/usr/bin/getopt

getopt - コマンドオプションを解析する（機能強化）

SYNOPSIS

      getopt optstring parameters
      getopt [options] [--] optstring parameters
      getopt [options] -o|--options optstring [options] [--] parameters

DESCRIPTION

      getopt  is  used  to break up (parse) options in command lines for easy parsing by shell procedures,
      and to check for valid options.  It uses the GNU getopt(3) routines to do this.

      The parameters getopt is called with can be divided into two parts: options  which  modify  the  way
      getopt will do the parsing (the options and the optstring in the SYNOPSIS), and the parameters which
      are to be parsed (parameters in the SYNOPSIS).  The second part will start at the  first  non-option
      parameter  that  is  not  an  option argument, or after the first occurrence of '--'.  If no '-o' or
      '--options' option is found in the first part, the first parameter of the second part is used as the
      short options string.

      If  the  environment  variable  GETOPT_COMPATIBLE is set, or if the first parameter is not an option
      (does not start with a '-', the first format in the SYNOPSIS), getopt will generate output  that  is
      compatible  with that of other versions of getopt(1).  It will still do parameter shuffling and rec‐
      ognize optional arguments (see section COMPATIBILITY for more information).

      Traditional implementations of getopt(1) are unable to cope with whitespace  and  other  (shell-spe‐
      cific)  special  characters in arguments and non-option parameters.  To solve this problem, this im‐
      plementation can generate quoted output which must once again be interpreted by the  shell  (usually
      by  using  the eval command).  This has the effect of preserving those characters, but you must call
      getopt in a way that is no longer compatible with other versions (the second or third format in  the
      SYNOPSIS).  To determine whether this enhanced version of getopt(1) is installed, a special test op‐
      tion (-T) can be used.

OPTIONS

      -a, --alternative
             Allow long options to start with a single '-'.

      -h, --help
             Display help text and exit.  No other output is generated.

      -l, --longoptions longopts
             The long (multi-character) options to be recognized.  More than one option name may be speci‐
             fied  at once, by separating the names with commas.  This option may be given more than once,
             the longopts are cumulative.  Each long option name in longopts may be followed by one  colon
             to  indicate it has a required argument, and by two colons to indicate it has an optional ar‐
             gument.

      -n, --name progname
             The name that will be used by the getopt(3) routines when it reports errors.  Note  that  er‐
             rors of getopt(1) are still reported as coming from getopt.

      -o, --options shortopts
             The  short  (one-character) options to be recognized.  If this option is not found, the first
             parameter of getopt that does not start with a '-' (and is not an option argument) is used as
             the  short  options  string.  Each short option character in shortopts may be followed by one
             colon to indicate it has a required argument, and by two colons to indicate  it  has  an  op‐
             tional argument.  The first character of shortopts may be '+' or '-' to influence the way op‐
             tions are parsed and output is generated (see section SCANNING MODES for details).

      -q, --quiet
             Disable error reporting by getopt(3).

      -Q, --quiet-output
             Do not generate normal output.  Errors are still reported by getopt(3), unless you  also  use
             -q.

      -s, --shell shell
             Set  quoting  conventions to those of shell.  If the -s option is not given, the BASH conven‐
             tions are used.  Valid arguments are currently 'sh' 'bash', 'csh', and 'tcsh'.

      -T, --test
             Test if your getopt(1) is this enhanced version or an old version.  This generates no output,
             and  sets the error status to 4.  Other implementations of getopt(1), and this version if the
             environment variable GETOPT_COMPATIBLE is set, will return '--' and error status 0.

      -u, --unquoted
             Do not quote the output.  Note that whitespace and special (shell-dependent)  characters  can
             cause havoc in this mode (like they do with other getopt(1) implementations).

      -V, --version
             Display version information and exit.  No other output is generated.

PARSING

      This  section specifies the format of the second part of the parameters of getopt (the parameters in
      the SYNOPSIS).  The next section (OUTPUT) describes the output that is generated.  These  parameters
      were typically the parameters a shell function was called with.  Care must be taken that each param‐
      eter the shell function was called with corresponds to exactly one parameter in the  parameter  list
      of getopt (see the EXAMPLES).  All parsing is done by the GNU getopt(3) routines.

      The  parameters  are  parsed  from left to right.  Each parameter is classified as a short option, a
      long option, an argument to an option, or a non-option parameter.

      A simple short option is a '-' followed by a short option character.  If the option has  a  required
      argument, it may be written directly after the option character or as the next parameter (i.e., sep‐
      arated by whitespace on the command line).  If the option has an optional argument, it must be writ‐
      ten directly after the option character if present.

      It  is  possible to specify several short options after one '-', as long as all (except possibly the
      last) do not have required or optional arguments.

      A long option normally begins with '--' followed by the long option name.  If the option has  a  re‐
      quired  argument, it may be written directly after the long option name, separated by '=', or as the
      next argument (i.e., separated by whitespace on the command line).  If the option  has  an  optional
      argument,  it  must be written directly after the long option name, separated by '=', if present (if
      you add the '=' but nothing behind it, it is interpreted as if no argument was present;  this  is  a
      slight  bug, see the BUGS).  Long options may be abbreviated, as long as the abbreviation is not am‐
      biguous.

      Each parameter not starting with a '-', and not a required argument  of  a  previous  option,  is  a
      non-option  parameter.   Each parameter after a '--' parameter is always interpreted as a non-option
      parameter.  If the environment variable POSIXLY_CORRECT is  set,  or  if  the  short  option  string
      started with a '+', all remaining parameters are interpreted as non-option parameters as soon as the
      first non-option parameter is found.

OUTPUT

      Output is generated for each element described in the previous section.  Output is done in the  same
      order  as  the elements are specified in the input, except for non-option parameters.  Output can be
      done in compatible (unquoted) mode, or in such way that  whitespace  and  other  special  characters
      within  arguments  and  non-option  parameters are preserved (see QUOTING).  When the output is pro‐
      cessed in the shell script, it will seem to be composed of distinct elements that can  be  processed
      one  by  one  (by  using  the shift command in most shell languages).  This is imperfect in unquoted
      mode, as elements can be split at unexpected places if they contain whitespace  or  special  charac‐
      ters.

      If  there  are problems parsing the parameters, for example because a required argument is not found
      or an option is not recognized, an error will be reported on stderr, there will be no output for the
      offending element, and a non-zero error status is returned.

      For  a  short  option, a single '-' and the option character are generated as one parameter.  If the
      option has an argument, the next parameter will be the argument.  If the option  takes  an  optional
      argument, but none was found, the next parameter will be generated but be empty in quoting mode, but
      no second parameter will be generated in unquoted (compatible) mode.  Note that many other getopt(1)
      implementations do not support optional arguments.

      If  several short options were specified after a single '-', each will be present in the output as a
      separate parameter.

      For a long option, '--' and the full option name are generated as one parameter.  This is  done  re‐
      gardless  whether the option was abbreviated or specified with a single '-' in the input.  Arguments
      are handled as with short options.

      Normally, no non-option parameters output is generated until all options and  their  arguments  have
      been  generated.   Then '--' is generated as a single parameter, and after it the non-option parame‐
      ters in the order they were found, each as a separate parameter.  Only if the first character of the
      short options string was a '-', non-option parameter output is generated at the place they are found
      in the input (this is not supported if the first format of the SYNOPSIS is used; in  that  case  all
      preceding occurrences of '-' and '+' are ignored).

QUOTING

      In compatible mode, whitespace or 'special' characters in arguments or non-option parameters are not
      handled correctly.  As the output is fed to the shell script, the script does not  know  how  it  is
      supposed to break the output into separate parameters.  To circumvent this problem, this implementa‐
      tion offers quoting.  The idea is that output is generated with quotes around each parameter.   When
      this  output is once again fed to the shell (usually by a shell eval command), it is split correctly
      into separate parameters.

      Quoting is not enabled if the environment variable GETOPT_COMPATIBLE is set, if the  first  form  of
      the SYNOPSIS is used, or if the option '-u' is found.

      Different shells use different quoting conventions.  You can use the '-s' option to select the shell
      you are using.  The following shells are currently supported: 'sh', 'bash', 'csh' and 'tcsh'.  Actu‐
      ally, only two 'flavors' are distinguished: sh-like quoting conventions and csh-like quoting conven‐
      tions.  Chances are that if you use another shell script language, one of these flavors can still be
      used.

SCANNING MODES

      The first character of the short options string may be a '-' or a '+' to indicate a special scanning
      mode.  If the first calling form in the SYNOPSIS is used they are ignored; the environment  variable
      POSIXLY_CORRECT is still examined, though.

      If  the first character is '+', or if the environment variable POSIXLY_CORRECT is set, parsing stops
      as soon as the first non-option parameter (i.e., a parameter that does not  start  with  a  '-')  is
      found  that  is  not an option argument.  The remaining parameters are all interpreted as non-option
      parameters.

      If the first character is a '-', non-option parameters are outputted at the  place  where  they  are
      found;  in  normal operation, they are all collected at the end of output after a '--' parameter has
      been generated.  Note that this '--' parameter is still generated, but it will always  be  the  last
      parameter in this mode.

COMPATIBILITY

      This version of getopt(1) is written to be as compatible as possible to other versions.  Usually you
      can just replace them with this version without any modifications, and with some advantages.

      If the first character of the first parameter of getopt is not a '-', getopt goes into compatibility
      mode.  It will interpret its first parameter as the string of short options, and all other arguments
      will be parsed.  It will still do parameter shuffling (i.e., all non-option parameters are output at
      the end), unless the environment variable POSIXLY_CORRECT is set.

      The environment variable GETOPT_COMPATIBLE forces getopt into compatibility mode.  Setting both this
      environment variable and POSIXLY_CORRECT offers 100% compatibility for 'difficult'  programs.   Usu‐
      ally, though, neither is needed.

      In compatibility mode, leading '-' and '+' characters in the short options string are ignored.

RETURN CODES

      getopt  returns error code 0 for successful parsing, 1 if getopt(3) returns errors, 2 if it does not
      understand its own parameters, 3 if an internal error occurs like out-of-memory,  and  4  if  it  is
      called with -T.

EXAMPLES

      Example  scripts  for  (ba)sh  and  (t)csh are provided with the getopt(1) distribution, and are in‐
      stalled in /usr/share/doc/util-linux/getopt/ directory.

ENVIRONMENT

      POSIXLY_CORRECT
             This environment variable is examined by the getopt(3) routines.  If it is set, parsing stops
             as  soon  as a parameter is found that is not an option or an option argument.  All remaining
             parameters are also interpreted as non-option parameters, regardless whether they start  with
             a '-'.

      GETOPT_COMPATIBLE
             Forces getopt to use the first calling format as specified in the SYNOPSIS.

BUGS

      getopt(3)  can  parse long options with optional arguments that are given an empty optional argument
      (but cannot do this for short options).  This getopt(1) treats optional arguments that are empty  as
      if they were not present.

      The  syntax  if you do not want any short option variables at all is not very intuitive (you have to
      set them explicitly to the empty string).

AUTHOR

      Frodo Looijaard ⟨frodo@frodo.looijaard.name⟩

SEE ALSO

      bash(1), tcsh(1), getopt(3)

AVAILABILITY

      The getopt command is part of the util-linux package and is  available  from  Linux  Kernel  Archive
      ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.