Write Perl Documentation That Survives the Pod Formatter

You will finish with a small Perl Pod man page that has the expected structure, readable examples, and a local syntax check. This is a writing and review task, not a command with switches: perldocstyle is the name of a man page supplied by the perl-doc package.

Allow about 20 minutes for a short page, plus however long it takes to test the behaviour you are documenting. The examples here use Perl 5.38.2 from Ubuntu's perl-doc package, installed locally as version 5.38.2-3.2ubuntu0.6. The style principles are useful elsewhere, but the installed man page is the authority for this machine.

Checkpoint: confirm the guide and tools

1. Read the installed guide through perldoc:

   perldoc -l perldocstyle
   perldoc perldocstyle | less

   The first command should print /usr/share/perl/5.38/pod/perldocstyle.pod. The packaged man page is also available with man perldocstyle. There is no separate perldocstyle executable to run.

2. Check that the Pod validator is installed:

   command -v podchecker

   On this system it is /usr/bin/podchecker. If it is missing, install the distribution package that supplies your Perl documentation tools before continuing. That is an administrative change, so use your normal privileged package workflow and review the package name for your distribution.

Step 1: start with the document skeleton

Create a file named after the subject, such as lib/Inventory/Report.pod or pod/perlwarehouse.pod. Keep the source in version control. For a core-style standalone page, begin with UTF-8 encoding, then a literal NAME heading and one short name-and-purpose paragraph.

=encoding utf8

=head1 NAME

perlwarehouse - read warehouse stock records

=head1 DESCRIPTION

This page explains the file format and the Perl interface used to read
warehouse stock records. It is intended for maintainers who already know
basic Perl syntax.

=head1 SYNOPSIS

    use Warehouse::Report;

    my $report = Warehouse::Report->new(path => $path);
    print $report->total_items, "\n";

=head1 FILE FORMAT

The input is one UTF-8 record per line. The first field is the item code.

=head1 SEE ALSO

L<perlpod>, L<perlpodstyle>

=cut

Use DESCRIPTION to state what the page covers and what it assumes. A reference page can put a brief SYNOPSIS before the description. Do not turn the synopsis into an exhaustive catalogue: show a few common, best-practice uses, then explain them in the sections that follow.

Step 2: make the Pod easy to navigate

Choose headings for the reader's route through the subject. Use additional top-level headings in capitals when the topic needs them, and put narrower subjects below them. A page about a module might use METHODS, ERROR HANDLING, and SEE ALSO; a page about a language feature might need different names. The guide does not require a fixed list beyond the familiar man-page shape.

Keep each source line to 72 characters or fewer. This is a rule for the Pod source, not a promise that every formatter will display exactly 72 columns. Short lines make reviews, terminal output, and later edits less surprising. Break up a long block with meaningful subsections when a reader could reasonably stop and resume later.

Use Pod's inline markup for code and names. Write C<open> for a function name, C<$path> for a variable, and L<perlpod> for a cross-reference. A link can have separate visible text and a target, for example L<Pod syntax|perlpod>. Link to a relevant man page or primary web page from SEE ALSO; a link does not replace the formatting needed to identify the thing in the sentence.

Step 3: write examples that explain themselves

Keep a code block as small as possible while still showing the idea. Follow the layout rules of perlstyle, and use names that describe their jobs. $warehouse_report tells the reader more than $foo. Comments are useful when they clarify a non-obvious line, but they should not compensate for an example that is too large.

Give function arguments meaningful names and use the right form for the object being documented. If the page describes a generic scalar, say so; if it expects a file path, call the argument PATH or $path consistently. Put literal angle brackets in Pod markup where required rather than relying on a formatter to guess what code means.

Use straight quotation marks. The source guide permits UTF-8, but typographic quotes still make source maintenance and terminal reading needlessly awkward. In Pod, render an em dash as two hyphens if one is genuinely needed. Prefer a full stop or a new sentence when that is clearer.

Step 4: check the file before review

Run the syntax checker against the actual file, not a pasted fragment:

podchecker lib/Inventory/Report.pod

A clean file ends with output similar to lib/Inventory/Report.pod pod syntax OK and a zero exit status. Confirm both the rendered view and the status:

perldoc lib/Inventory/Report.pod | less
podchecker lib/Inventory/Report.pod
test $? -eq 0 && echo "Pod check passed"

podchecker tests Pod syntax, not whether your API claims are true. Exercise the documented program separately, and check that names, defaults, errors, and version notes match the implementation. If an example changes files, use a temporary directory while testing. Do not run an unreviewed example as root: documentation review is not a reason to grant extra privileges.

Common traps to remove during review

• Missing identity: a page without the NAME entry is harder for formatters and readers to classify.
• Unstated audience: say whether the reader needs basic Perl, a particular module, or knowledge of an internal format.
• Example overload: replace a long program with one focused example and explain the important part nearby.
• Vague names: replace throwaway variables with names that show relationships and purpose.
• Stale history: document current behaviour first. Mention older behaviour only when a maintainer is likely to meet it.
• Hidden cross-references: finish with useful SEE ALSO links and make their visible text describe the destination.

For a standalone core page, extra copyright or licence sections are normally unnecessary because the source repository supplies those terms. An AUTHOR or CONTRIBUTORS section is optional when credit helps. Module documentation follows its own packaging and authorship conventions, so check perlpodstyle as well as this guide before treating the skeleton as universal.

Done means

• The file begins with =encoding utf8 and a clear NAME entry.
• The audience, purpose, common usage, and relevant caveats are explicit.
• Headings, links, inline markup, examples, and line wrapping follow the Pod guidance.
• podchecker FILE reports success, and perldoc FILE is readable.
• The documented behaviour has been tested independently of the markup check.