1#############################################################################
2# Pod/Usage.pm -- print usage messages for the running script.
3#
4# Copyright (C) 1996-2000 by Bradford Appleton. All rights reserved.
5# This file is part of "PodParser". PodParser is free software;
6# you can redistribute it and/or modify it under the same terms
7# as Perl itself.
8#############################################################################
9
10package Pod::Usage;
11use strict;
12
13use vars qw($VERSION @ISA @EXPORT);
14$VERSION = '1.63';  ## Current version of this package
15require  5.006;    ## requires this Perl version or later
16
17#use diagnostics;
18use Carp;
19use Config;
20use Exporter;
21use File::Spec;
22
23@EXPORT = qw(&pod2usage);
24BEGIN {
25    $Pod::Usage::Formatter ||= 'Pod::Text';
26    eval "require $Pod::Usage::Formatter";
27    die $@ if $@;
28    @ISA = ( $Pod::Usage::Formatter );
29}
30
31our $MAX_HEADING_LEVEL = 3;
32
33##---------------------------------------------------------------------------
34
35##---------------------------------
36## Function definitions begin here
37##---------------------------------
38
39sub pod2usage {
40    local($_) = shift;
41    my %opts;
42    ## Collect arguments
43    if (@_ > 0) {
44        ## Too many arguments - assume that this is a hash and
45        ## the user forgot to pass a reference to it.
46        %opts = ($_, @_);
47    }
48    elsif (!defined $_) {
49      $_ = '';
50    }
51    elsif (ref $_) {
52        ## User passed a ref to a hash
53        %opts = %{$_}  if (ref($_) eq 'HASH');
54    }
55    elsif (/^[-+]?\d+$/) {
56        ## User passed in the exit value to use
57        $opts{'-exitval'} =  $_;
58    }
59    else {
60        ## User passed in a message to print before issuing usage.
61        $_  and  $opts{'-message'} = $_;
62    }
63
64    ## Need this for backward compatibility since we formerly used
65    ## options that were all uppercase words rather than ones that
66    ## looked like Unix command-line options.
67    ## to be uppercase keywords)
68    %opts = map {
69        my ($key, $val) = ($_, $opts{$_});
70        $key =~ s/^(?=\w)/-/;
71        $key =~ /^-msg/i   and  $key = '-message';
72        $key =~ /^-exit/i  and  $key = '-exitval';
73        lc($key) => $val;
74    } (keys %opts);
75
76    ## Now determine default -exitval and -verbose values to use
77    if ((! defined $opts{'-exitval'}) && (! defined $opts{'-verbose'})) {
78        $opts{'-exitval'} = 2;
79        $opts{'-verbose'} = 0;
80    }
81    elsif (! defined $opts{'-exitval'}) {
82        $opts{'-exitval'} = ($opts{'-verbose'} > 0) ? 1 : 2;
83    }
84    elsif (! defined $opts{'-verbose'}) {
85        $opts{'-verbose'} = (lc($opts{'-exitval'}) eq 'noexit' ||
86                             $opts{'-exitval'} < 2);
87    }
88
89    ## Default the output file
90    $opts{'-output'} = (lc($opts{'-exitval'}) eq 'noexit' ||
91                        $opts{'-exitval'} < 2) ? \*STDOUT : \*STDERR
92            unless (defined $opts{'-output'});
93    ## Default the input file
94    $opts{'-input'} = $0  unless (defined $opts{'-input'});
95
96    ## Look up input file in path if it doesn't exist.
97    unless ((ref $opts{'-input'}) || (-e $opts{'-input'})) {
98        my $basename = $opts{'-input'};
99        my $pathsep = ($^O =~ /^(?:dos|os2|MSWin32)$/i) ? ';'
100                            : (($^O eq 'MacOS' || $^O eq 'VMS') ? ',' :  ':');
101        my $pathspec = $opts{'-pathlist'} || $ENV{PATH} || $ENV{PERL5LIB};
102
103        my @paths = (ref $pathspec) ? @$pathspec : split($pathsep, $pathspec);
104        for my $dirname (@paths) {
105            $_ = File::Spec->catfile($dirname, $basename)  if length;
106            last if (-e $_) && ($opts{'-input'} = $_);
107        }
108    }
109
110    ## Now create a pod reader and constrain it to the desired sections.
111    my $parser = new Pod::Usage(USAGE_OPTIONS => \%opts);
112    if ($opts{'-verbose'} == 0) {
113        $parser->select('(?:SYNOPSIS|USAGE)\s*');
114    }
115    elsif ($opts{'-verbose'} == 1) {
116        my $opt_re = '(?i)' .
117                     '(?:OPTIONS|ARGUMENTS)' .
118                     '(?:\s*(?:AND|\/)\s*(?:OPTIONS|ARGUMENTS))?';
119        $parser->select( '(?:SYNOPSIS|USAGE)\s*', $opt_re, "DESCRIPTION/$opt_re" );
120    }
121    elsif ($opts{'-verbose'} >= 2 && $opts{'-verbose'} != 99) {
122        $parser->select('.*');
123    }
124    elsif ($opts{'-verbose'} == 99) {
125        my $sections = $opts{'-sections'};
126        $parser->select( (ref $sections) ? @$sections : $sections );
127        $opts{'-verbose'} = 1;
128    }
129
130    ## Check for perldoc
131    my $progpath = File::Spec->catfile($Config{scriptdirexp}
132	|| $Config{scriptdir}, 'perldoc');
133
134    my $version = sprintf("%vd",$^V);
135    if ($Config{versiononly} and $Config{startperl} =~ /\Q$version\E$/ ) {
136      $progpath .= $version;
137    }
138    $opts{'-noperldoc'} = 1 unless -e $progpath;
139
140    ## Now translate the pod document and then exit with the desired status
141    if (      !$opts{'-noperldoc'}
142         and  $opts{'-verbose'} >= 2
143         and  !ref($opts{'-input'})
144         and  $opts{'-output'} == \*STDOUT )
145    {
146       ## spit out the entire PODs. Might as well invoke perldoc
147       print { $opts{'-output'} } ($opts{'-message'}, "\n") if($opts{'-message'});
148       if(defined $opts{-input} && $opts{-input} =~ /^\s*(\S.*?)\s*$/) {
149         # the perldocs back to 5.005 should all have -F
150	 # without -F there are warnings in -T scripts
151         system($progpath, '-F', $1);
152         if($?) {
153           # RT16091: fall back to more if perldoc failed
154           system(($Config{pager} || $ENV{PAGER} || '/bin/more'), $1);
155         }
156       } else {
157         croak "Unspecified input file or insecure argument.\n";
158       }
159    }
160    else {
161       $parser->parse_from_file($opts{'-input'}, $opts{'-output'});
162    }
163
164    exit($opts{'-exitval'})  unless (lc($opts{'-exitval'}) eq 'noexit');
165}
166
167##---------------------------------------------------------------------------
168
169##-------------------------------
170## Method definitions begin here
171##-------------------------------
172
173sub new {
174    my $this = shift;
175    my $class = ref($this) || $this;
176    my %params = @_;
177    my $self = {%params};
178    bless $self, $class;
179    if ($self->can('initialize')) {
180        $self->initialize();
181    } else {
182        # pass through options to Pod::Text
183        my %opts;
184       	for (qw(alt code indent loose margin quotes sentence stderr utf8 width)) {
185            my $val = $params{USAGE_OPTIONS}{"-$_"};
186            $opts{$_} = $val if defined $val;
187        }
188        $self = $self->SUPER::new(%opts);
189        %$self = (%$self, %params);
190    }
191    return $self;
192}
193
194# This subroutine was copied in whole-cloth from Pod::Select 1.60 in order to
195# allow the ejection of Pod::Select from the core without breaking Pod::Usage.
196# -- rjbs, 2013-03-18
197sub _compile_section_spec {
198    my ($section_spec) = @_;
199    my (@regexs, $negated);
200
201    ## Compile the spec into a list of regexs
202    local $_ = $section_spec;
203    s{\\\\}{\001}g;  ## handle escaped backward slashes
204    s{\\/}{\002}g;   ## handle escaped forward slashes
205
206    ## Parse the regexs for the heading titles
207    @regexs = split(/\//, $_, $MAX_HEADING_LEVEL);
208
209    ## Set default regex for ommitted levels
210    for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) {
211        $regexs[$i]  = '.*'  unless ((defined $regexs[$i])
212                                     && (length $regexs[$i]));
213    }
214    ## Modify the regexs as needed and validate their syntax
215    my $bad_regexs = 0;
216    for (@regexs) {
217        $_ .= '.+'  if ($_ eq '!');
218        s{\001}{\\\\}g;       ## restore escaped backward slashes
219        s{\002}{\\/}g;        ## restore escaped forward slashes
220        $negated = s/^\!//;   ## check for negation
221        eval "m{$_}";         ## check regex syntax
222        if ($@) {
223            ++$bad_regexs;
224            carp qq{Bad regular expression /$_/ in "$section_spec": $@\n};
225        }
226        else {
227            ## Add the forward and rear anchors (and put the negator back)
228            $_ = '^' . $_  unless (/^\^/);
229            $_ = $_ . '$'  unless (/\$$/);
230            $_ = '!' . $_  if ($negated);
231        }
232    }
233    return  (! $bad_regexs) ? [ @regexs ] : undef;
234}
235
236sub select {
237    my ($self, @sections) = @_;
238    if ($ISA[0]->can('select')) {
239        $self->SUPER::select(@sections);
240    } else {
241        # we're using Pod::Simple - need to mimic the behavior of Pod::Select
242        my $add = ($sections[0] eq '+') ? shift(@sections) : '';
243        ## Reset the set of sections to use
244        unless (@sections) {
245          delete $self->{USAGE_SELECT} unless ($add);
246          return;
247        }
248        $self->{USAGE_SELECT} = []
249          unless ($add && $self->{USAGE_SELECT});
250        my $sref = $self->{USAGE_SELECT};
251        ## Compile each spec
252        for my $spec (@sections) {
253          my $cs = _compile_section_spec($spec);
254          if ( defined $cs ) {
255            ## Store them in our sections array
256            push(@$sref, $cs);
257          } else {
258            carp qq{Ignoring section spec "$spec"!\n};
259          }
260        }
261    }
262}
263
264# Override Pod::Text->seq_i to return just "arg", not "*arg*".
265sub seq_i { return $_[1] }
266
267# This overrides the Pod::Text method to do something very akin to what
268# Pod::Select did as well as the work done below by preprocess_paragraph.
269# Note that the below is very, very specific to Pod::Text.
270sub _handle_element_end {
271    my ($self, $element) = @_;
272    if ($element eq 'head1') {
273        $self->{USAGE_HEADINGS} = [ $$self{PENDING}[-1][1] ];
274        if ($self->{USAGE_OPTIONS}->{-verbose} < 2) {
275            $$self{PENDING}[-1][1] =~ s/^\s*SYNOPSIS\s*$/USAGE/;
276        }
277    } elsif ($element =~ /^head(\d+)$/ && $1) { # avoid 0
278        my $idx = $1 - 1;
279        $self->{USAGE_HEADINGS} = [] unless($self->{USAGE_HEADINGS});
280        $self->{USAGE_HEADINGS}->[$idx] = $$self{PENDING}[-1][1];
281    }
282    if ($element =~ /^head\d+$/) {
283        $$self{USAGE_SKIPPING} = 1;
284        if (!$$self{USAGE_SELECT} || !@{ $$self{USAGE_SELECT} }) {
285            $$self{USAGE_SKIPPING} = 0;
286        } else {
287            my @headings = @{$$self{USAGE_HEADINGS}};
288            for my $section_spec ( @{$$self{USAGE_SELECT}} ) {
289                my $match = 1;
290                for (my $i = 0; $i < $MAX_HEADING_LEVEL; ++$i) {
291                    $headings[$i] = '' unless defined $headings[$i];
292                    my $regex   = $section_spec->[$i];
293                    my $negated = ($regex =~ s/^\!//);
294                    $match  &= ($negated ? ($headings[$i] !~ /${regex}/)
295                                         : ($headings[$i] =~ /${regex}/));
296                    last unless ($match);
297                } # end heading levels
298                if ($match) {
299                  $$self{USAGE_SKIPPING} = 0;
300                  last;
301                }
302            } # end sections
303        }
304
305        # Try to do some lowercasing instead of all-caps in headings, and use
306        # a colon to end all headings.
307        if($self->{USAGE_OPTIONS}->{-verbose} < 2) {
308            local $_ = $$self{PENDING}[-1][1];
309            s{([A-Z])([A-Z]+)}{((length($2) > 2) ? $1 : lc($1)) . lc($2)}ge;
310            s/\s*$/:/  unless (/:\s*$/);
311            $_ .= "\n";
312            $$self{PENDING}[-1][1] = $_;
313        }
314    }
315    if ($$self{USAGE_SKIPPING} && $element !~ m/^over-/) {
316        pop @{ $$self{PENDING} };
317    } else {
318        $self->SUPER::_handle_element_end($element);
319    }
320}
321
322# required for Pod::Simple API
323sub start_document {
324    my $self = shift;
325    $self->SUPER::start_document();
326    my $msg = $self->{USAGE_OPTIONS}->{-message}  or  return 1;
327    my $out_fh = $self->output_fh();
328    print $out_fh "$msg\n";
329}
330
331# required for old Pod::Parser API
332sub begin_pod {
333    my $self = shift;
334    $self->SUPER::begin_pod();  ## Have to call superclass
335    my $msg = $self->{USAGE_OPTIONS}->{-message}  or  return 1;
336    my $out_fh = $self->output_handle();
337    print $out_fh "$msg\n";
338}
339
340sub preprocess_paragraph {
341    my $self = shift;
342    local $_ = shift;
343    my $line = shift;
344    ## See if this is a heading and we aren't printing the entire manpage.
345    if (($self->{USAGE_OPTIONS}->{-verbose} < 2) && /^=head/) {
346        ## Change the title of the SYNOPSIS section to USAGE
347        s/^=head1\s+SYNOPSIS\s*$/=head1 USAGE/;
348        ## Try to do some lowercasing instead of all-caps in headings
349        s{([A-Z])([A-Z]+)}{((length($2) > 2) ? $1 : lc($1)) . lc($2)}ge;
350        ## Use a colon to end all headings
351        s/\s*$/:/  unless (/:\s*$/);
352        $_ .= "\n";
353    }
354    return  $self->SUPER::preprocess_paragraph($_);
355}
356
3571; # keep require happy
358
359__END__
360
361=head1 NAME
362
363Pod::Usage, pod2usage() - print a usage message from embedded pod documentation
364
365=head1 SYNOPSIS
366
367  use Pod::Usage
368
369  my $message_text  = "This text precedes the usage message.";
370  my $exit_status   = 2;          ## The exit status to use
371  my $verbose_level = 0;          ## The verbose level to use
372  my $filehandle    = \*STDERR;   ## The filehandle to write to
373
374  pod2usage($message_text);
375
376  pod2usage($exit_status);
377
378  pod2usage( { -message => $message_text ,
379               -exitval => $exit_status  ,
380               -verbose => $verbose_level,
381               -output  => $filehandle } );
382
383  pod2usage(   -msg     => $message_text ,
384               -exitval => $exit_status  ,
385               -verbose => $verbose_level,
386               -output  => $filehandle   );
387
388  pod2usage(   -verbose => 2,
389               -noperldoc => 1  )
390
391=head1 ARGUMENTS
392
393B<pod2usage> should be given either a single argument, or a list of
394arguments corresponding to an associative array (a "hash"). When a single
395argument is given, it should correspond to exactly one of the following:
396
397=over 4
398
399=item *
400
401A string containing the text of a message to print I<before> printing
402the usage message
403
404=item *
405
406A numeric value corresponding to the desired exit status
407
408=item *
409
410A reference to a hash
411
412=back
413
414If more than one argument is given then the entire argument list is
415assumed to be a hash.  If a hash is supplied (either as a reference or
416as a list) it should contain one or more elements with the following
417keys:
418
419=over 4
420
421=item C<-message>
422
423=item C<-msg>
424
425The text of a message to print immediately prior to printing the
426program's usage message.
427
428=item C<-exitval>
429
430The desired exit status to pass to the B<exit()> function.
431This should be an integer, or else the string "NOEXIT" to
432indicate that control should simply be returned without
433terminating the invoking process.
434
435=item C<-verbose>
436
437The desired level of "verboseness" to use when printing the usage
438message. If the corresponding value is 0, then only the "SYNOPSIS"
439section of the pod documentation is printed. If the corresponding value
440is 1, then the "SYNOPSIS" section, along with any section entitled
441"OPTIONS", "ARGUMENTS", or "OPTIONS AND ARGUMENTS" is printed.  If the
442corresponding value is 2 or more then the entire manpage is printed.
443
444The special verbosity level 99 requires to also specify the -sections
445parameter; then these sections are extracted and printed.
446
447=item C<-sections>
448
449A string representing a selection list for sections to be printed
450when -verbose is set to 99, e.g. C<"NAME|SYNOPSIS|DESCRIPTION|VERSION">.
451
452Alternatively, an array reference of section specifications can be used:
453
454  pod2usage(-verbose => 99,
455            -sections => [ qw(fred fred/subsection) ] );
456
457=item C<-output>
458
459A reference to a filehandle, or the pathname of a file to which the
460usage message should be written. The default is C<\*STDERR> unless the
461exit value is less than 2 (in which case the default is C<\*STDOUT>).
462
463=item C<-input>
464
465A reference to a filehandle, or the pathname of a file from which the
466invoking script's pod documentation should be read.  It defaults to the
467file indicated by C<$0> (C<$PROGRAM_NAME> for users of F<English.pm>).
468
469If you are calling B<pod2usage()> from a module and want to display
470that module's POD, you can use this:
471
472  use Pod::Find qw(pod_where);
473  pod2usage( -input => pod_where({-inc => 1}, __PACKAGE__) );
474
475=item C<-pathlist>
476
477A list of directory paths. If the input file does not exist, then it
478will be searched for in the given directory list (in the order the
479directories appear in the list). It defaults to the list of directories
480implied by C<$ENV{PATH}>. The list may be specified either by a reference
481to an array, or by a string of directory paths which use the same path
482separator as C<$ENV{PATH}> on your system (e.g., C<:> for Unix, C<;> for
483MSWin32 and DOS).
484
485=item C<-noperldoc>
486
487By default, Pod::Usage will call L<perldoc> when -verbose >= 2 is
488specified. This does not work well e.g. if the script was packed
489with L<PAR>. The -noperldoc option suppresses the external call to
490L<perldoc> and uses the simple text formatter (L<Pod::Text>) to
491output the POD.
492
493=back
494
495=head2 Formatting base class
496
497The default text formatter is L<Pod::Text>.  The base class for Pod::Usage can
498be defined by pre-setting C<$Pod::Usage::Formatter> I<before>
499loading Pod::Usage, e.g.:
500
501    BEGIN { $Pod::Usage::Formatter = 'Pod::Text::Termcap'; }
502    use Pod::Usage qw(pod2usage);
503
504=head2 Pass-through options
505
506The following options are passed through to the underlying text formatter.
507See the manual pages of these modules for more information.
508
509  alt code indent loose margin quotes sentence stderr utf8 width
510
511=head1 DESCRIPTION
512
513B<pod2usage> will print a usage message for the invoking script (using
514its embedded pod documentation) and then exit the script with the
515desired exit status. The usage message printed may have any one of three
516levels of "verboseness": If the verbose level is 0, then only a synopsis
517is printed. If the verbose level is 1, then the synopsis is printed
518along with a description (if present) of the command line options and
519arguments. If the verbose level is 2, then the entire manual page is
520printed.
521
522Unless they are explicitly specified, the default values for the exit
523status, verbose level, and output stream to use are determined as
524follows:
525
526=over 4
527
528=item *
529
530If neither the exit status nor the verbose level is specified, then the
531default is to use an exit status of 2 with a verbose level of 0.
532
533=item *
534
535If an exit status I<is> specified but the verbose level is I<not>, then the
536verbose level will default to 1 if the exit status is less than 2 and
537will default to 0 otherwise.
538
539=item *
540
541If an exit status is I<not> specified but verbose level I<is> given, then
542the exit status will default to 2 if the verbose level is 0 and will
543default to 1 otherwise.
544
545=item *
546
547If the exit status used is less than 2, then output is printed on
548C<STDOUT>.  Otherwise output is printed on C<STDERR>.
549
550=back
551
552Although the above may seem a bit confusing at first, it generally does
553"the right thing" in most situations.  This determination of the default
554values to use is based upon the following typical Unix conventions:
555
556=over 4
557
558=item *
559
560An exit status of 0 implies "success". For example, B<diff(1)> exits
561with a status of 0 if the two files have the same contents.
562
563=item *
564
565An exit status of 1 implies possibly abnormal, but non-defective, program
566termination.  For example, B<grep(1)> exits with a status of 1 if
567it did I<not> find a matching line for the given regular expression.
568
569=item *
570
571An exit status of 2 or more implies a fatal error. For example, B<ls(1)>
572exits with a status of 2 if you specify an illegal (unknown) option on
573the command line.
574
575=item *
576
577Usage messages issued as a result of bad command-line syntax should go
578to C<STDERR>.  However, usage messages issued due to an explicit request
579to print usage (like specifying B<-help> on the command line) should go
580to C<STDOUT>, just in case the user wants to pipe the output to a pager
581(such as B<more(1)>).
582
583=item *
584
585If program usage has been explicitly requested by the user, it is often
586desirable to exit with a status of 1 (as opposed to 0) after issuing
587the user-requested usage message.  It is also desirable to give a
588more verbose description of program usage in this case.
589
590=back
591
592B<pod2usage> doesn't force the above conventions upon you, but it will
593use them by default if you don't expressly tell it to do otherwise.  The
594ability of B<pod2usage()> to accept a single number or a string makes it
595convenient to use as an innocent looking error message handling function:
596
597    use Pod::Usage;
598    use Getopt::Long;
599
600    ## Parse options
601    GetOptions("help", "man", "flag1")  ||  pod2usage(2);
602    pod2usage(1)  if ($opt_help);
603    pod2usage(-verbose => 2)  if ($opt_man);
604
605    ## Check for too many filenames
606    pod2usage("$0: Too many files given.\n")  if (@ARGV > 1);
607
608Some user's however may feel that the above "economy of expression" is
609not particularly readable nor consistent and may instead choose to do
610something more like the following:
611
612    use Pod::Usage;
613    use Getopt::Long;
614
615    ## Parse options
616    GetOptions("help", "man", "flag1")  ||  pod2usage(-verbose => 0);
617    pod2usage(-verbose => 1)  if ($opt_help);
618    pod2usage(-verbose => 2)  if ($opt_man);
619
620    ## Check for too many filenames
621    pod2usage(-verbose => 2, -message => "$0: Too many files given.\n")
622        if (@ARGV > 1);
623
624As with all things in Perl, I<there's more than one way to do it>, and
625B<pod2usage()> adheres to this philosophy.  If you are interested in
626seeing a number of different ways to invoke B<pod2usage> (although by no
627means exhaustive), please refer to L<"EXAMPLES">.
628
629=head1 EXAMPLES
630
631Each of the following invocations of C<pod2usage()> will print just the
632"SYNOPSIS" section to C<STDERR> and will exit with a status of 2:
633
634    pod2usage();
635
636    pod2usage(2);
637
638    pod2usage(-verbose => 0);
639
640    pod2usage(-exitval => 2);
641
642    pod2usage({-exitval => 2, -output => \*STDERR});
643
644    pod2usage({-verbose => 0, -output  => \*STDERR});
645
646    pod2usage(-exitval => 2, -verbose => 0);
647
648    pod2usage(-exitval => 2, -verbose => 0, -output => \*STDERR);
649
650Each of the following invocations of C<pod2usage()> will print a message
651of "Syntax error." (followed by a newline) to C<STDERR>, immediately
652followed by just the "SYNOPSIS" section (also printed to C<STDERR>) and
653will exit with a status of 2:
654
655    pod2usage("Syntax error.");
656
657    pod2usage(-message => "Syntax error.", -verbose => 0);
658
659    pod2usage(-msg  => "Syntax error.", -exitval => 2);
660
661    pod2usage({-msg => "Syntax error.", -exitval => 2, -output => \*STDERR});
662
663    pod2usage({-msg => "Syntax error.", -verbose => 0, -output => \*STDERR});
664
665    pod2usage(-msg  => "Syntax error.", -exitval => 2, -verbose => 0);
666
667    pod2usage(-message => "Syntax error.",
668              -exitval => 2,
669              -verbose => 0,
670              -output  => \*STDERR);
671
672Each of the following invocations of C<pod2usage()> will print the
673"SYNOPSIS" section and any "OPTIONS" and/or "ARGUMENTS" sections to
674C<STDOUT> and will exit with a status of 1:
675
676    pod2usage(1);
677
678    pod2usage(-verbose => 1);
679
680    pod2usage(-exitval => 1);
681
682    pod2usage({-exitval => 1, -output => \*STDOUT});
683
684    pod2usage({-verbose => 1, -output => \*STDOUT});
685
686    pod2usage(-exitval => 1, -verbose => 1);
687
688    pod2usage(-exitval => 1, -verbose => 1, -output => \*STDOUT});
689
690Each of the following invocations of C<pod2usage()> will print the
691entire manual page to C<STDOUT> and will exit with a status of 1:
692
693    pod2usage(-verbose  => 2);
694
695    pod2usage({-verbose => 2, -output => \*STDOUT});
696
697    pod2usage(-exitval  => 1, -verbose => 2);
698
699    pod2usage({-exitval => 1, -verbose => 2, -output => \*STDOUT});
700
701=head2 Recommended Use
702
703Most scripts should print some type of usage message to C<STDERR> when a
704command line syntax error is detected. They should also provide an
705option (usually C<-H> or C<-help>) to print a (possibly more verbose)
706usage message to C<STDOUT>. Some scripts may even wish to go so far as to
707provide a means of printing their complete documentation to C<STDOUT>
708(perhaps by allowing a C<-man> option). The following complete example
709uses B<Pod::Usage> in combination with B<Getopt::Long> to do all of these
710things:
711
712    use Getopt::Long;
713    use Pod::Usage;
714
715    my $man = 0;
716    my $help = 0;
717    ## Parse options and print usage if there is a syntax error,
718    ## or if usage was explicitly requested.
719    GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
720    pod2usage(1) if $help;
721    pod2usage(-verbose => 2) if $man;
722
723    ## If no arguments were given, then allow STDIN to be used only
724    ## if it's not connected to a terminal (otherwise print usage)
725    pod2usage("$0: No files given.")  if ((@ARGV == 0) && (-t STDIN));
726    __END__
727
728    =head1 NAME
729
730    sample - Using GetOpt::Long and Pod::Usage
731
732    =head1 SYNOPSIS
733
734    sample [options] [file ...]
735
736     Options:
737       -help            brief help message
738       -man             full documentation
739
740    =head1 OPTIONS
741
742    =over 8
743
744    =item B<-help>
745
746    Print a brief help message and exits.
747
748    =item B<-man>
749
750    Prints the manual page and exits.
751
752    =back
753
754    =head1 DESCRIPTION
755
756    B<This program> will read the given input file(s) and do something
757    useful with the contents thereof.
758
759    =cut
760
761=head1 CAVEATS
762
763By default, B<pod2usage()> will use C<$0> as the path to the pod input
764file.  Unfortunately, not all systems on which Perl runs will set C<$0>
765properly (although if C<$0> isn't found, B<pod2usage()> will search
766C<$ENV{PATH}> or else the list specified by the C<-pathlist> option).
767If this is the case for your system, you may need to explicitly specify
768the path to the pod docs for the invoking script using something
769similar to the following:
770
771    pod2usage(-exitval => 2, -input => "/path/to/your/pod/docs");
772
773In the pathological case that a script is called via a relative path
774I<and> the script itself changes the current working directory
775(see L<perlfunc/chdir>) I<before> calling pod2usage, Pod::Usage will
776fail even on robust platforms. Don't do that. Or use L<FindBin> to locate
777the script:
778
779    use FindBin;
780    pod2usage(-input => $FindBin::Bin . "/" . $FindBin::Script);
781
782=head1 AUTHOR
783
784Please report bugs using L<http://rt.cpan.org>.
785
786Marek Rouchal E<lt>marekr@cpan.orgE<gt>
787
788Brad Appleton E<lt>bradapp@enteract.comE<gt>
789
790Based on code for B<Pod::Text::pod2text()> written by
791Tom Christiansen E<lt>tchrist@mox.perl.comE<gt>
792
793=head1 ACKNOWLEDGMENTS
794
795rjbs for refactoring Pod::Usage to not use Pod::Parser any more.
796
797Steven McDougall E<lt>swmcd@world.std.comE<gt> for his help and patience
798with re-writing this manpage.
799
800=head1 SEE ALSO
801
802B<Pod::Usage> is now a standalone distribution, depending on
803L<Pod::Text> which in turn depends on L<Pod::Simple>.
804
805L<Pod::Perldoc>, L<Getopt::Long>, L<Pod::Find>, L<FindBin>,
806L<Pod::Text>, L<Pod::Text::Termcap>, L<Pod::Simple>
807
808=cut
809
810