perldoc - Look up Perl documentation in Pod format.
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.
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.
- -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.
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.
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.
Up to 3.14_05, the switch -v was used to produce verbose messages of
perldoc operation, which is now enabled by -D.
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.