is the  exit  status  of  the
    
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