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名前

       bash,  :, ., [, alias, bg, bind, break, builtin, cd, command, compgen, complete, continue,
       declare, dirs, disown, echo, enable, eval, exec, exit,  export,  fc,  fg,  getopts,  hash,
       help,  history,  jobs, kill, let, local, logout, popd, printf, pushd, pwd, read, readonly,
       return, set, shift, shopt, source, suspend, test,  times,  trap,  type,  typeset,  ulimit,
       umask, unalias, unset, wait - bash の組み込みコマンド。bash(1) を参照すること。

bash の組み込みコマンド

       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  -
       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 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 executed from filename.  If filename does not
              contain a slash, filenames in PATH  are  used  to  find  the  directory  containing
              filename.   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  positional  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 supplied, 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  run when job control is disabled or, when run with job
              control enabled, any specified jobspec was not found or  was  started  without  job
              control.

       bind [-m keymap] [-lpsvPSVX]
       bind [-m keymap] [-q function] [-u function] [-r keyseq]
       bind [-m keymap] -f filename
       bind [-m keymap] -x keyseq:shell-command
       bind [-m keymap] keyseq:function-name
       bind readline-command
              Display  current  readline  key  and  function  bindings,  bind a key sequence to a
              readline function or macro, or set a readline variable.  Each  non-option  argument
              is  a  command  as it would appear in .inputrc, but each binding or command must be
              passed as a separate argument; e.g., '"\C-x\C-r": re-read-init-file'.  Options,  if
              supplied, have the following meanings:
              -m keymap
                     Use  keymap  as  the  keymap  to  be  affected  by  the subsequent bindings.
                     Acceptable keymap names are emacs, emacs-standard,  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 readline 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  READLINE_POINT,  those new values will be
                     reflected in the editing state.
              -X     List all key sequences bound to shell commands and the  associated  commands
                     in a format that can be reused as input.

              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 0 unless n is not greater than or
              equal to 1.

       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 functionality of the builtin within the  function.   The  cd
              builtin   is   commonly  redefined  this  way.   The  return  status  is  false  if
              shell-builtin is not a shell builtin command.

       caller [expr]
              Returns the context of any active subroutine call (a shell  function  or  a  script
              executed  with  the  . or source builtins).  Without expr, caller displays the line
              number and source filename of the  current  subroutine  call.   If  a  non-negative
              integer  is supplied as expr, caller 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  subroutine  call  or  expr  does  not correspond to a valid position in the call
              stack.

       cd [-L|[-P [-e]] [-@]] [dir]
              Change the current directory to dir.  if dir is not supplied, the value of the HOME
              shell variable is the default.  Any additional arguments following dir are ignored.
              The variable CDPATH defines the search path for the directory containing dir:  each
              directory  name  in  CDPATH  is  searched  for 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 causes cd to use the  physical  directory  structure  by
              resolving symbolic links while traversing dir and before processing instances of ..
              in dir (see also the -P option to the set builtin command); the  -L  option  forces
              symbolic  links  to be followed by resolving the link after processing instances of
              .. in dir.  If .. appears in dir, it  is  processed  by  removing  the  immediately
              previous  pathname component from dir, back to a slash or the beginning of dir.  If
              the -e option is supplied with -P, and the  current  working  directory  cannot  be
              successfully  determined  after  a  successful  directory change, cd 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 $OLDPWD before the directory change  is  attempted.   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
              successfully 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 filename 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 cannot be found, the exit status is  127.
              Otherwise, the exit status 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 programmable completion
              code had generated them directly from a  completion  specification  with  the  same
              flags.   If  word  is  specified,  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 globpat] [-W wordlist] [-F
       function] [-C command]
              [-X filterpat] [-P prefix] [-S suffix] name [name ...]
       complete -pr [-DE] [name ...]
              Specify how arguments to each name should  be  completed.   If  the  -p  option  is
              supplied,  or  if  no  options are supplied, existing completion specifications are
              printed in a way that allows them to be reused as input.  The -r option  removes  a
              completion  specification  for  each  name,  or,  if  no  names  are  supplied, all
              completion specifications.  The -D option indicates that the remaining options  and
              actions  should  apply  to  the ``default'' command completion; that is, completion
              attempted on a command for which no completion has previously been defined.  The -E
              option  indicates  that the remaining options and actions should apply to ``empty''
              command completion; that is, completion attempted on a blank line.

              The process of applying these completion specifications  when  word  completion  is
              attempted is described above under Programmable 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 expansion before the complete builtin is invoked.
              -o comp-option
                      The  comp-option controls several aspects of the compspec's behavior beyond
                      the simple generation of completions.  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  compspec  generates  no
                              matches.
                      filenames
                              Tell  readline  that  the  compspec  generates filenames, so it can
                              perform any filename-specific processing (like adding  a  slash  to
                              directory   names,   quoting  special  characters,  or  suppressing
                              trailing spaces).  Intended to be used with shell functions.
                      noquote Tell readline  not  to  quote  the  completed  words  if  they  are
                              filenames (quoting filenames is the default).
                      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.
                      export  Names of exported shell variables.  May also be specified as -e.
                      file    File names.  May also be specified as -f.
                      function
                              Names of shell functions.
                      group   Group names.  May also be specified as -g.
                      helptopic
                              Help topics as accepted by the help builtin.
                      hostname
                              Hostnames,  as  taken from the file specified by the HOSTFILE shell
                              variable.
                      job     Job names, if job control is active.  May also be specified as -j.
                      keyword Shell reserved words.  May also be specified as -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 specified as -v.
              -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 the function is executed, the first argument ($1) is the name  of  the
                      command  whose  arguments  are being completed, the second argument ($2) is
                      the word being completed, and the third argument ($3) is the word preceding
                      the  word  being  completed on the current command line.  When it finishes,
                      the possible completions are retrieved from  the  value  of  the  COMPREPLY
                      array variable.
              -G globpat
                      The pathname expansion pattern globpat is expanded to generate the possible
                      completions.
              -P prefix
                      prefix is added at the beginning of  each  possible  completion  after  all
                      other options have been applied.
              -S suffix
                      suffix is appended to each possible completion after all other options have
                      been applied.
              -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 completed.
              -X filterpat
                      filterpat is a pattern as used for pathname expansion.  It  is  applied  to
                      the  list  of  possible  completions generated 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.

              The return value is true unless an invalid option is supplied, an option other than
              -p  or  -r  is  supplied  without  a  name argument, 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 options, or for the
              currently-executing completion if no names are supplied.  If no options are  given,
              display  the  completion  options  for  each  name  or the current completion.  The
              possible values of option are those valid for the complete builtin described above.
              The  -D option indicates that the remaining options should apply to the ``default''
              command completion; that is,  completion  attempted  on  a  command  for  which  no
              completion has previously been defined.  The -E option indicates that the remaining
              options should apply to ``empty'' command completion; that is, completion attempted
              on a blank line.

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

       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.  The return value is 0 unless n is not greater than or  equal  to
              1.

       declare [-aAfFgilnrtux] [-p] [name[=value] ...]
       typeset [-aAfFgilnrtux] [-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, other than -f
              and -F, 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
              definitions;  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  displayed  as  well.  The -F option implies -f.  The -g
              option forces variables to be created or modified at the global  scope,  even  when
              declare  is  executed  in a shell function.  It is ignored in all other cases.  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 evaluation (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.
              -n     Give  each name the nameref attribute, making it a name reference to another
                     variable.  That other variable  is  defined  by  the  value  of  name.   All
                     references  and  assignments  to  name, except for changing the -n attribute
                     itself, are performed on the variable referenced by name's  value.   The  -n
                     attribute cannot be applied to array variables.
              -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.

              Using  `+' instead of `-' turns off the attribute instead, with the exceptions that
              +a may not be used to destroy an array variable and +r will not remove the readonly
              attribute.   When  used in a function, declare and typeset make each name local, as
              with the local command, unless the -g option is supplied.  If a  variable  name  is
              followed by =value, the value of the variable is set to value.  When using -a or -A
              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  ``-f
              foo=bar'',  an attempt is made to assign a value to a readonly variable, an attempt
              is made to assign  a  value  to  an  array  variable  without  using  the  compound
              assignment  syntax  (see  Arrays  above),  one  of  the  names is not a valid shell
              variable name, an attempt is made to  turn  off  readonly  status  for  a  readonly
              variable,  an attempt is made to turn off array status for an array variable, or an
              attempt is made to display a non-existent function with -f.

       dirs [-clpv] [+n] [-n]
              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.
              -c     Clears the directory stack by deleting all of the entries.
              -l     Produces  a  listing using full pathnames; 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, prefixing each entry with
                     its index in the stack.
              +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.

              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, remove each jobspec from the table of active jobs.  If jobspec  is
              not  present,  and neither the -a nor the -r option is supplied, the current job is
              used.  If the -h option is given, each jobspec is not removed from the  table,  but
              is marked so that SIGHUP is not sent to the job if the shell receives a SIGHUP.  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 jobspec does not specify a valid job.

       echo [-neE] [arg ...]
              Output the args, separated by spaces, followed by a newline.  The return status  is
              0  unless  a  write  error  occurs.   If  -n  is specified, the trailing newline is
              suppressed.  If the -e option is given, interpretation of the following  backslash-
              escaped  characters is enabled.  The -E option disables the interpretation of these
              escape characters, 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
              \e
              \E     an escape character
              \f     form feed
              \n     new line
              \r     carriage return
              \t     horizontal tab
              \v     vertical tab
              \\     backslash
              \0nnn  the  eight-bit  character  whose value is the octal value nnn (zero to three
                     octal digits)
              \xHH   the eight-bit character whose value is the hexadecimal value HH (one or  two
                     hex digits)
              \uHHHH the  Unicode  (ISO/IEC 10646) character whose value is the hexadecimal value
                     HHHH (one to four hex digits)
              \UHHHHHHHH
                     the Unicode (ISO/IEC 10646) character whose value is the  hexadecimal  value
                     HHHHHHHH (one to eight hex digits)

       enable [-a] [-dnps] [-f filename] [name ...]
              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 -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 arguments, the list consists of all enabled shell
              builtins.   If  -n  is  supplied,  only  disabled  builtins  are printed.  If -a is
              supplied, the list printed includes all builtins, with an indication 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 command.  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 beginning 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 cannot  be  executed  for  some  reason,  a  non-
              interactive  shell  exits,  unless  the  execfail shell option is enabled.  In that
              case, it returns failure.  An interactive shell returns failure if the file  cannot
              be  executed.   If  command  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.

       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  environment  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 names
              of all exported variables is printed.  The -n option causes the export property  to
              be  removed  from each name.  If a variable name is followed by =word, the value of
              the variable is set to word.  export returns an exit status of 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.

       fc [-e ename] [-lnr] [first] [last]
       fc -s [pat=rep] [cmd]
              The first form selects a range of commands from first to last from the history list
              and  displays  or edits and re-executes them.  First and last 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).  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 specified 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.   Otherwise,  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,
              vi 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.  Command is intepreted the same as first above.  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 command.

              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-executed, 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 specify 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  parameters.   optstring
              contains  the  option  characters to be recognized; if a character is followed by a
              colon, the option is expected to have an argument, which should be  separated  from
              it  by  white  space.   The  colon  and question mark characters may not be used as
              option characters.  Each time it is invoked, 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 automatically; it must be manually reset between multiple calls to
              getopts within the same shell invocation if a new set of parameters is to be used.

              When the end of options is encountered, getopts exits with a return  value  greater
              than  zero.   OPTIND is set to the index of the first non-option argument, and name
              is set to ?.

              getopts normally parses the positional parameters, but if more arguments are  given
              in args, getopts parses those instead.

              getopts  can  report  errors in two ways.  If the first character of optstring is a
              colon, silent error reporting is used.  In normal  operation,  diagnostic  messages
              are  printed  when invalid options or missing option arguments are encountered.  If
              the variable OPTERR is set to 0, no error messages will be displayed, 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]
              Each  time  hash is invoked, the full pathname of the command name is determined by
              searching the directories  in  $PATH  and  remembered.   Any  previously-remembered
              pathname  is discarded.  If the -p option is supplied, no path search is performed,
              and filename is used as the full filename 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 format 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 ...]
              With no options, display the command history list with line numbers.  Lines  listed
              with a * have been modified.  An argument of n lists only the last n lines.  If the
              shell variable HISTTIMEFORMAT is set and not null, it is used as  a  format  string
              for  strftime(3)  to  display the time stamp associated with each displayed history
              entry.  No intervening blank is printed between the formatted time  stamp  and  the
              history line.  If filename is supplied, it is used as the name of the history file;
              if not, the value of HISTFILE is used.  Options, if supplied,  have  the  following
              meanings:
              -c     Clear the history list by deleting all the entries.
              -d offset
                     Delete the history entry at position offset.
              -a     Append  the ``new'' history lines (history lines entered 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 append them to the current history
                     list.
              -w     Write  the current history list to the history file, overwriting 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 information associated with
              each history entry is written to the history file, marked with the history  comment
              character.  When the history file is read, lines beginning with the history comment
              character followed immediately by a digit are interpreted  as  timestamps  for  the
              previous  history  line.   The  return  value  is  0  unless  an  invalid option is
              encountered, an error occurs while reading or writing the history file, an  invalid
              offset  is  supplied  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 following meanings:
              -l     List process IDs in addition to the normal information.
              -n     Display information only about jobs that have changed status since the  user
                     was last notified of their status.
              -p     List only the process ID of the job's process group leader.
              -r     Display only running jobs.
              -s     Display only 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 named by pid or
              jobspec.  sigspec is either a case-insensitive signal name such as SIGKILL (with or
              without  the SIG prefix) or a signal number; signum is a signal number.  If sigspec
              is not present, then SIGTERM is assumed.  An argument of -l lists the signal names.
              If  any  arguments  are  supplied  when  -l  is  given,  the  names  of the signals
              corresponding to the arguments are  listed,  and  the  return  status  is  0.   The
              exit_status  argument  to  -l  is a number specifying either a signal number or the
              exit status of a process terminated by a signal.  kill returns true if at least one
              signal  was  successfully sent, or false if an error occurs or an invalid option is
              encountered.

       let arg [arg ...]
              Each arg is an arithmetic expression to be  evaluated  (see  ARITHMETIC  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
              function 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 variable array,  or  from
              file  descriptor  fd  if  the  -u  option is supplied.  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 standard 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  and
              the  line  to  be  assigned  to  that element as additional arguments.  callback 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,  removes  the  top
              directory  from  the stack, and performs a cd to the new top directory.  Arguments,
              if supplied, have the following meanings:
              -n     Suppresses the normal change of directory when removing directories from the
                     stack, so that only the stack is manipulated.
              +n     Removes  the  nth  entry  counting  from the left of the list shown by dirs,
                     starting with zero.  For example: ``popd +0'' removes the  first  directory,
                     ``popd +1'' the second.
              -n     Removes  the  nth  entry  counting from the right of the list shown by dirs,
                     starting with zero.  For example: ``popd -0'' removes  the  last  directory,
                     ``popd -1'' the next to last.

              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-existent 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 -v option causes the output to be assigned to the variable var rather
              than being printed to the standard output.

              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  format  specifications,
              each  of which causes printing of the next successive argument.  In addition to the
              standard  printf(1)  format  specifications,  printf   interprets   the   following
              extensions:
              %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).
              %q     causes printf to output the corresponding argument in a format that  can  be
                     reused as shell input.
              %(datefmt)T
                     causes printf to output the date-time string resulting from using datefmt as
                     a format string for strftime(3).  The corresponding argument 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 argument is specified, conversion behaves
                     as if -1 had been given.  This is an exception to the usual printf behavior.

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

              The format is reused as necessary to consume all of the arguments.  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 as if it had been supplied  as  the  argument  to  the  cd
                     builtin.

              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  directory  stack  is empty, a non-existent directory stack
              element is specified,  or  the  directory  change  to  the  specified  new  current
              directory fails.

       pwd [-LP]
              Print the absolute pathname of the current working directory.  The pathname printed
              contains no symbolic links if the -P option is supplied or the -o  physical  option
              to  the  set  builtin  command  is enabled.  If the -L option is used, the pathname
              printed may contain symbolic links.  The return status is 0 unless an error  occurs
              while reading the name of the current directory or an invalid option is supplied.

       read  [-ers]  [-a  aname]  [-d  delim]  [-i  text] [-n nchars] [-N nchars] [-p 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
              intervening  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 using the same rules
              the shell uses for expansion (described above under Word Splitting).  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 following 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.  Readline 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  delimiter  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 characters 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  newline, 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 backslash is considered
                     to be part of the line.  In particular, a backslash-newline pair may not  be
                     used as a line continuation.
              -s     Silent mode.  If input is coming from a terminal, characters are not echoed.
              -t timeout
                     Cause  read to time out and return failure if a complete line of input (or a
                     specified number of characters) is not read within timeout seconds.  timeout
                     may  be  a  decimal  number  with a fractional portion following the decimal
                     point.  This option is only effective  if  read  is  reading  input  from  a
                     terminal,  pipe,  or  other special file; it has no effect when reading from
                     regular files.  If read times out, read saves any partial  input  read  into
                     the  specified  variable  name.   If timeout is 0, read returns immediately,
                     without trying to read any data.  The exit status is 0 if input is available
                     on  the  specified  file descriptor, non-zero otherwise.  The exit status is
                     greater than 128 if the timeout is exceeded.
              -u fd  Read input from file descriptor fd.

              If no names are supplied, the line read is assigned to  the  variable  REPLY.   The
              return  code  is  zero, unless end-of-file is encountered, read times out (in which
              case the return code is greater than 128), a variable  assignment  error  (such  as
              assigning to a readonly variable) occurs, or an invalid file descriptor is supplied
              as the argument to -u.

       readonly [-aAf] [-p] [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
              both options are supplied, -A takes precedence.  If no name arguments are given, or
              if  the  -p 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 -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  stop  executing and return the value specified by n to its
              caller.  If n is omitted, the return status is that of the last command executed in
              the function body.  If return is 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 n is supplied, the return value is
              its  least significant 8 bits.  The return status is non-zero if return is supplied
              a non-numeric argument, or is used outside a function and not during execution of a
              script  by  .  or  source.  Any command associated with the RETURN trap is executed
              before execution resumes after the function or script.

       set [--abefhkmnptuvxBCEHPT] [-o option-name] [arg ...]
       set [+abefhkmnptuvxBCEHPT] [+o option-name] [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  cannot  be  reset.   In  posix  mode,  only  shell
              variables  are listed.  The output is sorted according to the current locale.  When
              options are specified, they set or unset shell attributes.  Any arguments remaining
              after option processing are treated as values 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  immediately,  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  list, or a compound command (see SHELL GRAMMAR above),  exits
                      with a non-zero status.  The shell does not exit if the command that  fails
                      is part of the command list immediately following a while or until keyword,
                      part of the test following the if or  elif  reserved  words,  part  of  any
                      command  executed in a && or || list except the command following the final
                      && or ||, any command in a pipeline but  the  last,  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  -e  was
                      being ignored, the shell does not exit.  A trap on ERR, if set, is executed
                      before the shell exits.  This option applies to the shell  environment  and
                      each  subshell  environment  separately  (see COMMAND EXECUTION ENVIRONMENT
                      above), and may cause subshells to exit before executing all  the  commands
                      in the subshell.

                      If  a  compound command or shell function executes in a context where -e is
                      being ignored, none of the commands executed within the compound command or
                      function  body  will be affected by the -e setting, even if -e is set and a
                      command returns a failure status.  If a compound command or shell  function
                      sets -e while executing in a context where -e is ignored, that setting will
                      not have any effect until the compound command or  the  command  containing
                      the function call completes.
              -f      Disable pathname expansion.
              -h      Remember  the  location  of  commands  as they are looked up 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).  All
                      processes  run  in  a  separate  process  group.   When  a  background  job
                      completes, the shell prints a line containing its exit status.
              -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 interface.  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 interactive 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
                              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.
                      posix   Change  the  behavior  of  bash where the default operation differs
                              from the POSIX standard to match the standard  (posix  mode).   See
                              SEE ALSO below for a reference to a document that details how posix
                              mode affects bash's behavior.
                      privileged
                              Same as -p.
                      verbose Same as -v.
                      vi      Use a vi-style command line editing interface.  This  also  affects
                              the editing interface used for read -e.
                      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 supplied, these actions are taken and the effective user id
                      is set to the real user id.  If the -p option is supplied at  startup,  the
                      effective  user  id  is  not  reset.   Turning  this  option off causes the
                      effective user and group ids to be set to the real user and group ids.
              -t      Exit after reading and executing one command.
              -u      Treat unset variables and parameters other than the special 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, display  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 redirection operator >| instead of >.
              -E      If  set,  any  trap  on  ERR  is  inherited  by  shell  functions,  command
                      substitutions,  and  commands  executed in a subshell environment.  The ERR
                      trap is normally not inherited 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 resolve 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.
              --      If no arguments follow this option,  then  the  positional  parameters  are
                      unset.   Otherwise,  the positional parameters are set to the args, even if
                      some of them begin with a -.
              -       Signal the end of options, cause all remaining args to be assigned  to  the
                      positional parameters.  The -x and -v options are turned off.  If there are
                      no args, the positional parameters remain unchanged.

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

       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 settings controlling optional shell  behavior.   The  settings
              can  be  either  those  listed below, or, if the -o option is used, those available
              with the -o option to the set builtin command.  With no options,  or  with  the  -p
              option,  a list of all settable 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 following 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 multiple optname arguments are  given  with
                     -q,  the  return  status  is  zero  if  all  optnames  are enabled; non-zero
                     otherwise.
              -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, shopt shows only those
              options which are set or unset, respectively.  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  command.   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 component in a cd
                      command  will  be  corrected.   The  errors  checked  for  are   transposed
                      characters,  a  missing  character,  and  one  character  too  many.   If a
                      correction is found, the corrected filename is  printed,  and  the  command
                      proceeds.  This option is only used by interactive shells.
              checkhash
                      If  set,  bash  checks that a command found in the hash table exists before
                      trying to execute it.  If a hashed command no longer exists, a normal  path
                      search is performed.
              checkjobs
                      If  set,  bash  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 JOB CONTROL above).  The shell always postpones exiting if any
                      jobs are stopped.
              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 command's =~  operator  and  locale-
                      specific  string comparison when using the [[ conditional command's < and >
                      operators.  Bash  versions  prior  to  bash-4.1  use  ASCII  collation  and
                      strcmp(3);  bash-4.1  and later use the current locale's collation sequence
                      and strcoll(3).
              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 (see previous item).
              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  (see  description  of  compat31)  and  the   effect   of
                      interrupting  a  command  list.   Bash versions 4.0 and later interrupt the
                      list as if the shell received the  interrupt;  previous  versions  continue
                      with the next command in the list.
              compat41
                      If  set, bash, when in posix mode, treats a single quote in a double-quoted
                      parameter expansion as a special character.  The single quotes  must  match
                      (an  even  number)  and  the  characters  between  the  single  quotes  are
                      considered quoted.  This is the behavior of posix mode through version 4.1.
                      The default bash behavior remains as in previous versions.
              compat42
                      If  set,  bash  does  not  process  the  replacement  string in the pattern
                      substitution word expansion using quote removal.
              complete_fullquote
                      If set, bash quotes all shell metacharacters  in  filenames  and  directory
                      names  when performing completion.  If not set, bash removes metacharacters
                      such as the dollar 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 expand 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 backslashes to quote completed filenames.
                      This variable is set by default, which is  the  default  bash  behavior  in
                      versions through 4.2.
              direxpand
                      If  set,  bash  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, bash attempts to preserve what the
                      user typed.
              dirspell
                      If set, bash attempts spelling correction on directory  names  during  word
                      completion if the directory name initially 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 cannot 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 interactive 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  subroutine (a shell function or a shell
                             script executed 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 substitution, shell functions,
                             and  subshells invoked with ( command ) inherit the DEBUG and RETURN
                             traps.
                      6.     Error tracing is enabled:  command  substitution,  shell  functions,
                             and subshells invoked with ( command ) inherit the ERR trap.
              extglob If  set,  the  extended  pattern  matching  features  described above under
                      Pathname Expansion are enabled.
              extquote
                      If set, $'string' and $"string" quoting is  performed  within  ${parameter}
                      expansions enclosed in double quotes.  This option is enabled by default.
              failglob
                      If  set,  patterns  which fail to match filenames during pathname expansion
                      result in an expansion error.
              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 possible completions.  See SHELL VARIABLES above for a description
                      of FIGNORE.  This option is enabled by default.
              globasciiranges
                      If set, range expressions used in pattern matching bracket expressions (see
                      Pattern Matching above) 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 b will not  collate  between  A  and  B,  and
                      upper-case and lower-case ASCII characters will collate together.
              globstar
                      If  set, the pattern ** used in a pathname expansion context will match all
                      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 history substitution are
                      not immediately passed to the shell parser.  Instead, the resulting line is
                      loaded into the readline editing buffer, allowing further modification.
              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 interactive  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.
              lastpipe
                      If set, and job control is not active, the shell runs the last command of a
                      pipeline not executed in the background in the current shell environment.
              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 displayed.
              no_empty_cmd_completion
                      If  set,  and  readline  is being used, bash will not attempt to search the
                      PATH for possible completions when completion  is  attempted  on  an  empty
                      line.
              nocaseglob
                      If   set,  bash  matches  filenames  in  a  case-insensitive  fashion  when
                      performing pathname expansion (see Pathname Expansion above).
              nocasematch
                      If set, bash matches patterns in a case-insensitive fashion when performing
                      matching while executing case or [[ conditional commands.
              nullglob
                      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 Programmable Completion
                      above) are enabled.  This option is enabled by default.
              promptvars
                      If  set,  prompt strings undergo parameter expansion, command 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 discover
                      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 parameters.
              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.  A login
              shell cannot be suspended; the -f option can be used to override this and force the
              suspension.  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 (true) or  1  (false)  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.
              Operator precedence is used when there are five or more arguments.
              ! expr True if expr is false.
              ( expr )
                     Returns the value of  expr.   This  may  be  used  to  override  the  normal
                     precedence of operators.
              expr1 -a expr2
                     True if both expr1 and expr2 are true.
              expr1 -o expr2
                     True if either expr1 or expr2 is true.

              test  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 argument 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
                     The following conditions are applied in the order  listed.   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.  Otherwise, 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 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 used with test or [, the < and > operators sort lexicographically using  ASCII
              ordering.

       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 corresponding 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 executed before every simple command, for
              command, case command, select command, every arithmetic for command, and before the
              first command executes in a shell function (see SHELL GRAMMAR above).  Refer to the
              description of the extdebug option to the shopt builtin for details of  its  effect
              on the DEBUG trap.  If a sigspec is RETURN, the command arg is executed each time a
              shell function or a  script  executed  with  the  .  or  source  builtins  finishes
              executing.

              If  a  sigspec is ERR, the command arg is executed whenever a 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 ERR trap is not
              executed if the failed command is part of the command list immediately following  a
              while  or  until  keyword,  part  of the test in an if 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 errexit (-e) option.

              Signals ignored upon entry to the  shell  cannot  be  trapped  or  reset.   Trapped
              signals that are not being ignored are reset to their original values in a 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  specified  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,
              which is 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 function 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 specified, 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 interpreted 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")
              -f     The maximum size of files written by the shell and its children
              -i     The maximum number of pending signals
              -l     The maximum size that may be locked into memory
              -m     The maximum resident set size (many systems do not honor this limit)
              -n     The  maximum number of open file descriptors (most systems do not allow this
                     value to be set)
              -p     The pipe size in 512-byte blocks (this may not be set)
              -q     The maximum number of bytes in POSIX message queues
              -r     The maximum real-time scheduling priority
              -s     The maximum stack size
              -t     The maximum amount of cpu time in seconds
              -u     The maximum number of processes available to a single user
              -v     The maximum amount of virtual memory available to the  shell  and,  on  some
                     systems, to its children
              -x     The maximum number of file locks
              -T     The maximum number of threads

              If  limit  is  given,  and the -a option is not used, limit is the new value of the
              specified resource.  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.

       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 symbolic 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] [-n] [name ...]
              For  each name, remove the corresponding variable or function.  If the -v option is
              given, each name refers to a shell variable, and that variable is  removed.   Read-
              only  variables  may not be unset.  If -f is specified, each name refers to a shell
              function, and the function definition is removed.  If the -n  option  is  supplied,
              and  name  is a variable with the nameref attribute, name will be unset rather than
              the variable it references.  -n has no effect if the -f option is supplied.  If  no
              options  are  supplied,  each name refers to a variable; if there is no variable by
              that name, any function with that name is unset.  Each unset variable  or  function
              is  removed  from  the  environment  passed  to  subsequent  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] [n ...]
              Wait for each specified child process and return its termination  status.   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 processes are waited for, and the return status is zero.  If the -n option is
              supplied, wait waits for any job to terminate and returns its exit  status.   If  n
              specifies  a non-existent process or job, the return status is 127.  Otherwise, the
              return status is the exit status of the last process or job waited for.

関連項目

       bash(1), sh(1)