xenial (1) getopt_long.1.gz

NAME

     getopts — libbash library for command line parameters parsing

SYNOPSIS

     $retval getopt_long ⟨Instructions⟩ ⟨Parameters⟩

DESCRIPTION

     This is a documentation for libbash getopts library, that implements getopt_long function for bash(1).  For
     documentation of bash getopts function, please see getopts(1) ( getopts(1posix) on some systems).

     Here is a table for reference:
     getopts(1)        (or 1posix on some systems) implemented by bash
     getopts(3)        implemented by libbash.
     getopt(1)         implemented by getopt utils (part of util-linux)
     getopt_long(1)    implemented by libbash and installed to section 1 instead of 3 to prevent collision  with
                       C man pages.
     getopt(3)         implemented by GNU C library.
     getopt_long(3)    implemented by GNU C library.
     I have also seen separate getopt utility which part of util-linux package.

     The  getopt_long function parses the command line arguments.  It uses Instructions as the rules for parsing
     the Parameters.

   The Instructions
     A string that specifies rules for parameters parsing.  The instructions string is built of a group of
     independent instructions, separated by a white space.  Each instruction must have the following structure:

     -<SingleLetter>|--<MultiLetter>-><VariableName>[:]

     This structure contains three parts:

     -<SingleLetter>
            This is the parameter single-letter sign. For example -h.

     --<MultiLetter>
            This is the parameter's corresponding multi-letter sign. For example --help.

     <VariableName>[:]
            This is the name of the variable that will contain the parameter value. For example: HELP.

            The Variable name can represent one of two variables types:

            Flag variable (not followed by ‘:’)
                 In this case, it will hold the value 1 if ‘on’ (i.e. was specified on command line) and will
                 not be defined if ‘off’.

            Value variable (followed by ‘:’)
                 In this case, the value it will hold is the string that was given as the next parameter in the
                 Parameters string (Separated by white-space or ‘=’ ). If input contains more then one instance
                 of the considered command line option, an array of the given parameters will be set as the
                 value of the variable.

   The Parameters
     The Parameters are simply the parameters you wish to parse.

RETURN VALUE

     This function returns a string that contains a set of variables definitions.  In order to define the
     variables, this string should be given as a parameter to eval function. This value is returned in the
     variable $retval.

EXAMPLES

     Parse command line parameters looking for the flags -h | --help and -v | --version and for the value -p |
     --path :

           getopt_long '-h|--help->HELP
                         -v|--version->VERSION
                         -p|--path->PATH:' $*
           eval $retval

     In this example, for the parameters --help --path=/usr/ the variables that will be created are:

           HELP=1
           PATH=/usr/

     for the parameters --help --path=/usr --path=/bin the variables that will be created are:

           HELP=1
           PATH=(/usr /bin)

BUGS

     Values must not contain the string `__getopts__'. This string will be parsed as a single white-space.

     A value should not start with an already defined multi-letter sign. If such a  value  exists,  it  will  be
     treated  as  the  equivalent singe-letter sign. This bug only accures when using a single-letter sign, or a
     multi-letter sign that are not followed by a `='.

     For example: If we have a script named `foo', and we parse the  parameters  `-d|--dir:'  and  `-f|--file:',
     then

           foo -d --file
     and

           foo --dir --file
     will not work

           foo --dir=--file
     will work.

AUTHORS

     Hai Zaar <haizaar@haizaar.com>
     Gil Ran <gil@ran4.net>

SEE ALSO

     ldbash(1), getopt_long(1), getopts(1), getopt(1), libbash(1), getopt(3), getopt_long(3)