Provided by: util-linux_2.17.2-9.1ubuntu4_i386 bug

NAME

       getopt - parse command options (enhanced)

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 legal 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   parse   (options   and
       -o|--options  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  its  first
       parameter  is  not  an  option  (does not start with a `-', this is 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  recognize  optional  arguments  (see  section
       COMPATIBILITY for more information).

       Traditional  implementations  of  getopt(1)  are  unable  to  cope with
       whitespace and other (shell-specific) special characters  in  arguments
       and  non-option  parameters. To solve this problem, this implementation
       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 option (-T) can be used.

OPTIONS

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

       -h, --help
              Output  a  small  usage  guide  and  exit successfully. No other
              output is generated.

       -l, --longoptions longopts
              The long (multi-character) options to be recognized.  More  than
              one  option  name  may  be  specified 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 argument.

       -n, --name progname
              The  name  that  will  be used by the getopt(3) routines when it
              reports errors. Note that errors 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  optional
              argument.  The first character of shortopts may be `+' or `-' to
              influence the way options 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 no -s argument  is
              found,  the  BASH  conventions  are  used.  Valid  arguments are
              currently `sh' `bash', `csh', and `tcsh'.

       -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).

       -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.

       -V, --version
              Output version  information  and  exit  successfully.  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  parameter 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  (ie. separated by
       whitespace on  the  command  line).  If  the  option  has  an  optional
       argument,  it  must  be  written 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  required  argument,  it may be written
       directly after the long option name, separated by `=', or as  the  next
       argument  (ie.  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 ambiguous.

       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 processed 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
       characters.

       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 regardless 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 parameters 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  implementation  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'.  Actually, only
       two  `flavors'  are  distinguished:  sh-like  quoting  conventions  and
       csh-like quoting conventions. 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  (ie.  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  (ie.  all  non-option
       parameters  are  outputted 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.
       Usually, 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  optionally  installed  in  /usr/share/doc/util-
       linux/examples.

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 can not 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

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

AVAILABILITY

       The getopt  command  is  part  of  the  util-linux-ng  package  and  is
       available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.