PERLFAQ2

perlfaq2 − Obtaining and Learning about Perl

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

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).

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/

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 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.

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 "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 @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. @INC is also printed as part of the output of

    % perl −V

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

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

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

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.

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 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 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.

Is there an ISO or ANSI certified version of Perl?

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

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 "man perl" if you’re on a system resembling Unix. This will lead you to other important man pages, including how to set your $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 "perldoc perl" in case your system doesn’t have a proper man command, or it’s been misinstalled. If that doesn’t work, try looking in /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 perlfaq2 for more details.

Tutorial documents are included in current or upcoming Perl releases include perltoot for objects or perlboot for a beginner’s approach to objects, perlopentut for file opening semantics, perlreftut for managing references, perlretut for regular expressions, perlthrtut for threads, perldebtut for debugging, and 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

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 "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.

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.

Perl Books

A number of books on Perl and/or CGI programming are available. A few of these are good, some are OK , but many aren’t worth your money. There is a list of these books, some with extensive reviews, at http://books.perl.org/ . If you don’t see your book listed here, you can write to perlfaq−workers@perl.org .

The incontestably definitive reference book on Perl, written by the creator of Perl, is Programming Perl:

        Programming Perl (the "Camel Book"):
        by Larry Wall, Tom Christiansen, and Jon Orwant
        ISBN 0−596−00027−8  [3rd edition July 2000]
        http://www.oreilly.com/catalog/pperl3/
        (English, translations to several languages are also available)

The companion volume to the Camel containing thousands of real-world examples, mini-tutorials, and complete programs is:

        The Perl Cookbook (the "Ram Book"):
        by Tom Christiansen and Nathan Torkington,
            with Foreword by Larry Wall
        ISBN 0−596−00313−7 [2nd Edition August 2003]
        http://www.oreilly.com/catalog/perlckbk2/

If you’re already a seasoned programmer, then the Camel Book might suffice for you to learn Perl. If you’re not, check out the Llama book:

        Learning Perl
        by Randal L. Schwartz, Tom Phoenix, and brian d foy
        ISBN 0−596−10105−8 [4th edition July 2005]
        http://www.oreilly.com/catalog/learnperl4/

And for more advanced information on writing larger programs, presented in the same style as the Llama book, continue your education with the Alpaca book:

        Intermediate Perl (the "Alpaca Book")
        by Randal L. Schwartz and brian d foy, with Tom Phoenix (foreword by Damian Conway)
        ISBN 0−596−10206−2 [1st edition March 2006]
        http://www.oreilly.com/catalog/lrnperlorm/

Addison-Wesley ( http://www.awlonline.com/ ) and Manning ( http://www.manning.com/ ) are also publishers of some fine Perl books such as Object Oriented Programming with Perl by Damian Conway and Network Programming with Perl by Lincoln Stein.

An excellent technical book discounter is Bookpool at http://www.bookpool.com/ where a 30% discount or more is not unusual.

What follows is a list of the books that the FAQ authors found personally useful. Your mileage may (but, we hope, probably won’t) vary.

Recommended books on (or mostly on) Perl follow.

References

        Programming Perl
        by Larry Wall, Tom Christiansen, and Jon Orwant
        ISBN 0−596−00027−8 [3rd edition July 2000]
        http://www.oreilly.com/catalog/pperl3/

        Perl 5 Pocket Reference
        by Johan Vromans
        ISBN 0−596−00374−9 [4th edition July 2002]
        http://www.oreilly.com/catalog/perlpr4/

Tutorials

        Beginning Perl
        by James Lee
        ISBN 1−59059−391−X [2nd edition August 2004]
        http://apress.com/book/bookDisplay.html?bID=344

        Elements of Programming with Perl
        by Andrew L. Johnson
        ISBN 1−884777−80−5 [1st edition October 1999]
        http://www.manning.com/johnson/

        Learning Perl
        by Randal L. Schwartz, Tom Phoenix, and brian d foy
        ISBN 0−596−52010−7 [5th edition June 2008]
        http://oreilly.com/catalog/9780596520106/

        Intermediate Perl (the "Alpaca Book")
        by Randal L. Schwartz and brian d foy, with Tom Phoenix (foreword by Damian Conway)
        ISBN 0−596−10206−2 [1st edition March 2006]
        http://www.oreilly.com/catalog/intermediateperl/

        Mastering Perl
        by brian d foy
        ISBN 0−596−52724−1 [1st edition July 2007]
        http://www.oreilly.com/catalog/9780596527242/

Task-Oriented

        Writing Perl Modules for CPAN
        by Sam Tregar
        ISBN 1−59059−018−X [1st edition Aug 2002]
        http://apress.com/book/bookDisplay.html?bID=14

        The Perl Cookbook
        by Tom Christiansen and Nathan Torkington
            with foreword by Larry Wall
        ISBN 1−56592−243−3 [1st edition August 1998]
        http://www.oreilly.com/catalog/cookbook/

        Effective Perl Programming
        by Joseph Hall
        ISBN 0−201−41975−0 [1st edition 1998]
        http://www.awl.com/

        Real World SQL Server Administration with Perl
        by Linchi Shea
        ISBN 1−59059−097−X [1st edition July 2003]
        http://apress.com/book/bookDisplay.html?bID=171

Special Topics

        Perl Best Practices
        by Damian Conway
        ISBN: 0−596−00173−8 [1st edition July 2005]
        http://www.oreilly.com/catalog/perlbp/

        Higher Order Perl
        by Mark−Jason Dominus
        ISBN: 1558607013 [1st edition March 2005]
        http://hop.perl.plover.com/

        Perl 6 Now: The Core Ideas Illustrated with Perl 5
        by Scott Walters
        ISBN 1−59059−395−2 [1st edition December 2004]
        http://apress.com/book/bookDisplay.html?bID=355

        Mastering Regular Expressions
        by Jeffrey E. F. Friedl
        ISBN 0−596−00289−0 [2nd edition July 2002]
        http://www.oreilly.com/catalog/regex2/

        Network Programming with Perl
        by Lincoln Stein
        ISBN 0−201−61571−1 [1st edition 2001]
        http://www.awlonline.com/

        Object Oriented Perl
        Damian Conway
            with foreword by Randal L. Schwartz
        ISBN 1−884777−79−1 [1st edition August 1999]
        http://www.manning.com/conway/

        Data Munging with Perl
        Dave Cross
        ISBN 1−930110−00−6 [1st edition 2001]
        http://www.manning.com/cross

        Mastering Perl/Tk
        by Steve Lidie and Nancy Walsh
        ISBN 1−56592−716−8 [1st edition January 2002]
        http://www.oreilly.com/catalog/mastperltk/

        Extending and Embedding Perl
        by Tim Jenness and Simon Cozens
        ISBN 1−930110−82−0 [1st edition August 2002]
        http://www.manning.com/jenness

        Perl Debugger Pocket Reference
        by Richard Foley
        ISBN 0−596−00503−2 [1st edition January 2004]
        http://www.oreilly.com/catalog/perldebugpr/

        Pro Perl Debugging
        by Richard Foley with Andy Lester
        ISBN 1−59059−454−1 [1st edition July 2005]
        http://www.apress.com/book/view/1590594541

Which magazines have Perl content?

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 $foo Magazin, a german magazine dedicated to Perl, at ( http://www.foo−magazin.de ).

Magazines that frequently carry quality articles on Perl include The Perl Review ( http://www.theperlreview.com ), Unix Review ( http://www.unixreview.com/ ), Linux Magazine ( http://www.linuxmagazine.com/ ), and Usenix’s newsletter/magazine to its members, 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, The Perl Journal contains tutorials, demonstrations, case studies, announcements, contests, and much more. 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, TPJ moved to a reader-supported monthly e−zine format in which subscribers can download issues as PDF documents. In 2006, TPJ merged with Dr. Dobbs Journal (online edition). To read old TPJ articles, see http://www.ddj.com/ .

What mailing lists are there for Perl?

Most of the major modules (Tk, CGI , 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/

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.

Where can I buy a commercial version of perl?

In a real sense, perl already 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.

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 "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 "Module::CoreList" module. It has the information about the modules (with their versions) included with each release of Perl.

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−<distribution−name>@rt.cpan.org . For example, if you wanted to report a bug in "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.

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

Perl.com at http://www.perl.com/ is part of the O’Reilly Network, a subsidiary of O’Reilly Media.

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://learn.perl.org/
        http://use.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 user group web site at http://www.pm.org/ for more information about joining, starting, or requesting services for a Perl user group.

http://www.cpan.org/ is the Comprehensive Perl Archive Network, a replicated worldwide repository of Perl software, see the What is CPAN ? question earlier in this document.

Revision: $Revision$

Date: $Date$

See perlfaq for source control details and availability.

Copyright (c) 1997−2009 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.