Getopt::Std(3p) Perl Programmers Reference Guide Getopt::Std(3p) #

Getopt::Std(3p) Perl Programmers Reference Guide Getopt::Std(3p)

NNAAMMEE #

 Getopt::Std - Process single-character switches with switch clustering

SSYYNNOOPPSSIISS #

     use Getopt::Std;

     getopts('oif:');  # -o & -i are boolean flags, -f takes an argument
                       # Sets $opt_* as a side effect.
     getopts('oif:', \%opts);  # options as above. Values in %opts
     getopt('oDI');    # -o, -D & -I take arg.
                       # Sets $opt_* as a side effect.
     getopt('oDI', \%opts);    # -o, -D & -I take arg.  Values in %opts

DDEESSCCRRIIPPTTIIOONN #

 The "getopts()" function processes single-character switches with switch
 clustering.  Pass one argument which is a string containing all switches
 to be recognized.  For each switch found, if an argument is expected and
 provided, "getopts()" sets $opt_x (where "x" is the switch name) to the
 value of the argument.  If an argument is expected but none is provided,
 $opt_x is set to an undefined value.  If a switch does not take an
 argument, $opt_x is set to 1.

 Switches which take an argument don't care whether there is a space
 between the switch and the argument.  If unspecified switches are found
 on the command-line, the user will be warned that an unknown option was
 given.

 The "getopts()" function returns true unless an invalid option was found.

 The "getopt()" function is similar, but its argument is a string
 containing all switches that take an argument.  If no argument is
 provided for a switch, say, "y", the corresponding $opt_y will be set to
 an undefined value.  Unspecified switches are silently accepted.  Use of
 "getopt()" is not recommended.

 Note that, if your code is running under the recommended "use strict
 vars" pragma, you will need to declare these package variables with
 "our":

     our($opt_x, $opt_y);

 For those of you who don't like additional global variables being
 created, "getopt()" and "getopts()" will also accept a hash reference as
 an optional second argument.  Hash keys will be "x" (where "x" is the
 switch name) with key values the value of the argument or 1 if no
 argument is specified.

 To allow programs to process arguments that look like switches, but
 aren't, both functions will stop processing switches when they see the
 argument "--".  The "--" will be removed from @ARGV.

“”-–-hheellpp"" aanndd “”-–-vveerrssiioonn"" If “-” is not a recognized switch letter, ggeettooppttss(()) supports arguments “–help” and “–version”. If “main::HELP_MESSAGE()” and/or “main::VERSION_MESSAGE()” are defined, they are called; the arguments are the output file handle, the name of option-processing package, its version, and the switches string. If the subroutines are not defined, an attempt is made to generate intelligent messages; for best results, define $main::VERSION.

 If embedded documentation (in pod format, see perlpod) is detected in the
 script, "--help" will also show how to access the documentation.

 Note that due to excessive paranoia, if
 $Getopt::Std::STANDARD_HELP_VERSION isn't true (the default is false),
 then the messages are printed on STDERR, and the processing continues
 after the messages are printed.  This being the opposite of the standard-
 conforming behaviour, it is strongly recommended to set
 $Getopt::Std::STANDARD_HELP_VERSION to true.

 One can change the output file handle of the messages by setting
 $Getopt::Std::OUTPUT_HELP_VERSION.  One can print the messages of
 "--help" (without the "Usage:" line) and "--version" by calling functions
 hheellpp__mmeessss(()) and vveerrssiioonn__mmeessss(()) with the switches string as an argument.

perl v5.36.3 2023-02-15 Getopt::Std(3p)