NAME
   Pod::Usage - extracts POD documentation and shows usage information

SYNOPSIS
     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 );

ARGUMENTS
   pod2usage should be given either a single argument, or a list of
   arguments corresponding to an associative array (a "hash"). When a
   single argument is given, it should correspond to exactly one of the
   following:

   *   A string containing the text of a message to print *before* printing
       the usage message

   *   A numeric value corresponding to the desired exit status

   *   A reference to a hash

   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:

   "-message" *string*
   "-msg" *string*
       The text of a message to print immediately prior to printing the
       program's usage message.

   "-exitval" *value*
       The desired exit status to pass to the exit() function. This should
       be an integer, or else the string "NOEXIT" to indicate that control
       should simply be returned without terminating the invoking process.

   "-verbose" *value*
       The desired level of "verboseness" to use when printing the usage
       message. If the value is 0, then only the "SYNOPSIS" and/or "USAGE"
       sections of the pod documentation are printed. If the value is 1,
       then the "SYNOPSIS" and/or "USAGE" sections, along with any section
       entitled "OPTIONS", "ARGUMENTS", or "OPTIONS AND ARGUMENTS" is
       printed. If the corresponding value is 2 or more then the entire
       manpage is printed, using perldoc if available; otherwise Pod::Text
       is used for the formatting. For better readability, the all-capital
       headings are downcased, e.g. "SYNOPSIS" => "Synopsis".

       The special verbosity level 99 requires to also specify the
       -sections parameter; then these sections are extracted and printed.

   "-sections" *spec*
       There are two ways to specify the selection. Either a string
       (scalar) representing a selection regexp for sections to be printed
       when -verbose is set to 99, e.g.

         "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|ENVIRONMENT/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.

   "-output" *handle*
       A reference to a filehandle, or the pathname of a file to which the
       usage message should be written. The default is "\*STDERR" unless
       the exit value is less than 2 (in which case the default is
       "\*STDOUT").

   "-input" *handle*
       A reference to a filehandle, or the pathname of a file from which
       the invoking script's pod documentation should be read. It defaults
       to the file indicated by $0 ($PROGRAM_NAME for users of English.pm).

       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__) );

   "-pathlist" *string*
       A list of directory paths. If the input file does not exist, then it
       will be searched for in the given directory list (in the order the
       directories appear in the list). It defaults to the list of
       directories implied by $ENV{PATH}. The list may be specified either
       by a reference to an array, or by a string of directory paths which
       use the same path separator as $ENV{PATH} on your system (e.g., ":"
       for Unix, ";" for MSWin32 and DOS).

   "-noperldoc"
       By default, Pod::Usage will call perldoc when -verbose >= 2 is
       specified. This does not work well e.g. if the script was packed
       with PAR. This option suppresses the external call to perldoc and
       uses the simple text formatter (Pod::Text) to output the POD.

   "-perlcmd"
       By default, Pod::Usage will call perldoc when -verbose >= 2 is
       specified. In case of special or unusual Perl installations, this
       option may be used to supply the path to a perl executable which
       should run perldoc.

   "-perldoc" *path-to-perldoc*
       By default, Pod::Usage will call perldoc when -verbose >= 2 is
       specified. In case perldoc is not installed where the perl
       interpreter thinks it is (see Config), the -perldoc option may be
       used to supply the correct path to perldoc.

   "-perldocopt" *string*
       By default, Pod::Usage will call perldoc when -verbose >= 2 is
       specified. This option may be used to supply options to perldoc. The
       string may contain several, space-separated options.

 Formatting base class
   The default text formatter is Pod::Text. The base class for Pod::Usage
   can be defined by pre-setting $Pod::Usage::Formatter *before* loading
   Pod::Usage, e.g.:

       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.

 Pass-through options
   The following options are passed through to the underlying text
   formatter. See the manual pages of these modules for more information.

     alt code indent loose margin quotes sentence stderr utf8 width

DESCRIPTION
   pod2usage will print a usage message for the invoking script (using its
   embedded pod documentation) and then exit the script with the desired
   exit status. The usage message printed may have any one of three levels
   of "verboseness": If the verbose level is 0, then only a synopsis is
   printed. If the verbose level is 1, then the synopsis is printed along
   with a description (if present) of the command line options and
   arguments. If the verbose level is 2, then the entire manual page is
   printed.

   Unless they are explicitly specified, the default values for the exit
   status, verbose level, and output stream to use are determined as
   follows:

   *   If neither the exit status nor the verbose level is specified, then
       the default is to use an exit status of 2 with a verbose level of 0.

   *   If an exit status *is* specified but the verbose level is *not*,
       then the verbose level will default to 1 if the exit status is less
       than 2 and will default to 0 otherwise.

   *   If an exit status is *not* specified but verbose level *is* given,
       then the exit status will default to 2 if the verbose level is 0 and
       will default to 1 otherwise.

   *   If the exit status used is less than 2, then output is printed on
       "STDOUT". Otherwise output is printed on "STDERR".

   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:

   *   An exit status of 0 implies "success". For example, diff(1) exits
       with a status of 0 if the two files have the same contents.

   *   An exit status of 1 implies possibly abnormal, but non-defective,
       program termination. For example, grep(1) exits with a status of 1
       if it did *not* find a matching line for the given regular
       expression.

   *   An exit status of 2 or more implies a fatal error. For example,
       ls(1) exits with a status of 2 if you specify an illegal (unknown)
       option on the command line.

   *   Usage messages issued as a result of bad command-line syntax should
       go to "STDERR". However, usage messages issued due to an explicit
       request to print usage (like specifying -help on the command line)
       should go to "STDOUT", just in case the user wants to pipe the
       output to a pager (such as more(1)).

   *   If program usage has been explicitly requested by the user, it is
       often desirable to exit with a status of 1 (as opposed to 0) after
       issuing the user-requested usage message. It is also desirable to
       give a more verbose description of program usage in this case.

   pod2usage does not 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".

 Scripts
   The Pod::Usage distribution comes with a script pod2usage which offers a
   command line interface to the functionality of Pod::Usage. See
   pod2usage.

EXAMPLES
   Each of the following invocations of "pod2usage()" will print just the
   "SYNOPSIS" section to "STDERR" and will exit with a status of 2:

       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});

 Recommended Use
   Most scripts should print some type of usage message to "STDERR" when a
   command line syntax error is detected. They should also provide an
   option (usually "-H" or "-help") to print a (possibly more verbose)
   usage message to "STDOUT". Some scripts may even wish to go so far as to
   provide a means of printing their complete documentation to "STDOUT"
   (perhaps by allowing a "-man" option). The following complete example
   uses Pod::Usage in combination with Getopt::Long to do all of these
   things:

       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

CAVEATS
   By default, pod2usage() will use $0 as the path to the pod input file.
   Unfortunately, not all systems on which Perl runs will set $0 properly
   (although if $0 is not found, pod2usage() will search $ENV{PATH} or else
   the list specified by the "-pathlist" option). If this is the case for
   your system, you may need to explicitly specify the path to the pod docs
   for the invoking script using something similar to the following:

       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);

SUPPORT
   This module is managed in a GitHub repository,
   <https://github.com/Dual-Life/Pod-Usage> Feel free to fork and
   contribute, or to clone and send patches!

   Please use <https://github.com/Dual-Life/Pod-Usage/issues/new> to file a
   bug report. The previous ticketing system,
   <https://rt.cpan.org/Dist/Display.html?Queue=Pod-Usage>, is deprecated
   for this package.

   More general questions or discussion about POD should be sent to the
   "[email protected]" mail list. Send an empty email to
   "[email protected]" to subscribe.

AUTHOR
   Marek Rouchal <[email protected]>

   Nicolas R <[email protected]>

   Brad Appleton <[email protected]>

   Based on code for Pod::Text::pod2text() written by Tom Christiansen
   <[email protected]>

LICENSE
   Pod::Usage (the distribution) is licensed under the same terms as Perl.

ACKNOWLEDGMENTS
   Nicolas R (ATOOMIC) for setting up the Github repo and modernizing this
   package.

   rjbs for refactoring Pod::Usage to not use Pod::Parser any more.

   Steven McDougall <[email protected]> for his help and patience with
   re-writing this manpage.

SEE ALSO
   Pod::Usage is now a standalone distribution, depending on Pod::Text
   which in turn depends on Pod::Simple.

   Pod::Perldoc, Getopt::Long, Pod::Find, FindBin, Pod::Text,
   Pod::Text::Termcap, Pod::Simple

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