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[perl5.git] / pod / perlfaq2.pod

=head1 NAME

perlfaq2 - Obtaining and Learning about Perl

=head1 DESCRIPTION

This section of the FAQ answers questions about where to find
source and documentation for Perl, support, and
related matters.

=head2 What machines support perl? Where do I get it?

The standard release of perl (the one maintained by the perl
development team) is distributed only in source code form. You
can find the latest releases at http://www.cpan.org/src/README.html .

Perl builds and runs on a bewildering number of platforms. Virtually
all known and current Unix derivatives are supported (perl's native
platform), as are other systems like VMS, DOS, OS/2, Windows,
QNX, BeOS, OS X, MPE/iX and the Amiga.

Binary distributions for some proprietary platforms can be found
http://www.cpan.org/ports/ directory. Because these are not part of
the standard distribution, they may and in fact do differ from the
base perl port in a variety of ways. You'll have to check their
respective release notes to see just what the differences are. These
differences can be either positive (e.g. extensions for the features
of the particular platform that are not supported in the source
release of perl) or negative (e.g. might be based upon a less current
source release of perl).

=head2 How can I get a binary version of perl?

(contributed by brian d foy)

ActiveState: Windows, Linux, Mac OS X, Solaris, AIX and HP-UX

        http://www.activestate.com/

Sunfreeware.com: Solaris 2.5 to Solaris 10 (SPARC and x86)

        http://www.sunfreeware.com/

Strawberry Perl: Windows, Perl 5.8.8 and 5.10.0

        http://www.strawberryperl.com

IndigoPerl: Windows

        http://indigostar.com/

=head2 I don't have a C compiler. How can I build my own Perl interpreter?

Since you don't have a C compiler, you're doomed and your vendor
should be sacrificed to the Sun gods. But that doesn't help you.

What you need to do is get a binary version of C<gcc> for your system
first. Consult the Usenet FAQs for your operating system for
information on where to get such a binary version.

You might look around the net for a pre-built binary of Perl (or a
C compiler!) that meets your needs, though:

For Windows, Vanilla Perl ( http://vanillaperl.com/ ) and Strawberry Perl
( http://strawberryperl.com/ ) come with a
bundled C compiler. ActivePerl is a pre-compiled version of Perl
ready-to-use.

For Sun systems, SunFreeware.com provides binaries of most popular
applications, including compilers and Perl.

=head2 I copied the perl binary from one machine to another, but scripts don't work.

That's probably because you forgot libraries, or library paths differ.
You really should build the whole distribution on the machine it will
eventually live on, and then type C<make install>. Most other
approaches are doomed to failure.

One simple way to check that things are in the right place is to print out
the hard-coded C<@INC> that perl looks through for libraries:

    % perl -le 'print for @INC'

If this command lists any paths that don't exist on your system, then you
may need to move the appropriate libraries to these locations, or create
symbolic links, aliases, or shortcuts appropriately. C<@INC> is also printed as
part of the output of

    % perl -V

You might also want to check out
L<perlfaq8/"How do I keep my own module/library directory?">.

=head2 I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work?

Read the F<INSTALL> file, which is part of the source distribution.
It describes in detail how to cope with most idiosyncrasies that the
C<Configure> script can't work around for any given system or
architecture.

=head2 What modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean?

CPAN stands for Comprehensive Perl Archive Network, a multi-gigabyte
archive replicated on hundreds of machines all over the world. CPAN
contains source code, non-native ports, documentation, scripts, and
many third-party modules and extensions, designed for everything from
commercial database interfaces to keyboard/screen control to web
walking and CGI scripts. The master web site for CPAN is
http://www.cpan.org/ and there is the CPAN Multiplexer at
http://www.cpan.org/CPAN.html which will choose a mirror near you via
DNS. See http://www.perl.com/CPAN (without a slash at the end) for
how this process works. Also, http://mirror.cpan.org/ has a nice
interface to the http://www.cpan.org/MIRRORED.BY mirror directory.

See the CPAN FAQ at http://www.cpan.org/misc/cpan-faq.html for answers
to the most frequently asked questions about CPAN including how to
become a mirror.

C<CPAN/path/...> is a naming convention for files available on CPAN
sites. CPAN indicates the base directory of a CPAN mirror, and the
rest of the path is the path from that directory to the file. For
instance, if you're using ftp://ftp.funet.fi/pub/languages/perl/CPAN
as your CPAN site, the file C<CPAN/misc/japh> is downloadable as
ftp://ftp.funet.fi/pub/languages/perl/CPAN/misc/japh .

Considering that, as of 2006, there are over ten thousand existing
modules in the archive, one probably exists to do nearly anything you
can think of. Current categories under C<CPAN/modules/by-category/>
include Perl core modules; development support; operating system
interfaces; networking, devices, and interprocess communication; data
type utilities; database interfaces; user interfaces; interfaces to
other languages; filenames, file systems, and file locking;
internationalization and locale; world wide web support; server and
daemon utilities; archiving and compression; image manipulation; mail
and news; control flow utilities; filehandle and I/O; Microsoft
Windows modules; and miscellaneous modules.

See http://www.cpan.org/modules/00modlist.long.html or
http://search.cpan.org/ for a more complete list of modules by
category.

CPAN is a free service and is not affiliated with O'Reilly Media.

=head2 Is there an ISO or ANSI certified version of Perl?

Certainly not. Larry expects that he'll be certified before Perl is.

=head2 Where can I get information on Perl?

The complete Perl documentation is available with the Perl distribution.
If you have Perl installed locally, you probably have the documentation
installed as well: type C<man perl> if you're on a system resembling Unix.
This will lead you to other important man pages, including how to set your
C<$MANPATH>. If you're not on a Unix system, access to the documentation
will be different; for example, documentation might only be in HTML format. All
proper perl installations have fully-accessible documentation.

You might also try C<perldoc perl> in case your system doesn't
have a proper C<man> command, or it's been misinstalled. If that doesn't
work, try looking in C</usr/local/lib/perl5/pod> for documentation.

If all else fails, consult http://perldoc.perl.org/ which has the
complete documentation in HTML and PDF format.

Many good books have been written about Perl--see the section later in
L<perlfaq2> for more details.

Tutorial documents are included in current or upcoming Perl releases
include L<perltoot> for objects or L<perlboot> for a beginner's
approach to objects, L<perlopentut> for file opening semantics,
L<perlreftut> for managing references, L<perlretut> for regular
expressions, L<perlthrtut> for threads, L<perldebtut> for debugging,
and L<perlxstut> for linking C and Perl together. There may be more
by the time you read this. These URLs might also be useful:

    http://perldoc.perl.org/
    http://bookmarks.cpan.org/search.cgi?cat=Training%2FTutorials

=head2 What are the Perl newsgroups on Usenet? Where do I post questions?

Several groups devoted to the Perl language are on Usenet:

        comp.lang.perl.announce      Moderated announcement group
        comp.lang.perl.misc          High traffic general Perl discussion
        comp.lang.perl.moderated     Moderated discussion group
        comp.lang.perl.modules       Use and development of Perl modules
        comp.lang.perl.tk            Using Tk (and X) from Perl

Some years ago, comp.lang.perl was divided into those groups, and
comp.lang.perl itself officially removed. While that group may still
be found on some news servers, it is unwise to use it, because
postings there will not appear on news servers which honour the
official list of group names. Use comp.lang.perl.misc for topics
which do not have a more-appropriate specific group.

There is also a Usenet gateway to Perl mailing lists sponsored by
perl.org at nntp://nntp.perl.org , a web interface to the same lists
at http://nntp.perl.org/group/ and these lists are also available
under the C<perl.*> hierarchy at http://groups.google.com . Other
groups are listed at http://lists.perl.org/ ( also known as
http://lists.cpan.org/ ).

A nice place to ask questions is the PerlMonks site,
http://www.perlmonks.org/ , or the Perl Beginners mailing list
http://lists.perl.org/showlist.cgi?name=beginners .

Note that none of the above are supposed to write your code for you:
asking questions about particular problems or general advice is fine,
but asking someone to write your code for free is not very cool.

=head2 Where should I post source code?

You should post source code to whichever group is most appropriate, but
feel free to cross-post to comp.lang.perl.misc. If you want to cross-post
to alt.sources, please make sure it follows their posting standards,
including setting the Followup-To header line to NOT include alt.sources;
see their FAQ ( http://www.faqs.org/faqs/alt-sources-intro/ ) for details.

If you're just looking for software, first use Google
( http://www.google.com ), Google's Usenet search interface
( http://groups.google.com ), and CPAN Search ( http://search.cpan.org ).
This is faster and more productive than just posting a request.

=head2 Perl Books

There are many good books on Perl. See the L<perlbook> documentation or
( http://books.perl.org ).

=head2 Which magazines have Perl content?

I<The Perl Review> ( http://www.theperlreview.com ) focuses on Perl
almost completely (although it sometimes sneaks in an article about
another language). There's also I<$foo Magazin>, a german magazine
dedicated to Perl, at ( http://www.foo-magazin.de ).

The I<Perl-Zeitung> is a German-speaking magazine for Perl beginners
(see http://perl-zeitung.at.tf ).

Magazines that frequently carry quality articles on Perl include I<The
Perl Review> ( http://www.theperlreview.com ), I<Unix Review> (
http://www.unixreview.com/ ), I<Linux Magazine> (
http://www.linuxmagazine.com/ ), and Usenix's newsletter/magazine to
its members, I<login:> ( http://www.usenix.org/ ).

The Perl columns of Randal L. Schwartz are available on the web at
http://www.stonehenge.com/merlyn/WebTechniques/ ,
http://www.stonehenge.com/merlyn/UnixReview/ , and
http://www.stonehenge.com/merlyn/LinuxMag/ .

The first (and for a long time, only) periodical devoted to All Things
Perl, I<The Perl Journal> contains tutorials, demonstrations, case
studies, announcements, contests, and much more. I<TPJ> has columns
on web development, databases, Win32 Perl, graphical programming,
regular expressions, and networking, and sponsors the Obfuscated Perl
Contest and the Perl Poetry Contests. Beginning in November 2002, I<TPJ>
moved to a reader-supported monthly e-zine format in which subscribers
can download issues as PDF documents. In 2006, I<TPJ> merged with Dr.
Dobbs Journal (online edition). To read old I<TPJ> articles, see
http://www.ddj.com/ , brian d foy's index of online TPJ content
( http://www.perlmonks.org/index.pl?node_id=711609 ).

=head2 What mailing lists are there for Perl?

Most of the major modules (C<Tk>, C<CGI>, C<libwww-perl>) have their own
mailing lists. Consult the documentation that came with the module for
subscription information.

A comprehensive list of Perl related mailing lists can be found at:

        http://lists.perl.org/

=head2 Where are the archives for comp.lang.perl.misc?

The Google search engine now carries archived and searchable newsgroup
content.

http://groups.google.com/group/comp.lang.perl.misc/topics

If you have a question, you can be sure someone has already asked the
same question at some point on c.l.p.m. It requires some time and patience
to sift through all the content but often you will find the answer you
seek.

=head2 Where can I buy a commercial version of perl?

In a real sense, perl already I<is> commercial software: it has a license
that you can grab and carefully read to your manager. It is distributed
in releases and comes in well-defined packages. There is a very large
user community and an extensive literature. The comp.lang.perl.*
newsgroups and several of the mailing lists provide free answers to your
questions in near real-time. Perl has traditionally been supported by
Larry, scores of software designers and developers, and myriad
programmers, all working for free to create a useful thing to make life
better for everyone.

However, these answers may not suffice for managers who require a
purchase order from a company whom they can sue should anything go awry.
Or maybe they need very serious hand-holding and contractual obligations.
Shrink-wrapped CDs with perl on them are available from several sources if
that will help. For example, many Perl books include a distribution of perl,
as do the O'Reilly Perl Resource Kits (in both the Unix flavor
and in the proprietary Microsoft flavor); the free Unix distributions
also all come with perl.

=head2 Where do I send bug reports?

(contributed by brian d foy)

First, ensure that you've found an actual bug. Second, ensure you've
found an actual bug.

If you've found a bug with the perl interpreter or one of the modules
in the standard library (those that come with Perl), you can use the
L<perlbug> utility that comes with Perl (>= 5.004). It collects
information about your installation to include with your message, then
sends the message to the right place.

To determine if a module came with your version of Perl, you can
use the C<Module::CoreList> module. It has the information about
the modules (with their versions) included with each release of Perl.

If C<Module::CoreList> is not installed on your system, check out
http://perlpunks.de/corelist .

Every CPAN module has a bug tracker set up in RT, http://rt.cpan.org .
You can submit bugs to RT either through its web interface or by
email. To email a bug report, send it to
bug-E<lt>distribution-nameE<gt>@rt.cpan.org . For example, if you
wanted to report a bug in C<Business::ISBN>, you could send a message to
bug-Business-ISBN@rt.cpan.org .

Some modules might have special reporting requirements, such as a
Sourceforge or Google Code tracking system, so you should check the
module documentation too.

=head2 What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org?

Perl.com ( http://www.perl.com/ ) used to be part of the O'Reilly
Network, a subsidiary of O'Reilly Media. Although it retains most of
the original content from its O'Reilly Network, it is now hosted by
The Perl Foundation.

The Perl Foundation is an advocacy organization for the Perl language
which maintains the web site ( http://www.perl.org/ ) as a general
advocacy site for the Perl language. It uses the domain to provide
general support services to the Perl community, including the hosting
of mailing lists, web sites, and other services. There are also many
other sub-domains for special topics like learning Perl, Perl news,
jobs in Perl, such as:

        http://www.perl.org/
        http://learn.perl.org/
        http://jobs.perl.org/
        http://lists.perl.org/

Perl Mongers uses the pm.org domain for services related to Perl user
groups, including the hosting of mailing lists and web sites. See the
Perl Mongers website ( http://www.pm.org/ ) for more information about
joining, starting, or requesting services for a Perl user group.

CPAN, or the Comprehensive Perl Archive Network (
http://www.cpan.org/ ), is a replicated, worldwide repository of Perl
software. See I<What is CPAN?> in L<perlfaq2>.

=head1 AUTHOR AND COPYRIGHT

Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
other authors as noted. All rights reserved.

This documentation is free; you can redistribute it and/or modify it
under the same terms as Perl itself.

Irrespective of its distribution, all code examples here are in the public
domain. You are permitted and encouraged to use this code and any
derivatives thereof in your own programs for fun or for profit as you
see fit. A simple comment in the code giving credit to the FAQ would
be courteous but is not required.