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perlpod (1)


perlpod - the Plain Old Documentation format


Please see following description for synopsis


Perl Programmers Reference Guide                       PERLPOD(1)

     perlpod - the Plain Old Documentation format

     Pod is a simple-to-use markup language used for writing
     documentation for Perl, Perl programs, and Perl modules.

     Translators are available for converting Pod to various
     formats like plain text, HTML, man pages, and more.

     Pod markup consists of three basic kinds of paragraphs:
     ordinary, verbatim, and command.

  Ordinary Paragraph
     Most paragraphs in your documentation will be ordinary
     blocks of text, like this one.  You can simply type in your
     text without any markup whatsoever, and with just a blank
     line before and after.  When it gets formatted, it will
     undergo minimal formatting, like being rewrapped, probably
     put into a proportionally spaced font, and maybe even

     You can use formatting codes in ordinary paragraphs, for
     bold, italic, "code-style", hyperlinks, and more.  Such
     codes are explained in the "Formatting Codes" section,

  Verbatim Paragraph
     Verbatim paragraphs are usually used for presenting a
     codeblock or other text which does not require any special
     parsing or formatting, and which shouldn't be wrapped.

     A verbatim paragraph is distinguished by having its first
     character be a space or a tab.  (And commonly, all its lines
     begin with spaces and/or tabs.)  It should be reproduced
     exactly, with tabs assumed to be on 8-column boundaries.
     There are no special formatting codes, so you can't
     italicize or anything like that.  A \ means \, and nothing

  Command Paragraph
     A command paragraph is used for special treatment of whole
     chunks of text, usually as headings or parts of lists.

     All command paragraphs (which are typically only one line
     long) start with "=", followed by an identifier, followed by
     arbitrary text that the command can use however it pleases.
     Currently recognized commands are

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Perl Programmers Reference Guide                       PERLPOD(1)

         =head1 Heading Text
         =head2 Heading Text
         =head3 Heading Text
         =head4 Heading Text
         =over indentlevel
         =item stuff
         =begin format
         =end format
         =for format text...
         =encoding type

     To explain them each in detail:

     "=head1 Heading Text"
     "=head2 Heading Text"
     "=head3 Heading Text"
     "=head4 Heading Text"
         Head1 through head4 produce headings, head1 being the
         highest level.  The text in the rest of this paragraph
         is the content of the heading.  For example:

           =head2 Object Attributes

         The text "Object Attributes" comprises the heading
         there.  (Note that head3 and head4 are recent additions,
         not supported in older Pod translators.)  The text in
         these heading commands can use formatting codes, as seen

           =head2 Possible Values for C<$/>

         Such commands are explained in the "Formatting Codes"
         section, below.

     "=over indentlevel"
     "=item stuff..."
         Item, over, and back require a little more explanation:
         "=over" starts a region specifically for the generation
         of a list using "=item" commands, or for indenting
         (groups of) normal paragraphs.  At the end of your list,
         use "=back" to end it.  The indentlevel option to
         "=over" indicates how far over to indent, generally in
         ems (where one em is the width of an "M" in the
         document's base font) or roughly comparable units; if
         there is no indentlevel option, it defaults to four.
         (And some formatters may just ignore whatever
         indentlevel you provide.)  In the stuff in "=item
         stuff...", you may use formatting codes, as seen here:

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           =item Using C<$|> to Control Buffering

         Such commands are explained in the "Formatting Codes"
         section, below.

         Note also that there are some basic rules to using
         "=over" ...  "=back" regions:

         o   Don't use "=item"s outside of an "=over" ... "=back"

         o   The first thing after the "=over" command should be
             an "=item", unless there aren't going to be any
             items at all in this "=over" ... "=back" region.

         o   Don't put "=headn" commands inside an "=over" ...
             "=back" region.

         o   And perhaps most importantly, keep the items
             consistent: either use "=item *" for all of them, to
             produce bullets; or use "=item 1.", "=item 2.",
             etc., to produce numbered lists; or use "=item foo",
             "=item bar", etc.--namely, things that look nothing
             like bullets or numbers.

             If you start with bullets or numbers, stick with
             them, as formatters use the first "=item" type to
             decide how to format the list.

         To end a Pod block, use a blank line, then a line
         beginning with "=cut", and a blank line after it.  This
         lets Perl (and the Pod formatter) know that this is
         where Perl code is resuming.  (The blank line before the
         "=cut" is not technically necessary, but many older Pod
         processors require it.)

         The "=pod" command by itself doesn't do much of
         anything, but it signals to Perl (and Pod formatters)
         that a Pod block starts here.  A Pod block starts with
         any command paragraph, so a "=pod" command is usually
         used just when you want to start a Pod block with an
         ordinary paragraph or a verbatim paragraph.  For

           =item stuff()

           This function does stuff.


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           sub stuff {


           Remember to check its return value, as in:

             stuff() || die "Couldn't do stuff!";


     "=begin formatname"
     "=end formatname"
     "=for formatname text..."
         For, begin, and end will let you have regions of
         text/code/data that are not generally interpreted as
         normal Pod text, but are passed directly to particular
         formatters, or are otherwise special.  A formatter that
         can use that format will use the region, otherwise it
         will be completely ignored.

         A command "=begin formatname", some paragraphs, and a
         command "=end formatname", mean that the text/data in
         between is meant for formatters that understand the
         special format called formatname.  For example,

           =begin html

           <hr> <img src="thang.png">
           <p> This is a raw HTML paragraph </p>

           =end html

         The command "=for formatname text..."  specifies that
         the remainder of just this paragraph (starting right
         after formatname) is in that special format.

           =for html <hr> <img src="thang.png">
           <p> This is a raw HTML paragraph </p>

         This means the same thing as the above "=begin html" ...
         "=end html" region.

         That is, with "=for", you can have only one paragraph's
         worth of text (i.e., the text in "=foo targetname
         text..."), but with "=begin targetname" ... "=end
         targetname", you can have any amount of stuff inbetween.
         (Note that there still must be a blank line after the
         "=begin" command and a blank line before the "=end"

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         Here are some examples of how to use these:

           =begin html

           <br>Figure 1.<br><IMG SRC="figure1.png"><br>

           =end html

           =begin text

             |  foo        |
             |        bar  |

           ^^^^ Figure 1. ^^^^

           =end text

         Some format names that formatters currently are known to
         accept include "roff", "man", "latex", "tex", "text",
         and "html".  (Some formatters will treat some of these
         as synonyms.)

         A format name of "comment" is common for just making
         notes (presumably to yourself) that won't appear in any
         formatted version of the Pod document:

           =for comment
           Make sure that all the available options are documented!

         Some formatnames will require a leading colon (as in
         "=for :formatname", or "=begin :formatname" ... "=end
         :formatname"), to signal that the text is not raw data,
         but instead is Pod text (i.e., possibly containing
         formatting codes) that's just not for normal formatting
         (e.g., may not be a normal-use paragraph, but might be
         for formatting as a footnote).

     "=encoding encodingname"
         This command is used for declaring the encoding of a
         document.  Most users won't need this; but if your
         encoding isn't US-ASCII or Latin-1, then put a
         "=encoding encodingname" command early in the document
         so that pod formatters will know how to decode the
         document.  For encodingname, use a name recognized by
         the Encode::Supported module.  Examples:

           =encoding utf8

           =encoding koi8-r

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           =encoding ShiftJIS

           =encoding big5

     "=encoding" affects the whole document, and must occur only

     And don't forget, when using any other command, that the
     command lasts up until the end of its paragraph, not its
     line.  So in the examples below, you can see that every
     command needs the blank line after it, to end its paragraph.

     Some examples of lists include:


       =item *

       First item

       =item *

       Second item



       =item Foo()

       Description of Foo function

       =item Bar()

       Description of Bar function


  Formatting Codes
     In ordinary paragraphs and in some command paragraphs,
     various formatting codes (a.k.a. "interior sequences") can
     be used:

     "I<text>" -- italic text
         Used for emphasis (""be I<careful!>"") and parameters
         (""redo I<LABEL>"")

     "B<text>" -- bold text
         Used for switches (""perl's B<-n> switch""), programs
         (""some systems provide a B<chfn> for that""), emphasis
         (""be B<careful!>""), and so on (""and that feature is
         known as B<autovivification>"").

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     "C<code>" -- code text
         Renders code in a typewriter font, or gives some other
         indication that this represents program text
         (""C<gmtime($^T)>"") or some other form of computerese

     "L<name>" -- a hyperlink
         There are various syntaxes, listed below.  In the
         syntaxes given, "text", "name", and "section" cannot
         contain the characters '/' and '|'; and any '<' or '>'
         should be matched.

         o   "L<name>"

             Link to a Perl manual page (e.g., "L<Net::Ping>").
             Note that "name" should not contain spaces.  This
             syntax is also occasionally used for references to
             Unix man pages, as in "L<crontab(5)>".

         o   "L<name/"sec">" or "L<name/sec>"

             Link to a section in other manual page.  E.g.,
             "L<perlsyn/"For Loops">"

         o   "L</"sec">" or "L</sec>"

             Link to a section in this manual page.  E.g.,
             "L</"Object Methods">"

         A section is started by the named heading or item.  For
         example, "L<perlvar/$.>" or "L<perlvar/"$.">" both link
         to the section started by ""=item $."" in perlvar.  And
         "L<perlsyn/For Loops>" or "L<perlsyn/"For Loops">" both
         link to the section started by ""=head2 For Loops"" in

         To control what text is used for display, you use
         ""L<text|...>"", as in:

         o   "L<text|name>"

             Link this text to that manual page.  E.g., "L<Perl
             Error Messages|perldiag>"

         o   "L<text|name/"sec">" or "L<text|name/sec>"

             Link this text to that section in that manual page.
             E.g., "L<postfix "if"|perlsyn/"Statement

         o   "L<text|/"sec">" or "L<text|/sec>" or

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             Link this text to that section in this manual page.
             E.g., "L<the various attributes|/"Member Data">"

         Or you can link to a web page:

         o   "L<scheme:...>"


             Links to an absolute URL.  For example,
             "L<>" or "L<The Perl Home

     "E<escape>" -- a character escape
         Very similar to HTML/XML "&foo;" "entity references":

         o   "E<lt>" -- a literal < (less than)

         o   "E<gt>" -- a literal > (greater than)

         o   "E<verbar>" -- a literal | (vertical bar)

         o   "E<sol>" = a literal / (solidus)

             The above four are optional except in other
             formatting codes, notably "L<...>", and when
             preceded by a capital letter.

         o   "E<htmlname>"

             Some non-numeric HTML entity name, such as
             "E<eacute>", meaning the same thing as "&eacute;" in
             HTML -- i.e., a lowercase e with an acute (/-shaped)

         o   "E<number>"

             The ASCII/Latin-1/Unicode character with that
             number.  A leading "0x" means that number is hex, as
             in "E<0x201E>".  A leading "0" means that number is
             octal, as in "E<075>".  Otherwise number is
             interpreted as being in decimal, as in "E<181>".

             Note that older Pod formatters might not recognize
             octal or hex numeric escapes, and that many
             formatters cannot reliably render characters above
             255.  (Some formatters may even have to use
             compromised renderings of Latin-1 characters, like
             rendering "E<eacute>" as just a plain "e".)

     "F<filename>" -- used for filenames
         Typically displayed in italics.  Example: ""F<.cshrc>""

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     "S<text>" -- text contains non-breaking spaces
         This means that the words in text should not be broken
         across lines.  Example: "S<$x ? $y : $z>".

     "X<topic name>" -- an index entry
         This is ignored by most formatters, but some may use it
         for building indexes.  It always renders as empty-
         string.  Example: "X<absolutizing relative URLs>"

     "Z<>" -- a null (zero-effect) formatting code
         This is rarely used.  It's one way to get around using
         an E<...> code sometimes.  For example, instead of
         ""NE<lt>3"" (for "N<3") you could write ""NZ<><3"" (the
         "Z<>" breaks up the "N" and the "<" so they can't be
         considered the part of a (fictitious) "N<...>" code.

     Most of the time, you will need only a single set of angle
     brackets to delimit the beginning and end of formatting
     codes.  However, sometimes you will want to put a real right
     angle bracket (a greater-than sign, '>') inside of a
     formatting code.  This is particularly common when using a
     formatting code to provide a different font-type for a
     snippet of code.  As with all things in Perl, there is more
     than one way to do it.  One way is to simply escape the
     closing bracket using an "E" code:

         C<$a E<lt>=E<gt> $b>

     This will produce: ""$a <=> $b""

     A more readable, and perhaps more "plain" way is to use an
     alternate set of delimiters that doesn't require a single
     ">" to be escaped.  Doubled angle brackets ("<<" and ">>")
     may be used if and only if there is whitespace right after
     the opening delimiter and whitespace right before the
     closing delimiter!  For example, the following will do the

         C<< $a <=> $b >>

     In fact, you can use as many repeated angle-brackets as you
     like so long as you have the same number of them in the
     opening and closing delimiters, and make sure that
     whitespace immediately follows the last '<' of the opening
     delimiter, and immediately precedes the first '>' of the
     closing delimiter.  (The whitespace is ignored.)  So the
     following will also work:

         C<<< $a <=> $b >>>
         C<<<<  $a <=> $b     >>>>

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     And they all mean exactly the same as this:

         C<$a E<lt>=E<gt> $b>

     The multiple-bracket form does not affect the interpretation
     of the contents of the formatting code, only how it must
     end.  That means that the examples above are also exactly
     the same as this:

         C<< $a E<lt>=E<gt> $b >>

     As a further example, this means that if you wanted to put
     these bits of code in "C" (code) style:

         open(X, ">>thing.dat") || die $!

     you could do it like so:

         C<<< open(X, ">>thing.dat") || die $! >>>
         C<< $foo->bar(); >>

     which is presumably easier to read than the old way:

         C<open(X, "E<gt>E<gt>thing.dat") || die $!>

     This is currently supported by pod2text (Pod::Text), pod2man
     (Pod::Man), and any other pod2xxx or Pod::Xxxx translators
     that use Pod::Parser 1.093 or later, or Pod::Tree 1.02 or

  The Intent
     The intent is simplicity of use, not power of expression.
     Paragraphs look like paragraphs (block format), so that they
     stand out visually, and so that I could run them through
     "fmt" easily to reformat them (that's F7 in my version of
     vi, or Esc Q in my version of emacs).  I wanted the
     translator to always leave the "'" and "`" and """ quotes
     alone, in verbatim mode, so I could slurp in a working
     program, shift it over four spaces, and have it print out,
     er, verbatim.  And presumably in a monospace font.

     The Pod format is not necessarily sufficient for writing a
     book.  Pod is just meant to be an idiot-proof common source
     for nroff, HTML, TeX, and other markup languages, as used
     for online documentation.  Translators exist for pod2text,
     pod2html, pod2man (that's for nroff(1) and troff(1)),
     pod2latex, and pod2fm.  Various others are available in

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  Embedding Pods in Perl Modules
     You can embed Pod documentation in your Perl modules and
     scripts.  Start your documentation with an empty line, a
     "=head1" command at the beginning, and end it with a "=cut"
     command and an empty line.  Perl will ignore the Pod text.
     See any of the supplied library modules for examples.  If
     you're going to put your Pod at the end of the file, and
     you're using an __END__ or __DATA__ cut mark, make sure to
     put an empty line there before the first Pod command.


       =head1 NAME

       Time::Local - efficiently compute time from local and GMT time

     Without that empty line before the "=head1", many
     translators wouldn't have recognized the "=head1" as
     starting a Pod block.

  Hints for Writing Pod

         The podchecker command is provided for checking Pod
         syntax for errors and warnings.  For example, it checks
         for completely blank lines in Pod blocks and for unknown
         commands and formatting codes.  You should still also
         pass your document through one or more translators and
         proofread the result, or print out the result and
         proofread that.  Some of the problems found may be bugs
         in the translators, which you may or may not wish to
         work around.

     o   If you're more familiar with writing in HTML than with
         writing in Pod, you can try your hand at writing
         documentation in simple HTML, and converting it to Pod
         with the experimental Pod::HTML2Pod module, (available
         in CPAN), and looking at the resulting code.  The
         experimental Pod::PXML module in CPAN might also be

     o   Many older Pod translators require the lines before
         every Pod command and after every Pod command (including
         "=cut"!) to be a blank line.  Having something like

          # - - - - - - - - - - - -
          =item $firecracker->boom()

          This noisily detonates the firecracker object.
          sub boom {

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         ...will make such Pod translators completely fail to see
         the Pod block at all.

         Instead, have it like this:

          # - - - - - - - - - - - -

          =item $firecracker->boom()

          This noisily detonates the firecracker object.


          sub boom {

     o   Some older Pod translators require paragraphs (including
         command paragraphs like "=head2 Functions") to be
         separated by completely empty lines.  If you have an
         apparently empty line with some spaces on it, this might
         not count as a separator for those translators, and that
         could cause odd formatting.

     o   Older translators might add wording around an L<> link,
         so that "L<Foo::Bar>" may become "the Foo::Bar manpage",
         for example.  So you shouldn't write things like "the
         L<foo> documentation", if you want the translated
         document to read sensibly.  Instead, write "the
         L<Foo::Bar|Foo::Bar> documentation" or "L<the Foo::Bar
         documentation|Foo::Bar>", to control how the link comes

     o   Going past the 70th column in a verbatim block might be
         ungracefully wrapped by some formatters.

     See attributes(5) for descriptions of the following

     |Availability   | runtime/perl-512 |
     |Stability      | Uncommitted      |
     perlpodspec, "PODs: Embedded Documentation" in perlsyn,
     perlnewmod, perldoc, pod2html, pod2man, podchecker.

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     Larry Wall, Sean M. Burke

     This software was built from source available at  The original
     community source was downloaded from

     Further information about this software can be found on the
     open source community website at

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