PERLDOC(1) Perl Programmers Reference Guide PERLDOC(1)
NAME
perldoc - Look up Perl documentation in Pod format.
SYNOPSIS
perldoc [-h] [-D] [-t] [-u] [-m] [-l] [-U] [-F]
[-i] [-V] [-T] [-r]
[-d destination_file]
[-o formatname]
[-M FormatterClassName]
[-w formatteroption:value]
[-n nroff-replacement]
[-X]
[-L language_code]
PageName|ModuleName|ProgramName|URL
Examples:
perldoc -f BuiltinFunction
perldoc -L it -f BuiltinFunction
perldoc -q FAQ Keyword
perldoc -L fr -q FAQ Keyword
perldoc -v PerlVariable
perldoc -a PerlAPI
See below for more description of the switches.
DESCRIPTION
perldoc looks up documentation in .pod format that is embedded in the
perl installation tree or in a perl script, and displays it using a
variety of formatters. This is primarily used for the documentation
for the perl library modules.
Your system may also have man pages installed for those modules, in
which case you can probably just use the man(1) command.
If you are looking for a table of contents to the Perl library modules
documentation, see the perltoc page.
OPTIONS
-h Prints out a brief help message.
-D Describes search for the item in detail.
-t Display docs using plain text converter, instead of nroff. This
may be faster, but it probably won't look as nice.
-u Skip the real Pod formatting, and just show the raw Pod source
(Unformatted)
-m module
Display the entire module: both code and unformatted pod
documentation. This may be useful if the docs don't explain a
function in the detail you need, and you'd like to inspect the
code directly; perldoc will find the file for you and simply hand
it off for display.
-l Display only the file name of the module found.
-U When running as the superuser, don't attempt drop privileges for
security. This option is implied with -F.
NOTE: Please see the heading SECURITY below for more information.
-F Consider arguments as file names; no search in directories will be
performed. Implies -U if run as the superuser.
-f perlfunc
The -f option followed by the name of a perl built-in function
will extract the documentation of this function from perlfunc.
Example:
perldoc -f sprintf
-q perlfaq-search-regexp
The -q option takes a regular expression as an argument. It will
search the question headings in perlfaq[1-9] and print the entries
matching the regular expression.
Example:
perldoc -q shuffle
-a perlapifunc
The -a option followed by the name of a perl api function will
extract the documentation of this function from perlapi.
Example:
perldoc -a newHV
-v perlvar
The -v option followed by the name of a Perl predefined variable
will extract the documentation of this variable from perlvar.
Examples:
perldoc -v '$"'
perldoc -v @+
perldoc -v DATA
-T This specifies that the output is not to be sent to a pager, but
is to be sent directly to STDOUT.
-d destination-filename
This specifies that the output is to be sent neither to a pager
nor to STDOUT, but is to be saved to the specified filename.
Example: "perldoc -oLaTeX -dtextwrapdocs.tex Text::Wrap"
-o output-formatname
This specifies that you want Perldoc to try using a Pod-formatting
class for the output format that you specify. For example:
"-oman". This is actually just a wrapper around the "-M" switch;
using "-oformatname" just looks for a loadable class by adding
that format name (with different capitalizations) to the end of
different classname prefixes.
For example, "-oLaTeX" currently tries all of the following
classes: Pod::Perldoc::ToLaTeX Pod::Perldoc::Tolatex
Pod::Perldoc::ToLatex Pod::Perldoc::ToLATEX Pod::Simple::LaTeX
Pod::Simple::latex Pod::Simple::Latex Pod::Simple::LATEX
Pod::LaTeX Pod::latex Pod::Latex Pod::LATEX.
-M module-name
This specifies the module that you want to try using for
formatting the pod. The class must at least provide a
"parse_from_file" method. For example: "perldoc
-MPod::Perldoc::ToChecker".
You can specify several classes to try by joining them with commas
or semicolons, as in "-MTk::SuperPod;Tk::Pod".
-w option:value or -w option
This specifies an option to call the formatter with. For example,
"-w textsize:15" will call "$formatter->textsize(15)" on the
formatter object before it is used to format the object. For this
to be valid, the formatter class must provide such a method, and
the value you pass should be valid. (So if "textsize" expects an
integer, and you do "-w textsize:big", expect trouble.)
You can use "-w optionname" (without a value) as shorthand for "-w
optionname:TRUE". This is presumably useful in cases of on/off
features like: "-w page_numbering".
You can use an "=" instead of the ":", as in: "-w textsize=15".
This might be more (or less) convenient, depending on what shell
you use.
-X Use an index if it is present. The -X option looks for an entry
whose basename matches the name given on the command line in the
file "$Config{archlib}/pod.idx". The pod.idx file should contain
fully qualified filenames, one per line.
-L language_code
This allows one to specify the language code for the desired
language translation. If the "POD2::<language_code>" package isn't
installed in your system, the switch is ignored. All available
translation packages are to be found under the "POD2::" namespace.
See POD2::IT (or POD2::FR) to see how to create new localized
"POD2::*" documentation packages and integrate them into
Pod::Perldoc.
PageName|ModuleName|ProgramName|URL
The item you want to look up. Nested modules (such as
"File::Basename") are specified either as "File::Basename" or
"File/Basename". You may also give a descriptive name of a page,
such as "perlfunc". For URLs, HTTP and HTTPS are the only kind
currently supported.
For simple names like 'foo', when the normal search fails to find
a matching page, a search with the "perl" prefix is tried as well.
So "perldoc intro" is enough to find/render "perlintro.pod".
-n some-formatter
Specify replacement for groff
-r Recursive search.
-i Ignore case.
-V Displays the version of perldoc you're running.
SECURITY
Because perldoc does not run properly tainted, and is known to have
security issues, when run as the superuser it will attempt to drop
privileges by setting the effective and real IDs to nobody's or
nouser's account, or -2 if unavailable. If it cannot relinquish its
privileges, it will not run.
See the "-U" option if you do not want this behavior but beware that
there are significant security risks if you choose to use "-U".
Since 3.26, using "-F" as the superuser also implies "-U" as opening
most files and traversing directories requires privileges that are
above the nobody/nogroup level.
ENVIRONMENT
Any switches in the "PERLDOC" environment variable will be used before
the command line arguments.
Useful values for "PERLDOC" include "-oterm", "-otext", "-ortf",
"-oxml", and so on, depending on what modules you have on hand; or the
formatter class may be specified exactly with "-MPod::Perldoc::ToTerm"
or the like.
"perldoc" also searches directories specified by the "PERL5LIB" (or
"PERLLIB" if "PERL5LIB" is not defined) and "PATH" environment
variables. (The latter is so that embedded pods for executables, such
as "perldoc" itself, are available.)
In directories where either "Makefile.PL" or "Build.PL" exist,
"perldoc" will add "." and "lib" first to its search path, and as long
as you're not the superuser will add "blib" too. This is really
helpful if you're working inside of a build directory and want to read
through the docs even if you have a version of a module previously
installed.
"perldoc" will use, in order of preference, the pager defined in
"PERLDOC_PAGER", "MANPAGER", or "PAGER" before trying to find a pager
on its own. ("MANPAGER" is not used if "perldoc" was told to display
plain text or unformatted pod.)
When using perldoc in it's "-m" mode (display module source code),
"perldoc" will attempt to use the pager set in "PERLDOC_SRC_PAGER". A
useful setting for this command is your favorite editor as in
"/usr/bin/nano". (Don't judge me.)
One useful value for "PERLDOC_PAGER" is "less -+C -E".
Having PERLDOCDEBUG set to a positive integer will make perldoc emit
even more descriptive output than the "-D" switch does; the higher the
number, the more it emits.
CHANGES
Up to 3.14_05, the switch -v was used to produce verbose messages of
perldoc operation, which is now enabled by -D.
SEE ALSO
perlpod, Pod::Perldoc
AUTHOR
Current maintainer: Mark Allen "<mallen@cpan.org>"
Past contributors are: brian d foy "<bdfoy@cpan.org>" Adriano R.
Ferreira "<ferreira@cpan.org>", Sean M. Burke "<sburke@cpan.org>",
Kenneth Albanowski "<kjahds@kjahds.com>", Andy Dougherty
"<doughera@lafcol.lafayette.edu>", and many others.
perl v5.30.3 2020-06-07 PERLDOC(1)