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=head1 NAME

perlfaq2 - Obtaining and Learning about Perl ($Revision: 1.31 $, $Date: 1999/04/14 03:46:19 $)

=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 this at http://www.perl.com/CPAN/src/latest.tar.gz , which
in standard Internet format (a gzipped archive in POSIX tar format).

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, and the Amiga.  There are also the beginnings of support
for MPE/iX.

Binary distributions for some proprietary platforms, including
Apple systems, can be found http://www.perl.com/CPAN/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?

If you don't have a C compiler because your vendor for whatever
reasons did not include one with your system, the best thing to do is
grab a binary version of gcc from the net and use that to compile perl
with.  CPAN only has binaries for systems that are terribly hard to
get free compilers for, not for Unix systems.

Some URLs that might help you are:

    http://language.perl.com/info/software.html
    http://www.perl.com/latest/
    http://www.perl.com/CPAN/ports/

Someone looking for a Perl for Win16 might look to Laszlo Molnar's djgpp
port in http://www.perl.com/CPAN/ports/msdos/ , which comes with clear
installation instructions.  A simple installation guide for MS-DOS using
Ilya Zakharevich's OS/2 port is available at
http://www.cs.ruu.nl/%7Epiet/perl5dos.html
and similarly for Windows 3.1 at http://www.cs.ruu.nl/%7Epiet/perlwin3.html .

=head2 I don't have a C compiler on my system.  How can I compile perl?

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.

=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 @INC which perl is looking for.

    % perl -e 'print join("\n",@INC)'

If this command lists any paths which 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 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
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 huge archive
replicated on dozens 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 machine for CPAN is
ftp://ftp.funet.fi/pub/languages/perl/CPAN/, but you can use the
address http://www.perl.com/CPAN/CPAN.html to fetch a copy from a
"site near you".  See http://www.perl.com/CPAN (without a slash at the
end) for how this process works.

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 file is downloadable as
ftp://ftp.funet.fi/pub/languages/perl/CPAN/misc/japh .

Considering that there are hundreds of 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.

=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
$MANPATH.  If you're not on a Unix system, access to the documentation
will be different; for example, it might be only in HTML format.  But all
proper Perl installations have fully-accessible documentation.

You might also try C<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 the CPAN/doc directory, which contains the
complete documentation in various formats, including native pod,
troff, html, and plain text.  There's also a web page at
http://www.perl.com/perl/info/documentation.html that might help.

Many good books have been written about Perl -- see the section below
for more details.

Tutorial documents are included in current or upcoming Perl releases
include L<perltoot> for objects, L<perlopentut> for file opening
semantics, L<perlreftut> for managing references, and L<perlxstut>
for linking C and Perl together.  There may be more by the 
time you read this.  The following URLs might also be of 
assistance:

    http://language.perl.com/info/documentation.html
    http://reference.perl.com/query.cgi?tutorials

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

The now defunct comp.lang.perl newsgroup has been superseded by the
following groups:

    comp.lang.perl.announce 		Moderated announcement group
    comp.lang.perl.misc     		Very busy group about Perl in general
    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

    comp.infosystems.www.authoring.cgi 	Writing CGI scripts for the Web.

There is also Usenet gateway to the mailing list used by the crack
Perl development team (perl5-porters) at
news://news.perl.com/perl.porters-gw/ .

=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 AltaVista
(http://www.altavista.com), Deja (http://www.deja.com), and
search CPAN.  This is faster and more productive than just posting
a request.

=head2 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.  Tom
Christiansen maintains a list of these books, some with extensive
reviews, at http://www.perl.com/perl/critiques/index.html.

The incontestably definitive reference book on Perl, written by
the creator of Perl, is now in its second edition:

    Programming Perl (the "Camel Book"):
	by Larry Wall, Tom Christiansen, and Randal Schwartz
        ISBN 1-56592-149-6      (English)
        ISBN 4-89052-384-7      (Japanese)
	URL: http://www.oreilly.com/catalog/pperl2/
    (French, German, Italian, and Hungarian translations also
    available)

The companion volume to the Camel containing thousands
of real-world examples, mini-tutorials, and complete programs
(first premiering at the 1998 Perl Conference), is:

    The Perl Cookbook (the "Ram Book"):
	by Tom Christiansen and Nathan Torkington, 
		    with Foreword by Larry Wall
	ISBN: 1-56592-243-3
	URL:  http://perl.oreilly.com/cookbook/

If you're already a hard-core systems programmer, then the Camel Book
might suffice for you to learn Perl from.  But if you're not, check
out:

    Learning Perl (the "Llama Book"):
	by Randal Schwartz and Tom Christiansen 
		    with Foreword by Larry Wall
	ISBN: 1-56592-284-0
	URL:  http://www.oreilly.com/catalog/lperl2/

Despite the picture at the URL above, the second edition of "Llama
Book" really has a blue cover, and is updated for the 5.004 release
of Perl.  Various foreign language editions are available, including
I<Learning Perl on Win32 Systems> (the Gecko Book).

If you're not an accidental programmer, but a more serious and possibly
even degreed computer scientist who doesn't need as much hand-holding as
we try to provide in the Llama or its defurred cousin the Gecko, please
check out the delightful book, I<Perl: The Programmer's Companion>,
written by Nigel Chapman.

You can order O'Reilly books directly from O'Reilly & Associates,
1-800-998-9938.  Local/overseas is 1-707-829-0515.  If you can
locate an O'Reilly order form, you can also fax to 1-707-829-0104.
See http://www.ora.com/ on the Web.

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; those marked with
a star may be ordered from O'Reilly.

=over

=item References

    *Programming Perl
	by Larry Wall, Tom Christiansen, and Randal L. Schwartz

    *Perl 5 Desktop Reference
        by Johan Vromans

    *Perl in a Nutshell
        by Ellen Siever, Stephan Spainhour, and Nathan Patwardhan

=item Tutorials
		
    *Learning Perl [2nd edition]
	by Randal L. Schwartz and Tom Christiansen
	    with foreword by Larry Wall

    *Learning Perl on Win32 Systems
	by Randal L. Schwartz, Erik Olson, and Tom Christiansen,
	    with foreword by Larry Wall

    Perl: The Programmer's Companion
	by Nigel Chapman

    Cross-Platform Perl 
	by Eric F. Johnson

    MacPerl: Power and Ease 
	by Vicki Brown and Chris Nandor, foreword by Matthias Neeracher

=item Task-Oriented 

    *The Perl Cookbook
	by Tom Christiansen and Nathan Torkington
	    with foreword by Larry Wall

    Perl5 Interactive Course [2nd edition]
	by Jon Orwant

    *Advanced Perl Programming 
	by Sriram Srinivasan

    Effective Perl Programming 
	by Joseph Hall

=item Special Topics

    *Mastering Regular Expressions
	by Jeffrey Friedl

    How to Set up and Maintain a World Wide Web Site [2nd edition]
	by Lincoln Stein

    *Learning Perl/Tk
        by Nancy Walsh

=back

=head2 Perl in Magazines

The first and only periodical devoted to All Things Perl, I<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.  It is published quarterly under the gentle hand of its
editor, Jon Orwant.  See http://www.tpj.com/ or send mail to
subscriptions@tpj.com .

Beyond this, magazines that frequently carry high-quality articles
on Perl are I<Web Techniques> (see http://www.webtechniques.com/),
I<Performance Computing> (http://www.performance-computing.com/), and Usenix's
newsletter/magazine to its members, I<login:>, at http://www.usenix.org/.
Randal's Web Technique's columns are available on the web at
http://www.stonehenge.com/merlyn/WebTechniques/.

=head2 Perl on the Net: FTP and WWW Access

To get the best (and possibly cheapest) performance, pick a site from
the list below and use it to grab the complete list of mirror sites.
From there you can find the quickest site for you.  Remember, the
following list is I<not> the complete list of CPAN mirrors.

  http://www.perl.com/CPAN-local
  http://www.perl.com/CPAN	(redirects to an ftp mirror)
  http://www.perl.org/CPAN
  ftp://ftp.funet.fi/pub/languages/perl/CPAN/
  http://www.cs.ruu.nl/pub/PERL/CPAN/
  ftp://ftp.cs.colorado.edu/pub/perl/CPAN/

=head2 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.  The Perl Institute attempts to maintain a
list of mailing lists at:

	http://www.perl.org/maillist.html

=head2 Archives of comp.lang.perl.misc

Have you tried Deja or AltaVista?  Those are the 
best archives.  Just look up "*perl*" as a newsgroup.

    http://www.deja.com/dnquery.xp?QRY=&DBS=2&ST=PS&defaultOp=AND&LNG=ALL&format=terse&showsort=date&maxhits=25&subjects=&groups=*perl*&authors=&fromdate=&todate=

You'll probably want to trim that down a bit, though.

ftp.cis.ufl.edu:/pub/perl/comp.lang.perl.*/monthly has an almost
complete collection dating back to 12/89 (missing 08/91 through
12/93).  They are kept as one large file for each month.

You'll probably want more a sophisticated query and retrieval mechanism
than a file listing, preferably one that allows you to retrieve
articles using a fast-access indices, keyed on at least author, date,
subject, thread (as in "trn") and probably keywords.  The best
solution the FAQ authors know of is the MH pick command, but it is
very slow to select on 18000 articles.

If you have, or know where can be found, the missing sections, please
let perlfaq-suggestions@perl.com know.

=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 myriads of
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 carry a Perl distribution
on them, 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.

Or you can purchase a real support contract.  Although Cygnus historically
provided this service, they no longer sell support contracts for Perl.
Instead, the Paul Ingram Group will be taking up the slack through The
Perl Clinic.  The following is a commercial from them:

"Do you need professional support for Perl and/or Oraperl?  Do you need
a support contract with defined levels of service?  Do you want to pay
only for what you need?

"The Paul Ingram Group has provided quality software development and
support services to some of the world's largest corporations for ten
years.  We are now offering the same quality support services for Perl
at The Perl Clinic.  This service is led by Tim Bunce, an active perl
porter since 1994 and well known as the author and maintainer of the
DBI, DBD::Oracle, and Oraperl modules and author/co-maintainer of The
Perl 5 Module List.  We also offer Oracle users support for Perl5
Oraperl and related modules (which Oracle is planning to ship as part
of Oracle Web Server 3).  20% of the profit from our Perl support work
will be donated to The Perl Institute."

For more information, contact The Perl Clinic:

    Tel:    +44 1483 424424
    Fax:    +44 1483 419419
    Web:    http://www.perl.co.uk/
    Email:  perl-support-info@perl.co.uk or Tim.Bunce@ig.co.uk

See also www.perl.com for updates on tutorials, training, and support.

=head2 Where do I send bug reports?

If you are reporting a bug in the perl interpreter or the modules
shipped with Perl, use the I<perlbug> program in the Perl distribution or
mail your report to perlbug@perl.com .

If you are posting a bug with a non-standard port (see the answer to
"What platforms is Perl available for?"), a binary distribution, or a
non-standard module (such as Tk, CGI, etc), then please see the
documentation that came with it to determine the correct place to post
bugs.

Read the perlbug(1) man page (perl5.004 or later) for more information.

=head2 What is perl.com?  

The perl.com domain is owned by Tom Christiansen, who created it as a
public service long before perl.org came about.  Despite the name, it's a
pretty non-commercial site meant to be a clearinghouse for information
about all things Perlian, accepting no paid advertisements, bouncy
happy GIFs, or silly Java applets on its pages.  The Perl Home Page at
http://www.perl.com/ is currently hosted on a T3 line courtesy of Songline
Systems, a software-oriented subsidiary of O'Reilly and Associates.
Other starting points include 

    http://language.perl.com/
    http://conference.perl.com/
    http://reference.perl.com/

=head1 AUTHOR AND COPYRIGHT

Copyright (c) 1997-1999 Tom Christiansen and Nathan Torkington.
All rights reserved.

When included as an integrated part of the Standard Distribution
of Perl or of its documentation (printed or otherwise), this works is
covered under Perl's Artistic License.  For separate distributions of
all or part of this FAQ outside of that, see L<perlfaq>.

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.