use Pod::Usage
my $message_text = "This text precedes the usage message.";
my $exit_status = 2; ## The exit status to use
my $verbose_level = 0; ## The verbose level to use
my $filehandle = \*STDERR; ## The filehandle to write to
pod2usage($message_text);
pod2usage($exit_status);
pod2usage( { -message => $message_text ,
-exitval => $exit_status ,
-verbose => $verbose_level,
-output => $filehandle } );
pod2usage( -msg => $message_text ,
-exitval => $exit_status ,
-verbose => $verbose_level,
-output => $filehandle );
pod2usage( -verbose => 2,
-noperldoc => 1 );
pod2usage( -verbose => 2,
-perlcmd => $path_to_perl,
-perldoc => $path_to_perldoc,
-perldocopt => $perldoc_options );
If more than one argument is given then the entire argument list is assumed to be a hash. If a hash is supplied (either as a reference or as a list) it should contain one or more elements with the following keys:
The special verbosity level 99 requires to also specify the -sections parameter; then these sections are extracted and printed.
"NAME|SYNOPSIS|DESCRIPTION|VERSION"
With the above regexp all content following (and including) any of the given "=head1" headings will be shown. It is possible to restrict the output to particular subsections only, e.g.:
"DESCRIPTION/Algorithm"
This will output only the "=head2 Algorithm" heading and content within the "=head1 DESCRIPTION" section. The regexp binding is stronger than the section separator, such that e.g.:
"DESCRIPTION|OPTIONS|ENVIORNMENT/Caveats"
will print any "=head2 Caveats" section (only) within any of the three "=head1" sections.
Alternatively, an array reference of section specifications can be used:
pod2usage(-verbose => 99, -sections => [
qw(DESCRIPTION DESCRIPTION/Introduction) ] );
This will print only the content of "=head1 DESCRIPTION" and the "=head2 Introduction" sections, but no other "=head2", and no other "=head1" either.
If you are calling pod2usage() from a module and want to display that module's POD, you can use this:
use Pod::Find qw(pod_where);
pod2usage( -input => pod_where({-inc => 1}, __PACKAGE__) );
BEGIN { $Pod::Usage::Formatter = 'Pod::Text::Termcap'; }
use Pod::Usage qw(pod2usage);
Pod::Usage uses Pod::Simple's _handle_element_end() method to implement the section selection, and in case of verbosity < 2 it down-cases the all-caps headings to first capital letter and rest lowercase, and adds a colon/newline at the end of the headings, for better readability. Same for verbosity = 99.
alt code indent loose margin quotes sentence stderr utf8 width
Unless they are explicitly specified, the default values for the exit status, verbose level, and output stream to use are determined as follows:
Although the above may seem a bit confusing at first, it generally does ``the right thing'' in most situations. This determination of the default values to use is based upon the following typical Unix conventions:
pod2usage doesn't force the above conventions upon you, but it will use them by default if you don't expressly tell it to do otherwise. The ability of pod2usage() to accept a single number or a string makes it convenient to use as an innocent looking error message handling function:
use strict;
use Pod::Usage;
use Getopt::Long;
## Parse options
my %opt;
GetOptions(\%opt, "help|?", "man", "flag1") || pod2usage(2);
pod2usage(1) if ($opt{help});
pod2usage(-exitval => 0, -verbose => 2) if ($opt{man});
## Check for too many filenames
pod2usage("$0: Too many files given.\n") if (@ARGV > 1);
Some user's however may feel that the above ``economy of expression'' is not particularly readable nor consistent and may instead choose to do something more like the following:
use strict;
use Pod::Usage qw(pod2usage);
use Getopt::Long qw(GetOptions);
## Parse options
my %opt;
GetOptions(\%opt, "help|?", "man", "flag1") ||
pod2usage(-verbose => 0);
pod2usage(-verbose => 1) if ($opt{help});
pod2usage(-verbose => 2) if ($opt{man});
## Check for too many filenames
pod2usage(-verbose => 2, -message => "$0: Too many files given.\n")
if (@ARGV > 1);
As with all things in Perl, there's more than one way to do it, and pod2usage() adheres to this philosophy. If you are interested in seeing a number of different ways to invoke pod2usage (although by no means exhaustive), please refer to ``EXAMPLES''.
pod2usage();
pod2usage(2);
pod2usage(-verbose => 0);
pod2usage(-exitval => 2);
pod2usage({-exitval => 2, -output => \*STDERR});
pod2usage({-verbose => 0, -output => \*STDERR});
pod2usage(-exitval => 2, -verbose => 0);
pod2usage(-exitval => 2, -verbose => 0, -output => \*STDERR);
Each of the following invocations of "pod2usage()" will print a message of ``Syntax error.'' (followed by a newline) to "STDERR", immediately followed by just the ``SYNOPSIS'' section (also printed to "STDERR") and will exit with a status of 2:
pod2usage("Syntax error.");
pod2usage(-message => "Syntax error.", -verbose => 0);
pod2usage(-msg => "Syntax error.", -exitval => 2);
pod2usage({-msg => "Syntax error.", -exitval => 2, -output => \*STDERR});
pod2usage({-msg => "Syntax error.", -verbose => 0, -output => \*STDERR});
pod2usage(-msg => "Syntax error.", -exitval => 2, -verbose => 0);
pod2usage(-message => "Syntax error.",
-exitval => 2,
-verbose => 0,
-output => \*STDERR);
Each of the following invocations of "pod2usage()" will print the ``SYNOPSIS'' section and any ``OPTIONS'' and/or ``ARGUMENTS'' sections to "STDOUT" and will exit with a status of 1:
pod2usage(1);
pod2usage(-verbose => 1);
pod2usage(-exitval => 1);
pod2usage({-exitval => 1, -output => \*STDOUT});
pod2usage({-verbose => 1, -output => \*STDOUT});
pod2usage(-exitval => 1, -verbose => 1);
pod2usage(-exitval => 1, -verbose => 1, -output => \*STDOUT});
Each of the following invocations of "pod2usage()" will print the entire manual page to "STDOUT" and will exit with a status of 1:
pod2usage(-verbose => 2);
pod2usage({-verbose => 2, -output => \*STDOUT});
pod2usage(-exitval => 1, -verbose => 2);
pod2usage({-exitval => 1, -verbose => 2, -output => \*STDOUT});
use strict;
use Getopt::Long qw(GetOptions);
use Pod::Usage qw(pod2usage);
my $man = 0;
my $help = 0;
## Parse options and print usage if there is a syntax error,
## or if usage was explicitly requested.
GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
pod2usage(1) if $help;
pod2usage(-verbose => 2) if $man;
## If no arguments were given, then allow STDIN to be used only
## if it's not connected to a terminal (otherwise print usage)
pod2usage("$0: No files given.") if ((@ARGV == 0) && (-t STDIN));
__END__
=head1 NAME
sample - Using GetOpt::Long and Pod::Usage
=head1 SYNOPSIS
sample [options] [file ...]
Options:
-help brief help message
-man full documentation
=head1 OPTIONS
=over 4
=item B<-help>
Print a brief help message and exits.
=item B<-man>
Prints the manual page and exits.
=back
=head1 DESCRIPTION
B<This program> will read the given input file(s) and do something
useful with the contents thereof.
=cut
pod2usage(-exitval => 2, -input => "/path/to/your/pod/docs");
In the pathological case that a script is called via a relative path and the script itself changes the current working directory (see ``chdir'' in perlfunc) before calling pod2usage, Pod::Usage will fail even on robust platforms. Don't do that. Or use FindBin to locate the script:
use FindBin;
pod2usage(-input => $FindBin::Bin . "/" . $FindBin::Script);
Marek Rouchal <marekr@cpan.org>
Brad Appleton <bradapp@enteract.com>
Based on code for Pod::Text::pod2text() written by Tom Christiansen <tchrist@mox.perl.com>
Steven McDougall <swmcd@world.std.com> for his help and patience with re-writing this manpage.
Pod::Perldoc, Getopt::Long, Pod::Find, FindBin, Pod::Text, Pod::Text::Termcap, Pod::Simple