Getopt::Std(3pm)

💅 Getopt::Std — the manual page, but make it make sense

okay so this is the Getopt::Std(3pm) page from the Perl Programmers Reference Guide, and bestie, we're gonna get you comfy with single-character switches and switch clustering. no cap, it's lowkey iconic. 🎀

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✨ NAME ✨

Getopt::Std — process single-character switches with switch clustering 🦋

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🌸 SYNOPSIS 🌸

use Getopt::Std;

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

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💖 DESCRIPTION 💖

The getopts() function processes single-character switches with switch clustering. You pass it one argument: a string containing all the switches you want it to recognize. 🫶

For each switch it finds:

• 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 that take an argument don't care whether there's a space between the switch and the argument. iconic behavior, honestly. ✨

If unspecified switches are found on the command-line, the user will be warned that an unknown option was given. not me being the friend who tells you your flag is fake 😭

getopts() returns true unless an invalid option was found. periodt.

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. like, it's giving deprecated energy, ngl. 💀

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. very main character energy for people who hate globals 💅

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. slay, a little escape hatch. 🌈

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🧚 "--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. so helpful, fr fr.

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. like please, bestie, set it. the paranoia is not the vibe. 🙈

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 help_mess() and version_mess() with the switches string as an argument. cute little manual override, iykyk. 💜

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made with 💖 from perl v5.42.3, dated 2026-11-03 — that's the footer, bestie, and it ate. 🍓