App::Cmd::Simple(3)

💖 App::Cmd::Simple 💖

okay bestie, so this is App::Cmd::Simple — a lil helper module for building one-command App::Cmd applications ✨ (from the User Contributed Perl Documentation, iykyk 🫶)

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✨ NAME ✨

App::Cmd::Simple — a helper for building one-command App::Cmd applications 💅

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🌸 VERSION 🌸

version 0.338

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🦋 SYNOPSIS 🦋

first up, inside simplecmd:

use YourApp::Cmd;
Your::Cmd->run;

then in YourApp/Cmd.pm:

package YourApp::Cmd 0.01;
use parent qw(App::Cmd::Simple);

sub opt_spec {
  return (
    [ "blortex|X",  "use the blortex algorithm" ],
    [ "recheck|r",  "recheck all results"       ],
  );
}

sub validate_args {
  my ($self, $opt, $args) = @_;

  # no args allowed but options!
  $self->usage_error("No args allowed") if @$args;
}

sub execute {
  my ($self, $opt, $args) = @_;

  my $result = $opt->{blortex} ? blortex() : blort();

  recheck($result) if $opt->{recheck};

  print $result;
}

and, finally, at the command line 🎀:

knight!rjbs$ simplecmd --recheck

All blorts successful.

no cap, that's the whole vibe ✨

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🐚 PERL VERSION 🐚

This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.

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👑 SUBCLASSING 👑

When you're writing a subclass of App::Cmd:Simple, there are only a few methods you might wanna implement. They behave just like the same-named methods in App::Cmd. periodt 💅

⭐ opt_spec

This method should be overridden to provide option specifications. (This is the list of arguments passed to describe_options from Getopt::Long::Descriptive, after the first.)

If it's not overridden, it returns an empty list.

⭐ usage_desc

This method should be overridden to provide the top level usage line. It's a one-line summary of how the command is to be invoked, and it should be given in the format used for the $usage_desc parameter to describe_options in Getopt::Long::Descriptive.

If it's not overridden, it returns something that prints out like:

yourapp [-?h] [long options...]

⭐ validate_args

$cmd->validate_args(\%opt, \@args);

This method gets passed a hashref of command line options (as processed by Getopt::Long::Descriptive) and an arrayref of leftover arguments. It may throw an exception (preferably by calling usage_error) if they're invalid, or it may do nothing and let processing continue. slay 🌈

⭐ execute

Your::App::Cmd::Simple->execute(\%opt, \@args);

This method does whatever it is the command should do! It gets passed a hash reference of the parsed command-line options and an array reference of left over arguments. main character energy fr fr 💅

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💀 WARNINGS 💀

This should be considered experimental! Although it's probably not going to change much, don't build your business model around it yet, okay? 😭

App::Cmd::Simple is not rich in black magic, but it does do some somewhat gnarly things to make an App::Cmd::Simple look as much like an App::Cmd::Command as possible. This means you can't deviate too much from the sort of thing shown in the synopsis, even if you'd like to. If you're doing something other than writing a fairly simple command, and you wanna screw around with the App::Cmd-iness of your program, Simple might not be the best choice.

One specific warning… ⚠️ if you are writing a program with the App::Cmd::Simple class embedded in it, you must call import on the class. That's how things work. You can just do this:

YourApp::Cmd->import->run;

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🫶 AUTHOR 🫶

Ricardo Signes <cpan@semiotic.systems>

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🎀 COPYRIGHT AND LICENSE 🎀

This software is copyright (c) 2025 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

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and that's the tea bestie 🍓 this was perl v5.42.0, dated 2026-01-16, straight from the App::Cmd::Simple(3) page — ily, go build something iconic 👑💜