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App::Cmd::Command::help(3pm) User Contributed Perl Documentation App::Cmd::Command::help(3pm)


App::Cmd::Command::help - display a command's help screen


version 0.331


This command will either list all of the application commands and their abstracts, or display the usage screen for a subcommand with its description.


The help text is generated from three sources:

  • The "usage_desc" method
  • The "description" method
  • The "opt_spec" data structure

The "usage_desc" method provides the opening usage line, following the specification described in Getopt::Long::Descriptive. In some cases, the default "usage_desc" in App::Cmd::Command may be sufficient and you will only need to override it to provide additional command line usage information.

The "opt_spec" data structure is used with Getopt::Long::Descriptive to generate the description of the options.

Subcommand classes should override the "discription" method to provide additional information that is prepended before the option descriptions.

For example, consider the following subcommand module:

  package YourApp::Command::initialize;
  # This is the default from App::Cmd::Command
  sub usage_desc {
    my ($self) = @_;
    my $desc = $self->SUPER::usage_desc; # "%c COMMAND %o"
    return "$desc [DIRECTORY]";
  sub description {
    return "The initialize command prepares the application...";
  sub opt_spec {
    return (
      [ "skip-refs|R",  "skip reference checks during init", ],
      [ "values|v=s@",  "starting values", { default => [ 0, 1, 3 ] } ],

That module would generate help output like this:

  $ yourapp help initialize
  yourapp initialize [-Rv] [long options...] [DIRECTORY]
  The initialize command prepares the application...
        --help            This usage screen
        -R --skip-refs    skip reference checks during init
        -v --values       starting values


Ricardo Signes <>


This software is copyright (c) 2016 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.

2016-07-18 perl v5.22.2