perlfaq - frequently asked questions about Perl
perlfaq - frequently asked questions about Perl ($Date: 1999/05/23 20:38:02 $)
This document is structured into the following sections:
- perlfaq: Structural overview of the FAQ.
- the perlfaq1 manpage: General Questions About Perl
Very general, high-level information about Perl.
- the perlfaq2 manpage: Obtaining and Learning about Perl
Where to find source and documentation to Perl, support,
and related matters.
- the perlfaq3 manpage: Programming Tools
Programmer tools and programming support.
- the perlfaq4 manpage: Data Manipulation
Manipulating numbers, dates, strings, arrays, hashes, and
miscellaneous data issues.
- the perlfaq5 manpage: Files and Formats
I/O and the ``f'' issues: filehandles, flushing, formats and footers.
- the perlfaq6 manpage: Regexps
Pattern matching and regular expressions.
- the perlfaq7 manpage: General Perl Language Issues
General Perl language issues that don't clearly fit into any of the
- the perlfaq8 manpage: System Interaction
Interprocess communication (IPC), control over the user-interface
(keyboard, screen and pointing devices).
- the perlfaq9 manpage: Networking
Networking, the Internet, and a few on the web.
This document is posted regularly to comp.lang.perl.announce and
several other related newsgroups. It is available in a variety of
formats from CPAN in the /CPAN/doc/FAQs/FAQ/ directory, or on the web
at http://www.perl.com/perl/faq/ .
You may mail corrections, additions, and suggestions to
email@example.com . This alias should not be
used to ask FAQs. It's for fixing the current FAQ.
Send questions to the comp.lang.perl.misc newsgroup.
Your questions will probably go unread, unless they're suggestions of
new questions to add to the FAQ, in which case they should have gone
to the firstname.lastname@example.org instead.
You should have read section 2 of this faq. There you would have
learned that comp.lang.perl.misc is the appropriate place to go for
free advice. If your question is really important and you require a
prompt and correct answer, you should hire a consultant.
When I first began the Perl FAQ in the late 80s, I never realized it
would have grown to over a hundred pages, nor that Perl would ever become
so popular and widespread. This document could not have been written
without the tremendous help provided by Larry Wall and the rest of the
Copyright (c) 1997-1999 Tom Christiansen and Nathan Torkington.
All rights reserved.
When included as part of the Standard Version of Perl, or as part of
its complete documentation whether printed or otherwise, this work
may be distributed only under the terms of Perl's Artistic License.
Any distribution of this file or derivatives thereof outside
of that package require that special arrangements be made with
Irrespective of its distribution, all code examples in these files
are hereby placed into the public domain. You are permitted and
encouraged to use this code in your own programs for fun
or for profit as you see fit. A simple comment in the code giving
credit would be courteous but is not required.
This information is offered in good faith and in the hope that it may
be of use, but is not guaranteed to be correct, up to date, or suitable
for any particular purpose whatsoever. The authors accept no liability
in respect of this information or its use.
Extensive updates from the net in preparation for 5.6 release.
More minor touch-ups. Added new question at the end
of perlfaq7 on variable names within variables.
Small touchups here and there. Added all questions in this
document as a sort of table of contents.
Significant changes throughout in preparation for the 5.005
Style and whitespace changes from Chip, new question on reading one
character at a time from a terminal using POSIX from Tom.
Added http://www.oasis.leo.org/perl/ to the perlfaq2 manpage. Style fix to
the perlfaq3 manpage. Added floating point precision, fixed complex number
arithmetic, cross-references, caveat for Text::Wrap, alternative
answer for initial capitalizing, fixed incorrect regexp, added example
of Tie::IxHash to the perlfaq4 manpage. Added example of passing and storing
filehandles, added commify to the perlfaq5 manpage. Restored variable suicide,
and added mass commenting to the perlfaq7 manpage. Added Net::Telnet, fixed
backticks, added reader/writer pair to telnet question, added FindBin,
grouped module questions together in the perlfaq8 manpage. Expanded caveats
for the simple URL extractor, gave LWP example, added CGI security
question, expanded on the mail address answer in the perlfaq9 manpage.
Added more info to the binary distribution section of the perlfaq2 manpage.
Added Net::Telnet to the perlfaq6 manpage. Fixed typos in the perlfaq8 manpage. Added
mail sending example to the perlfaq9 manpage. Added Merlyn's columns to
the perlfaq2 manpage.
Added the DATE to the NAME section, indicating which sections have
Mentioned SIGPIPE and the perlipc manpage in the forking open answer in
the perlfaq8 manpage.
Fixed description of a regular expression in the perlfaq4 manpage.
- /March/97 Version
Various typos fixed throughout.
Added new question on Perl BNF on the perlfaq7 manpage.
- Initial Release: 11/March/97
This is the initial release of version 3 of the FAQ; consequently there
have been no changes since its initial release.
perlfaq - frequently asked questions about Perl