Getopt::Std(3pm) Perl Programmers Reference Guide Getopt::Std(3pm)
NAME
getopt, getopts - Process single-character switches with switch clustering
SYNOPSIS
use Getopt::Std;
getopt('oDI'); # -o, -D & -I take arg. Sets $opt_* as a side effect.
getopt('oDI', \%opts); # -o, -D & -I take arg. Values in %opts
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
DESCRIPTION
The getopt() function processes single-character switches with switch clustering. Pass one argument
which is a string containing all switches that take an argument. For each switch found, sets $opt_x
(where x is the switch name) to the value of the argument if an argument is expected, or 1 otherwise.
Switches which take an argument don't care whether there is a space between the switch and the argu-ment. argument.
ment.
The getopts() function is similar, but you should pass to it the list of all switches to be recog-nized. recognized.
nized. If unspecified switches are found on the command-line, the user will be warned that an
unknown option was given.
Note that, if your code is running under the recommended "use strict 'vars'" pragma, you will need to
declare these package variables with "our":
our($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.
"--help" and "--version"
If "-" is not a recognized switch letter, getopts() 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 recom-mended recommended
mended 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 func-tions functions
tions help_mess() and version_mess() with the switches string as an argument.
perl v5.8.8 2001-09-21 Getopt::Std(3pm)
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