Perl — Mediated Wiki

{{Short description|Interpreted programming language first released in 1987}} {{Other uses|Perl (disambiguation)}} {{Distinguish|PEARL (programming language)}} {{Use mdy dates|date=September 2014}} {{Infobox programming language | name = Perl | logo = perl-logo.svg | paradigm = Multi-paradigm | designer = Larry Wall | developer = Larry Wall | typing = Dynamic | influenced = CoffeeScript,{{citation needed|date=January 2016}} Groovy,{{citation needed|date=February 2016}} JavaScript, Julia, LPC, PHP, Python, Raku, Ruby, PowerShell | license = Artistic 1.0<ref name="artistic-1.0"/><ref name="artistic-1.0-git"/> or GNU General Public License version 1 or any later version<ref name="licensing"/> | website = {{URL|https://www.perl.org/|perl.org}} | wikibooks = Perl Programming | released = {{Start date and age|1987|12|18}}<ref name="perltimeline"/> | latest release version = 5.42.1<ref>{{cite web |url=https://www.nntp.perl.org/group/perl.perl5.porters/2026/03/msg270767.html |title=Perl v5.42.1 is now available! |access-date=2026-03-08 |publisher=www.nntp.perl.org}}</ref> | latest release date = {{Start date and age|2026|03|08|df=yes}} | latest preview version = 5.43.8<ref>{{cite web |url=https://www.nntp.perl.org/group/perl.perl5.porters/2026/02/msg270752.html |title=Release announcement for perl v5.43.8 |access-date=2026-02-21 |publisher=www.nntp.perl.org}}</ref> | latest preview date = {{Start date and age|2026|02|20|df=yes}} | influenced by=AWK, BASIC, C, C++, Lisp, sed, Unix shell<ref>{{cite web|title=Programming is Hard, Let's Go Scripting...|last1=Wall|first1=Larry|author1-link=Larry Wall|date=December 12, 2007|url=https://www.perl.com/pub/2007/12/06/soto-11.html/|quote=All language designers have their occasional idiosyncracies. I’m just better at it than most.|access-date=April 14, 2019|archive-date=July 28, 2017|archive-url=https://web.archive.org/web/20170728023959/http://www.perl.com/pub/2007/12/06/soto-11.html|url-status=live}}</ref> | programming language=C | operating system=Cross-platform | file ext=.plx, .pls, .pl, .pm, .xs, .t, .pod, .cgi, .psgi }}

'''Perl''' is a high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym,<ref>{{cite web |url=http://learn.perl.org/faq/perlfaq1.html#Whats-the-difference-between-perl-and-Perl |title=General Questions About Perl |last=Lapworth |first=Leo |publisher=Perl.org |work=Perl FAQ |access-date=February 24, 2012 |archive-date=May 28, 2013 |archive-url=https://web.archive.org/web/20130528001715/http://learn.perl.org/faq/perlfaq1.html#Whats-the-difference-between-perl-and-Perl |url-status=live}}</ref> there are various backronyms in use, including "Practical Extraction and Reporting Language".<ref>{{cite web |url=http://linux.die.net/man/1/perl |title=perl(1): Practical Extraction/Report Language - Linux man page |publisher=Linux.die.net |access-date=2013-07-23 |archive-date=June 3, 2013 |archive-url=https://web.archive.org/web/20130603152544/http://linux.die.net/man/1/perl |url-status=live}}</ref>

Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier.<ref name="sheppard00">{{cite web |url=http://www.perl.com/pub/2000/10/begperl1.html |title=Beginner's Introduction to Perl |last=Sheppard |first=Doug |date=2000-10-16 |publisher=dev.perl.org |access-date=2011-01-08 |archive-date=June 5, 2011 |archive-url=https://web.archive.org/web/20110605130400/http://www.perl.com/pub/2000/10/begperl1.html |url-status=live}}</ref><ref name=":0">{{Cite web |title=Larry Wall, the Guru of Perl |url=https://www.linuxjournal.com/article/3394 |access-date=2023-08-30 |website=Linux Journal}}</ref> Since then, it has undergone many changes and revisions. Perl originally was not capitalized and the name was changed to being capitalized by the time Perl 4 was released.<ref name=":0"/> The latest release is Perl 5, first released in 1994. From 2000 to October 2019 a sixth version of Perl was in development; the sixth version's name was changed to Raku.<ref>{{cite web |url=https://www.perl.org/about.html |title=About Perl |publisher=perl.org |quote="Perl" is a family of languages, "Perl 6" is part of the family, but it is a separate language that has its own development team. Its existence has no significant impact on the continuing development of "Perl 5". |access-date=2013-04-20 |archive-date=November 6, 2015 |archive-url=https://web.archive.org/web/20151106051931/https://www.perl.org/about.html |url-status=live}}</ref><ref>{{cite web |url=https://github.com/Raku/problem-solving/blob/master/solutions/language/Path-to-Raku.md |title=Path to Raku |publisher=GitHub |quote=This document describes the steps to be taken to effectuate a rename of Perl 6 to Raku |access-date=2021-01-14 |archive-date=November 12, 2020 |archive-url=https://web.archive.org/web/20201112035821/https://github.com/Raku/problem-solving/blob/master/solutions/language/Path-to-Raku.md |url-status=live}}</ref> Both languages continue to be developed independently by different development teams which liberally borrow ideas from each other.

Perl borrows features from other programming languages including C, sh, AWK, and sed.<ref name="perltimeline">{{cite web |url=http://history.perl.org/PerlTimeline.html |title=The Timeline of Perl and its Culture (v3.0_0505) |last1=Ashton |first1=Elaine |year=1999 |access-date=March 12, 2004 |archive-date=January 11, 2013 |archive-url=https://web.archive.org/web/20130111100906/http://history.perl.org/PerlTimeline.html |url-status=live}}</ref> It provides text processing facilities without the arbitrary data-length limits of many contemporary Unix command line tools.<ref name="programmingperl2">{{cite book |title=Programming Perl, Third Edition |date=July 2000 |publisher=O'Reilly Media |isbn=978-0-596-00027-1 |last1=Wall|first1=Larry|author-link1=Larry Wall|last2= Christiansen|first2=Tom|last3=Orwant|first3=Jon}}</ref> Perl is a highly expressive programming language: source code for a given algorithm can be short and highly compressible.<ref>{{Cite web|title=How programs are measured |url=https://benchmarksgame-team.pages.debian.net/benchmarksgame/how-programs-are-measured.html#source-code|access-date=2020-10-05|website=Computer Language Benchmarks Game, Debian.net|archive-date=July 12, 2020|archive-url=https://web.archive.org/web/20200712000728/https://benchmarksgame-team.pages.debian.net/benchmarksgame/how-programs-are-measured.html#source-code|url-status=live}}</ref><ref>{{Cite web|title=RSA in 3 lines of perl - Everything2.com|url=https://everything2.com/title/RSA+in+3+lines+of+perl|access-date=2020-10-05|website=everything2.com|date=November 26, 2000 |archive-date=October 8, 2020|archive-url=https://web.archive.org/web/20201008120935/https://everything2.com/title/RSA+in+3+lines+of+perl|url-status=live}}</ref>

Perl gained widespread popularity in the mid-1990s as a CGI scripting language, in part due to its powerful regular expression and string parsing abilities.<ref>{{cite web |url=http://www.catb.org/esr/writings/taoup/html/ch14s04.html#perl |title=Language Evaluations |quote=Perl's strongest point is its extremely powerful built-in facilities for pattern-directed processing of textual, line-oriented data formats; it is unsurpassed at this. |access-date=January 30, 2015 |archive-date=March 10, 2015 |archive-url=https://web.archive.org/web/20150310123855/http://www.catb.org/esr/writings/taoup/html/ch14s04.html#perl |url-status=live}}</ref><ref>{{cite web |url=http://www.cio.com/article/2437271/developer/you-used-perl-to-write-what--.html |title=You Used Perl to Write WHAT?! |date=January 24, 2008 |quote=perl has always been the go-to language for any task that involves pattern-matching input |access-date=February 4, 2015 |archive-date=February 4, 2015 |archive-url=https://web.archive.org/web/20150204175543/http://www.cio.com/article/2437271/developer/you-used-perl-to-write-what--.html |url-status=live}}</ref><ref>{{cite web |url=http://archive.oreilly.com/pub/a/oreilly/perl/news/importance_0498.html |title=The Importance of Perl |quote=Perl's unparalleled ability to process text... |access-date=February 4, 2015 |archive-url=https://web.archive.org/web/20150202010003/http://archive.oreilly.com/pub/a/oreilly/perl/news/importance_0498.html |archive-date=February 2, 2015 |url-status=dead |df=mdy-all}}</ref><ref name="roderick02">{{cite book |title=Advanced Linux Networking |url=https://archive.org/details/linux00libg_999 |url-access=limited |date=June 21, 2002 |publisher=Addison-Wesley Professional |isbn=978-0-201-77423-8 |page=[https://archive.org/details/linux00libg_999/page/n595 594] |last1=Smith |first1=Roderick W.}}</ref> In addition to CGI, Perl 5 is used for system administration, network programming, finance, bioinformatics, and other applications, such as for graphical user interfaces (GUIs). It has been nicknamed "the Swiss Army chainsaw of scripting languages" because of its flexibility and power.<ref>{{cite web |url=http://www.perl.com/pub/a/2000/10/begperl1.html |title=Beginner's Introduction to Perl |last=Sheppard |first=Doug |date=2000-10-16 |publisher=O'Reilly Media |access-date=2008-07-27 |archive-date=June 4, 2008 |archive-url=https://web.archive.org/web/20080604140740/http://www.perl.com/pub/a/2000/10/begperl1.html |url-status=live}}</ref> In 1998, it was also referred to as the "duct tape that holds the Internet together", in reference to both its ubiquitous use as a glue language and its perceived inelegance.<ref name="leonard98">{{cite news |url=http://www.salon.com/1998/10/13/feature_269/ |title=The joy of Perl |last=Leonard |first=Andrew |work=Salon.com |access-date=2012-06-05 |archive-date=July 6, 2012 |archive-url=https://web.archive.org/web/20120706094345/http://www.salon.com/1998/10/13/feature_269/ |url-status=live}}</ref>

== Name and logos == {{ multiple image|total_width=400 | image1=Perl-camel-small.png | caption1=The Camel symbol used by O'Reilly Media | image2=Perl onion symbol.svg | caption2=The onion logo used by The Perl Foundation }}

Perl was originally named "Pearl". Wall wanted to give the language a short name with positive connotations.<ref>{{Cite magazine |date=2016-03-07 |title=Scripting on the Lido Deck |url=https://www.wired.com/2000/10/cruise/ |access-date=2023-02-14 |magazine=Wired|archive-url=https://web.archive.org/web/20160307004219/https://www.wired.com/2000/10/cruise/ |archive-date=March 7, 2016}}</ref> However, Wall discovered the existing PEARL language before Perl's official release and dropped the "a" from the name.<ref name="richardson1999">{{cite journal|last=Richardson|first=Marjorie|date=1999-05-01|title=Larry Wall, the Guru of Perl|url=http://www.linuxjournal.com/article/3394|url-status=live|journal=Linux Journal|archive-url=https://web.archive.org/web/20130720013904/http://www.linuxjournal.com/article/3394|archive-date=July 20, 2013|access-date=2011-01-03}}</ref>

The name is occasionally expanded as a backronym: ''Practical Extraction and Report Language''<ref>{{cite book|last1=Schwartz|first1=Randal|url=https://archive.org/details/learningperl00schw_278|title=Learning Perl|last2=foy|first2=brian|last3=Phoenix|first3=Tom|date=June 16, 2011|publisher=O'Reilly Media, Inc.|isbn=978-1449313142|page=[https://archive.org/details/learningperl00schw_278/page/n27 4]|quote=Perl is sometimes called the "Practical Extraction and Report Language", although it has also been called a "Pathologically Eclectic Rubbish Lister", among other expansions. It's actually a backronym, not an acronym, since Larry Wall, Perl's creator, came up with the name first and the expansion later. That's why 'Perl' isn't in all caps. There's no point in arguing that expansion is correct: Larry endorses both.|author-link1=Randal Schwartz|author-link2=brian d foy|url-access=limited}}</ref> and Wall's own ''Pathologically Eclectic Rubbish Lister'', which is in the manual page for perl.<ref>{{cite web|last=Wall|first=Larry|author-link=Larry Wall|title=perl - The Perl language interpreter|url=http://perldoc.perl.org/perl.html#BUGS|url-status=live|archive-url=https://web.archive.org/web/20130701050810/http://perldoc.perl.org/perl.html#BUGS|archive-date=July 1, 2013|access-date=2011-01-26|work=Perl 5 version 12.2 documentation}}</ref>

''Programming Perl'', published by O'Reilly Media, features a picture of a dromedary camel on the cover and is commonly called the "Camel Book".<ref name="schwartz01">{{cite book |last1=Schwartz |first1=Randal L |author-link1=Randal L. Schwartz |last2=Phoenix |first2=Tom |last3=Foy |first3=Brian |author-link3=Brian D Foy |title=Learning Perl, Third Edition |isbn=978-0-596-00132-2 |date=2007-12-06 |publisher=O'Reilly Media |url=https://archive.org/details/learningperl00schw}}</ref> This image has become an unofficial symbol of Perl. O'Reilly owns the image as a trademark but licenses it for non-commercial use, requiring only an acknowledgement and a link to www.perl.com. Licensing for commercial use is decided on a case-by-case basis.<ref name="camel">{{cite web |url=http://archive.oreilly.com/pub/a/oreilly/perl/usage |archive-url=https://web.archive.org/web/20180425080044/http://archive.oreilly.com/pub/a/oreilly/perl/usage |url-status=dead |archive-date=2018-04-25 |title=The Perl Camel Usage and Trademark Information |access-date=2011-01-09 |publisher=O'Reilly Media}}</ref> O'Reilly also provides "Programming Republic of Perl" logos for non-commercial sites and "Powered by Perl" buttons for any site that uses Perl.<ref name="camel"/>

The Perl Foundation owns an alternative symbol, an onion, which it licenses to its subsidiaries, Perl Mongers, PerlMonks, Perl.org, and others.<ref name="onion">{{cite web |url=http://www.perlfoundation.org/perl_trademark |title=Perl Trademark |access-date=2011-01-09 |publisher=The Perl Foundation |archive-url=https://web.archive.org/web/20110503211915/http://www.perlfoundation.org/perl_trademark |archive-date=May 3, 2011 |url-status=dead |df=mdy-all}}</ref> The symbol is a visual pun on pearl onion.<ref name="gillmore98">{{cite news |first=Dan |last=Gillmore |title=Republic Of Perl |date=1998-10-25 |url=https://www.chicagotribune.com/1998/10/25/republic-of-perl/ |work=Chicago Tribune |access-date=2011-01-10 |archive-date=April 30, 2011 |archive-url=https://web.archive.org/web/20110430031425/http://articles.chicagotribune.com/1998-10-25/news/9810250094_1_programmers-open-source-movement-programming-community |url-status=live}}</ref>

In 2024, a new camel logo for the language was published<ref name="2024logo">{{cite web | url=https://perladvent.org/2024/2024-12-23.html| title= A New Logo for Perl |access-date=2025-05-09 | publisher= Perl Advent Calendar 2024}}</ref> under a Creative Commons license by a small group of developers. While not an official logo, it is intended to represent both the language and the community and draws on Perl's longtime association with the camel from the O'Reilly book.

== History ==

=== Early versions ===

Larry Wall began work on Perl in 1987, while employed as a programmer at Unisys;<ref name="programmingperl2"/> he released version 1.0 on December 18, 1987.<ref name="perltimeline"/> Wall based early ''Perl'' on some methods existing languages used for text manipulation.

Perl 2, released in June 1988,<ref name="Kalita ">{{Cite book |last=Kalita |first=Jugal |url=https://books.google.com/books?id=aMuuTttVDcIC |title=On Perl: Perl for Students and Professionals |date=December 2003 |publisher=Universal-Publishers |isbn=978-1-58112-550-4 |language=en}}</ref><ref>{{Cite web |title=Perl Culture |url=https://docstore.mik.ua/orelly/perl/prog3/ch27_01.htm |access-date=2023-03-16 |website=docstore.mik.ua |language=en-US}}</ref> featured a better regular expression engine. Perl 3, released in October 1989,<ref name="Kalita "/> added support for binary data streams.<ref>{{Cite web |last=Holloway |first=Ruth |title=Perl turns 30 and its community continues to thrive |url=https://opensource.com/article/17/10/perl-turns-30 |access-date=2023-06-23 |website=Opensource.com |language=en}}</ref>

=== 1990s === {{Main|Perl 5 version history}}

Originally, the only documentation for Perl was a single lengthy man page. In 1991, ''Programming Perl'', known to many Perl programmers as the "Camel Book" because of its cover, was published and became the ''de facto'' reference for the language.<ref>{{Cite book |title=Programming Perl, 3rd Edition [Book] |url=https://www.oreilly.com/library/view/programming-perl-3rd/0596000278/ |access-date=2023-04-11 |website=www.oreilly.com |isbn=978-0-596-00027-1 |language=en}}</ref> At the same time, the Perl version number was bumped to 4, not to mark a major change in the language but to identify the version that was well documented by the book.<ref>{{Cite web |title=perlhist - the Perl history records - Perldoc Browser |url=https://perldoc.perl.org/perlhist |access-date=2023-07-28 |website=perldoc.perl.org}}</ref> Perl 4 was released in March 1991.<ref name="Kalita"/>

Perl 4 went through a series of maintenance releases, culminating in Perl 4.036 in 1993, whereupon Wall abandoned Perl 4 to begin work on Perl 5. Initial design of Perl 5 continued into 1994. The ''perl5-porters'' mailing list was established in May 1994 to coordinate work on porting Perl 5 to different platforms. It remains the primary forum for development, maintenance, and porting of Perl 5.<ref>{{Cite web |url=http://www.nntp.perl.org/group/perl.perl5.porters/ |title=perl.perl5.porters archive |access-date=2011-01-13 |publisher=perl.org |archive-date=May 1, 2011 |archive-url=https://web.archive.org/web/20110501081803/http://www.nntp.perl.org/group/perl.perl5.porters/ |url-status=live}}</ref>

Perl 5.000 was released on October 17, 1994.<ref name="perlhist">{{Cite web |url=http://perldoc.perl.org/perlhist.html |title=perlhist: the Perl history records |access-date=2011-01-21 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=January 13, 2011 |archive-url=https://web.archive.org/web/20110113030100/http://perldoc.perl.org/perlhist.html |url-status=live}}</ref> It was a nearly complete rewrite of the interpreter, and it added many new features to the language, including objects, references, lexical (my) variables, and modules. Importantly, modules provided a mechanism for extending the language without modifying the interpreter. This allowed the core interpreter to stabilize, even as it enabled ordinary Perl programmers to add new language features. Perl 5 has been in active development since then.

Perl 5.001 was released on March 13, 1995. Perl 5.002 was released on February 29, 1996 with the new prototypes feature. This allowed module authors to make subroutines that behaved like Perl builtins. Perl 5.003 was released June 25, 1996, as a security release.<ref>{{Cite web |title=Perl: Definition, History, & Facts |url=https://www.britannica.com/technology/Perl |access-date=2022-06-15 |website=Britannica.com |language=en}}</ref>

One of the most important events in Perl 5 history took place outside of the language proper and was a consequence of its module support. On October 26, 1995, the Comprehensive Perl Archive Network (CPAN) was established as a repository for the Perl language and Perl modules; {{as of|December 2022|lc=y}}, it carries over 211,850 modules in 43,865 distributions, written by more than 14,324 authors, and is mirrored worldwide at more than 245 locations.<ref>{{Cite web |url=https://www.cpan.org/ |title=CPAN |access-date=2022-12-19 |publisher=CPAN |archive-date=October 3, 2019 |archive-url=https://web.archive.org/web/20191003040107/https://www.cpan.org/ |url-status=live}}</ref>

Perl 5.004 was released on May 15, 1997, and included, among other things, the UNIVERSAL package, giving Perl a base object from which all classes were automatically derived and the ability to require versions of modules. Another significant development was the inclusion of the CGI.pm module,<ref name="5004delta">{{Cite web |url=http://perldoc.perl.org/perl5004delta.html |title=perl5004delta – what's new for perl5.004 |access-date=2011-01-08 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=February 27, 2011 |archive-url=https://web.archive.org/web/20110227200616/http://perldoc.perl.org/perl5004delta.html |url-status=live}}</ref> which contributed to Perl's popularity as a CGI scripting language.<ref name="patwardhan02">{{Cite book |last1=Patwardhan |first1=Nathan |last2=Siever |first2=Ellen |last3=Spainhour |first3=Stephen |title=Perl in a Nutshell, Second Edition |publisher=O'Reilly Media |year=2002 |isbn=978-0-596-00241-1 |url=https://archive.org/details/perlinnutshell00patw}}</ref>

Perl 5.004 added support for Microsoft Windows, Plan 9, QNX, and AmigaOS.<ref name="5004delta"/>

Perl 5.005 was released on July 22, 1998. This release included several enhancements to the regex engine, new hooks into the backend through the <code>B::*</code> modules, the <code>qr//</code> regex quote operator, a large selection of other new core modules, and added support for several more operating systems, including BeOS.<ref name="5005delta">{{Cite web |url=http://perldoc.perl.org/perl5005delta.html |title=perl5005delta - what's new for perl5.005 |access-date=2011-01-21 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=February 3, 2011 |archive-url=https://web.archive.org/web/20110203100249/http://perldoc.perl.org/perl5005delta.html |url-status=live}}</ref>

===2000–2020=== {| class="wikitable floatright" |- ! Major version<ref name="perlhist"/> ! Latest update<ref>{{cite web |url=https://www.cpan.org/src/README.html |title=Perl Source |publisher=cpan.org |access-date=2023-11-26}}</ref> |- | {{Version|o|5.4}} | 1999-04-29 |- | {{Version|o|5.5}} | 2004-02-23 |- | {{Version|o|5.6}} | 2003-11-15 |- | {{Version|o|5.8}} | 2008-12-14 |- | {{Version|o|5.10}} | 2009-08-22 |- | {{Version|o|5.12}} | 2012-11-10 |- | {{Version|o|5.14}} | 2013-03-10 |- | {{Version|o|5.16}} | 2013-03-11 |- | {{Version|o|5.18}} | 2014-10-01 |- | {{Version|o|5.20}} | 2015-09-12 |- | {{Version|o|5.22}} | 2017-07-15 |- | {{Version|o|5.24}} | 2018-04-14 |- | {{Version|o|5.26}} | 2018-11-29 |- | {{Version|o|5.28}} | 2020-06-01 |- | {{Version|o|5.30}} | 2020-06-01 |- | {{Version|o|5.32}} | 2021-01-23 |- | {{Version|o|5.34}} | 2023-11-29 |- | {{Version|o|5.36}} | 2023-11-29 |- | {{Version|o|5.38}} | 2025-04-13 |- | {{Version|co|5.40}} | 2025-04-13 |- | {{Version|c|5.42}} | 2025-07-03  |- | colspan="99" |<small>{{Version|lv|show=011111|}}</small> |}

Perl 5.6 was released on March 22, 2000. Major changes included 64-bit support, Unicode string representation, support for files over 2 GiB, and the "our" keyword.<ref name="56delta">{{cite web |url=http://perldoc.perl.org/perl56delta.html |title=perl56delta - what's new for perl v5.6.0 |access-date=2011-01-21 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=February 2, 2011 |archive-url=https://web.archive.org/web/20110202135358/http://perldoc.perl.org/perl56delta.html |url-status=live}}</ref><ref name="561delta">{{cite web |url=http://perldoc.perl.org/perl561delta.html |title=perl56delta - what's new for perl v5.6.x |access-date=2011-01-21 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=November 18, 2010 |archive-url=https://web.archive.org/web/20101118101544/http://perldoc.perl.org/perl561delta.html |url-status=live}}</ref> When developing Perl 5.6, the decision was made to switch the versioning scheme to one more similar to other open source projects; after 5.005_63, the next version became 5.5.640, with plans for development versions to have odd numbers and stable versions to have even numbers.<ref>{{Cite web |title=Perl {{!}} Definition, History, & Facts {{!}} Britannica |url=https://www.britannica.com/technology/Perl |access-date=2022-06-15 |website=www.britannica.com |language=en}}</ref>

In 2000, Wall put forth a call for suggestions for a new version of Perl from the community. The process resulted in 361 RFC (Request for Comments) documents that were to be used in guiding development of Perl 6. In 2001,<ref>{{cite web |url=http://dev.perl.org/perl6/doc/design/apo/A01.html |title=Apocalypse 1: The Ugly, the Bad, and the Good |access-date=2011-01-08 |last=Wall |first=Larry |archive-date=November 23, 2010 |archive-url=https://web.archive.org/web/20101123182201/http://dev.perl.org/perl6/doc/design/apo/A01.html |url-status=dead}}</ref> work began on the "Apocalypses" for Perl 6, a series of documents meant to summarize the change requests and present the design of the next generation of Perl. They were presented as a digest of the RFCs, rather than a formal document. At this time, Perl 6 existed only as a description of a language.{{Citation needed|date=December 2020}}

Perl 5.8 was first released on July 18, 2002, and further 5.X versions have been released approximately yearly since then. Perl 5.8 improved Unicode support, added a new I/O implementation, added a new thread implementation, improved numeric accuracy, and added several new modules.<ref name="perl58delta">{{cite web |url=http://perldoc.perl.org/perl58delta.html |title=perl58delta - what is new for perl v5.8.0 |access-date=2011-01-21 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=November 21, 2010 |archive-url=https://web.archive.org/web/20101121023149/http://perldoc.perl.org/perl58delta.html |url-status=live}}</ref> As of 2013, this version was still the most popular Perl version and was used by Red Hat Linux 5, SUSE Linux 10, Solaris 10, HP-UX 11.31, and AIX 5.

In 2004, work began on the "Synopses" – documents that originally summarized the Apocalypses, but which became the specification for the Perl 6 language. In February 2005, Audrey Tang began work on Pugs, a Perl 6 interpreter written in Haskell.<ref>{{cite web |url=http://www.perl.com/pub/a/2005/03/03/pugs_interview.html |title=A Plan for Pugs |date=2005-03-03 |publisher=O'Reilly Media |access-date=2011-01-27 |archive-date=September 8, 2012 |archive-url=https://archive.today/20120908200150/http://www.perl.com/pub/2005/03/03/pugs_interview.html |url-status=live}}</ref> This was the first concerted effort toward making Perl 6 a reality. This effort stalled in 2006.<ref>{{cite web |url=http://www.perlmonks.org/?node_id=835936 |title=Re: How to Implement Perl 6 in Ten Years |access-date=2011-01-03 |last=Tang |first=Audrey |date=2010-04-21 |publisher=PerlMonks |archive-date=May 11, 2011 |archive-url=https://web.archive.org/web/20110511190417/http://www.perlmonks.org/?node_id=835936 |url-status=live}}</ref>

The Perl On New Internal Engine (PONIE) project existed from 2003 until 2006. It was to be a bridge between Perl 5 and 6, and an effort to rewrite the Perl 5 interpreter to run on the Perl 6 Parrot virtual machine. The goal was to ensure the future of the millions of lines of Perl 5 code at thousands of companies around the world.<ref>{{citation|last1=Broadwell|first1=Geoff|date=August 8, 2005|title=OSCON 4.4: Inside Ponie, the Bridge from Perl 5 to Perl 6|url=http://www.oreillynet.com/onlamp/blog/2005/08/oscon_44_inside_ponie_the_brid.html|archive-url=https://web.archive.org/web/20120314013450/http://www.oreillynet.com/onlamp/blog/2005/08/oscon_44_inside_ponie_the_brid.html|publisher=O'Reilly ONLamp Blog|access-date=June 27, 2016|archive-date=March 14, 2012|url-status=live}}</ref> The PONIE project ended in 2006 and is no longer being actively developed. Some of the improvements made to the Perl 5 interpreter as part of PONIE were folded into that project.<ref>{{citation|last1=Vincent|first1=Jesse|author1-link=Jesse Vincent|title=Ponie has been put out to pasture|date=August 23, 2006|url=http://news.perlfoundation.org/2006/08/ponie_has_been_put_out_to_past.html|df=mdy-all|archive-url=https://web.archive.org/web/20090627091007/http://news.perlfoundation.org/2006/08/ponie_has_been_put_out_to_past.html|publisher=The Perl Foundation|access-date=January 15, 2019|archive-date=June 27, 2009|url-status=dead}}</ref>

On December 18, 2007, the 20th anniversary of Perl 1.0, Perl 5.10.0 was released. Perl 5.10.0 included notable new features, which brought it closer to Perl 6. These included a switch statement (called "given"/"when"), regular expressions updates, and the ''smart match operator'' (~~).<ref name="5100delta">{{cite web |url=http://perldoc.perl.org/perl5100delta.html |title=perl5100delta - what is new for perl 5.10.0 |access-date=2011-01-08 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=December 21, 2010 |archive-url=https://web.archive.org/web/20101221024004/http://perldoc.perl.org/perl5100delta.html |url-status=live}}</ref><ref name="perlsyn-smart">{{cite web |url=http://perldoc.perl.org/perlsyn.html#Smart-matching-in-detail |title=perlsyn - Perl syntax |access-date=2011-01-21 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=August 26, 2013 |archive-url=https://web.archive.org/web/20130826100652/http://perldoc.perl.org/perlsyn.html#Smart-matching-in-detail |url-status=live}}</ref> Around this same time, development began in earnest on another implementation of Perl 6 known as Rakudo Perl, developed in tandem with the Parrot virtual machine. As of November 2009, Rakudo Perl has had regular monthly releases and now is the most complete implementation of Perl 6.

A major change in the development process of Perl 5 occurred with Perl 5.11; the development community has switched to a monthly release cycle of development releases, with a yearly schedule of stable releases. By that plan, bugfix point releases will follow the stable releases every three months.{{Citation needed|date=December 2020}}

On April 12, 2010, Perl 5.12.0 was released. Notable core enhancements include new <code>package NAME VERSION</code> syntax, the yada yada operator (intended to mark placeholder code that is not yet implemented), implicit {{Not a typo|strictures}}, full Y2038 compliance, regex conversion overloading, DTrace support, and Unicode 5.2.<ref name="5120delta">{{cite web |url=http://perldoc.perl.org/perl5120delta.html |title=perl5120delta - what is new for perl v5.12.0 |access-date=2011-01-08 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=January 4, 2011 |archive-url=https://web.archive.org/web/20110104093548/http://perldoc.perl.org/perl5120delta.html |url-status=live}}</ref>

On May 14, 2011, Perl 5.14 was released with JSON support built-in.<ref>{{cite web|url=https://metacpan.org/pod/distribution/perl/pod/perl5140delta.pod|title=perl5140delta - what is new for perl v5.14.0 - metacpan.org|website=metacpan.org|access-date=July 22, 2017|archive-date=July 25, 2018|archive-url=https://web.archive.org/web/20180725004523/https://metacpan.org/pod/distribution/perl/pod/perl5140delta.pod|url-status=live}}</ref>

On May 20, 2012, Perl 5.16 was released. Notable new features include the ability to specify a given version of Perl that one wishes to emulate, allowing users to upgrade their version of Perl, but still run old scripts that would normally be incompatible.<ref name="5160delta_version">{{cite web |url=https://perldoc.perl.org/perl5160delta |title=perl5160delta - what is new for perl v5.16.0 |access-date=2012-05-21 |website=perldoc.perl.org}}</ref>{{Failed verification|date=June 2022}} Perl 5.16 also updates the core to support Unicode 6.1.<ref name="5160delta_version"/>

On May 18, 2013, Perl 5.18 was released. Notable new features include the new dtrace hooks, lexical subs, more CORE:: subs, overhaul of the hash for security reasons, support for Unicode 6.2.<ref name="5180delta_version">{{cite web |url=https://metacpan.org/pod/release/RJBS/perl-5.18.1/pod/perl5180delta.pod |title=perl5180delta - what is new for perl v5.18.0 - Perl programming language |access-date=2013-10-27 |work=Perl 5 version 18.0 documentation |publisher=metacpan.org |archive-date=October 29, 2013 |archive-url=https://web.archive.org/web/20131029224638/https://metacpan.org/pod/release/RJBS/perl-5.18.1/pod/perl5180delta.pod |url-status=live}}</ref>

On May 27, 2014, Perl 5.20 was released. Notable new features include subroutine signatures, hash slices/new slice syntax, postfix dereferencing (experimental), Unicode 6.3, and a {{Not a typo|rand()}} function using a consistent random number generator.<ref name="5200delta_version">{{cite web |url=https://metacpan.org/source/RJBS/perl-5.20.0/pod/perldelta.pod |title=perl5200delta - what is new for perl v5.20.0 - Perl programming language |access-date=2014-05-27 |work=Perl 5 version 20.0 documentation |publisher=metacpan.org |archive-date=May 27, 2014 |archive-url=https://archive.today/20140527190905/https://metacpan.org/source/RJBS/perl-5.20.0/pod/perldelta.pod |url-status=live}}</ref>

Some observers credit the release of Perl 5.10 with the start of the Modern Perl movement.<ref>[http://www.modernperlbooks.com/mt/2009/07/milestones-in-the-perl-renaissance.html Milestones in the Perl Renaissance – Modern Perl Programming] {{Webarchive|url=https://web.archive.org/web/20121027105918/http://www.modernperlbooks.com/mt/2009/07/milestones-in-the-perl-renaissance.html |date=October 27, 2012}}. Modernperlbooks.com. Retrieved on 2013-07-17.</ref> In particular, this phrase describes a style of development that embraces the use of the CPAN, takes advantage of recent developments in the language, and is rigorous about creating high quality code.<ref>[http://modernperlbooks.com/books/modern_perl/ Preface (Modern Perl 2011-2012)] {{Webarchive|url=https://web.archive.org/web/20120928232457/http://modernperlbooks.com/books/modern_perl/ |date=September 28, 2012}}. Modernperlbooks.com. Retrieved on 2013-07-17.</ref> While the book ''Modern Perl''<ref>[http://onyxneon.com/books/modern_perl/ Modern Perl 2011-2012 edition by chromatic |Onyx Neon Press] {{Webarchive|url=https://web.archive.org/web/20111222045417/http://onyxneon.com/books/modern_perl/ |date=December 22, 2011}}. Onyxneon.com. Retrieved on 2013-07-17.</ref> may be the most visible standard-bearer of this idea, other groups such as the Enlightened Perl Organization<ref>{{cite web|url=http://www.enlightenedperl.org/|title=Enlightened Perl|website=Enlightened Perl|access-date=September 28, 2012|archive-date=February 5, 2014|archive-url=https://web.archive.org/web/20140205015536/http://www.enlightenedperl.org/|url-status=dead}}</ref> have taken up the cause.

In late 2012 and 2013, several projects for alternative implementations for Perl 5 started: Perl5 in Perl6 by the Rakudo Perl team,<ref>{{cite web |url=http://www.yapcna.org/yn2013/talk/4725 |title=YAPC::NA 2013 – June 3–5, Austin, Texas |publisher=Yapcna.org |date=2013-06-04 |access-date=2014-04-11 |archive-url=https://web.archive.org/web/20130622201417/http://www.yapcna.org/yn2013/talk/4725 |archive-date=June 22, 2013 |url-status=dead}}</ref> ''{{Not a typo|moe}}'' by Stevan Little and friends,<ref>{{cite web |last=Little |first=Stevan |url=http://blogs.perl.org/users/stevan_little/2013/02/what-is-moe-a-clarification.html |title=What is Moe (a clarification) | Stevan Little |publisher=Blogs.perl.org |date=2013-02-08 |access-date=2014-04-11 |archive-date=December 19, 2013 |archive-url=https://web.archive.org/web/20131219185710/http://blogs.perl.org/users/stevan_little/2013/02/what-is-moe-a-clarification.html |url-status=live}}</ref> ''{{Not a typo|p2}}''<ref>{{cite web |url=http://perl11.org/p2/ |title=p2 on potion |publisher=Perl11.org |date=2004-02-07 |access-date=2014-04-11 |archive-date=September 24, 2013 |archive-url=https://web.archive.org/web/20130924023845/http://perl11.org/p2/ |url-status=live}}</ref> by the Perl11 team under Reini Urban, ''{{Not a typo|gperl}}'' by {{Not a typo|goccy}},<ref>{{cite web |url=https://github.com/goccy/gperl/ |title=goccy/gperl 路 GitHub |publisher=GitHub.com |access-date=2014-04-11 |archive-date=February 23, 2015 |archive-url=https://web.archive.org/web/20150223170215/https://github.com/goccy/gperl |url-status=live}}</ref> and ''{{Not a typo|rperl}},'' a Kickstarter project led by Will Braswell and affiliated with the Perl11 project.<ref>{{cite web |url=http://rperl.org/faq.html |title=rperl |publisher=RPerl.org |access-date=2014-08-11 |archive-date=October 18, 2014 |archive-url=https://web.archive.org/web/20141018002115/http://rperl.org/faq.html |url-status=live}}</ref>

=== Perl 6 and Raku === {{Main|Raku (programming language)}} thumb|''Camelia'', the logo for the Perl 6 project<ref>{{cite web |url=http://perl6.org/ |title=Perl 6 |access-date=2011-02-27 |publisher=The Perl 6 Project |archive-date=February 21, 2011 |archive-url=https://web.archive.org/web/20110221094526/http://perl6.org/ |url-status=live}}</ref>

At the 2000 Perl Conference, Jon Orwant made a case for a major new language initiative.<ref>{{cite web |url=http://www.nntp.perl.org/group/perl.perl6.meta/2000/10/msg424.html |title=Transcription of Larry's talk |access-date=2011-01-25 |last=Torkington |first=Nathan |publisher=nntp.perl.org |archive-date=May 1, 2011 |archive-url=https://web.archive.org/web/20110501081806/http://www.nntp.perl.org/group/perl.perl6.meta/2000/10/msg424.html |url-status=live}}</ref> This led to a decision to begin work on a redesign of the language, to be called Perl 6. Proposals for new language features were solicited from the Perl community at large, which submitted more than 300 RFCs.<ref>{{Cite web|title=Perl6 - The future of Perl|url=https://www.java-samples.com/showtutorial.php?tutorialid=1443|access-date=2021-05-18|website=www.java-samples.com}}</ref>

Wall spent the next few years digesting the RFCs and synthesizing them into a coherent framework for Perl 6. He presented his design for Perl 6 in a series of documents called "apocalypses" – numbered to correspond to chapters in ''Programming Perl''. {{as of|2011|January}}, the developing specification of Perl 6 was encapsulated in design documents called Synopses – numbered to correspond to Apocalypses.<ref name="syn6">{{cite web |url=http://perlcabal.org/syn/ |title=Official Perl 6 Documentation |access-date=2011-01-25 |publisher=The Perl 6 Project |archive-url=https://web.archive.org/web/20090831103918/http://perlcabal.org/syn/ |archive-date=August 31, 2009 |url-status=dead}}</ref>

Thesis work by Bradley M. Kuhn, overseen by Wall, considered the possible use of the Java virtual machine as a runtime for Perl.<ref>{{cite thesis |last=Kuhn |first=Bradley M. |author-link=Bradley M. Kuhn |title=Considerations on Porting Perl to the Java Virtual Machine |type=MS thesis |publisher=University of Cincinnati |date=January 2001 |url=http://www.ebb.org/bkuhn/writings/technical/thesis/ |access-date=2008-06-28 |archive-date=March 21, 2008 |archive-url=https://web.archive.org/web/20080321164747/http://ebb.org/bkuhn/writings/technical/thesis/ |url-status=live}}</ref> Kuhn's thesis showed this approach to be problematic. In 2001, it was decided that Perl 6 would run on a cross-language virtual machine called Parrot.

In 2005, Audrey Tang created the Pugs project, an implementation of Perl 6 in Haskell. This acted as a test platform for the Perl 6 language (separate from the development of the actual implementation), allowing the language designers to explore. The Pugs project spawned an active Perl/Haskell cross-language community centered around the Libera Chat #raku IRC channel. Many functional programming influences were absorbed by the Perl 6 design team.<ref>{{Cite book|author1=chromatic|author1-link=chromatic (programmer)|url=https://books.google.com/books?id=JUjmsgEACAAJ|title=Modern Perl|date=2015|publisher=Pragmatic Bookshelf|isbn=978-1-68050-088-2|language=en}}</ref>

In 2012, Perl 6 development was centered primarily on two compilers:<ref>{{cite web |url=http://perl6.org/compilers/features |title=Feature comparison of Perl 6 compilers |access-date=March 28, 2012 |archive-url=https://web.archive.org/web/20170811073233/https://perl6.org/compilers/features |archive-date=August 11, 2017 |url-status=dead}}</ref> # Rakudo, an implementation running on the Parrot virtual machine and the Java virtual machine.<ref>{{cite web |last=Worthington |first=Jonathan |title=Rakudo JVM News: More tests, plus Thread and Promise prototypes |url=http://6guts.wordpress.com/2013/07/15/rakudo-jvm-news-more-tests-plus-thread-and-promise-prototypes/ |work=6guts |date=July 15, 2013 |access-date=July 24, 2013 |archive-date=October 5, 2013 |archive-url=https://web.archive.org/web/20131005055559/http://6guts.wordpress.com/2013/07/15/rakudo-jvm-news-more-tests-plus-thread-and-promise-prototypes/ |url-status=live}}</ref> # Niecza, which targets the Common Language Runtime.

In 2013, MoarVM ("Metamodel On A Runtime"), a C language-based virtual machine designed primarily for Rakudo was announced.<ref>{{cite web |last=Worthington |first=Jonathan |title=MoarVM: A virtual machine for NQP and Rakudo |url=http://6guts.wordpress.com/2013/05/31/moarvm-a-virtual-machine-for-nqp-and-rakudo/ |work=6guts |date=May 31, 2013 |access-date=July 24, 2013 |archive-date=July 9, 2013 |archive-url=https://web.archive.org/web/20130709185252/http://6guts.wordpress.com/2013/05/31/moarvm-a-virtual-machine-for-nqp-and-rakudo/ |url-status=live}}</ref>

In October 2019, Perl 6 was renamed to Raku.<ref>{{cite web |url=https://lwn.net/Articles/802329/ |title=rename-lwn |access-date=November 10, 2019 |archive-url=https://web.archive.org/web/20191017155422/https://lwn.net/Articles/802329/ |archive-date=October 17, 2019 |url-status=dead}}</ref>

{{As of|2017}} only the Rakudo implementation and MoarVM are under active development, and other virtual machines, such as the Java Virtual Machine and JavaScript, are supported.<ref>{{cite web |url=https://github.com/rakudo/rakudo/ |title=rakudo/rakudo - GitHub |publisher=GitHub.com |access-date=2013-09-21 |archive-date=July 29, 2017 |archive-url=https://web.archive.org/web/20170729084734/https://github.com/rakudo/rakudo/ |url-status=live}}</ref>

=== Perl 7 ===

In June 2020, Perl 7 was announced as the successor to Perl 5.<ref name="perl7announced">{{cite web |url=https://news.perlfoundation.org/post/perl_7_announced_sawyerx_conference |title=Perl 7 announced at Perl Conference in the Cloud |publisher=perlfoundation.org |date=2020-06-24 |access-date=2020-06-24 |archive-date=June 26, 2020 |archive-url=https://web.archive.org/web/20200626213418/https://news.perlfoundation.org/post/perl_7_announced_sawyerx_conference |url-status=live}}</ref> Perl 7 was to initially be based on Perl 5.32 with a release expected in first half of 2021, and release candidates sooner.<ref name="perl7">{{cite web |url=https://www.perl.com/article/announcing-perl-7/ |title=Announcing Perl 7 |publisher=perl.com |date=2020-06-24 |access-date=2020-06-24 |archive-date=June 24, 2020 |archive-url=https://web.archive.org/web/20200624160531/https://www.perl.com/article/announcing-perl-7/ |url-status=live}}</ref>

This plan was revised in May 2021, without any release timeframe or version of Perl 5 for use as a baseline specified.<ref>{{Cite web|title=Steering Council meeting #019 2021-05-06|url=https://www.nntp.perl.org/group/perl.perl5.porters/2021/05/msg260050.html|last1=Clark|first1=Nicholas|date=2021-05-09|quote=The plan remains that there will be a Perl 7 bump, but not immediately after 5.34.0 is released.{{nbsp}}... We don't think that we can deliver on [Perl 7] in 12 months.|access-date=2021-05-17|website=www.nntp.perl.org|archive-date=2021-05-18|archive-url=https://web.archive.org/web/20210518015233/https://www.nntp.perl.org/group/perl.perl5.porters/2021/05/msg260050.html|url-status=live}}</ref> When Perl 7 would be released, Perl 5 would have gone into long term maintenance. Supported Perl 5 versions however would continue to get important security and bug fixes.<ref>{{cite book |url=https://leanpub.com/preparing_for_perl7 |title=Preparing for Perl 7d |publisher=leanpub.com |date=2020-06-24 |access-date=2020-06-24 |archive-date=June 25, 2020 |archive-url=https://web.archive.org/web/20200625004047/https://leanpub.com/preparing_for_perl7 |url-status=live}}</ref>

Perl 7 was announced on 24 June 2020 at "The Perl Conference in the Cloud" as the successor to Perl 5.<ref name="perl7"/><ref name="perl7announced"/> Based on Perl 5.32, Perl 7 was planned to be backward compatible with modern Perl 5 code; Perl 5 code, without boilerplate (pragma) header needs adding <code>use compat::perl5;</code> to stay compatible, but modern code can drop some of the boilerplate.

The plan to go to Perl 7 brought up more discussion, however, and the Perl Steering Committee canceled it to avoid issues with backward compatibility for scripts that were not written to the pragmas and modules that would become the default in Perl 7. Perl 7 will only come out when the developers add enough features to warrant a major release upgrade.<ref>{{cite web |last1=Perl Steering Council |title=What happened to Perl 7? |url=https://blogs.perl.org/users/psc/2022/05/what-happened-to-perl-7.html |website=blogs.perl.org |access-date=7 July 2022}}</ref>

== Design == {{Main|Perl language structure}}

=== Philosophy ===

According to Wall, Perl has two slogans. The first is "There's more than one way to do it," commonly known as TMTOWTDI, (pronounced ''Tim Toady''). As proponents of this motto argue, this philosophy makes it easy to write concise statements.<ref>{{cite web |last1=Richardson |first1=Marjorie |title=Larry Wall, the Guru of Perl {{!}} Linux Journal |url=https://www.linuxjournal.com/article/3394 |website=www.linuxjournal.com |publisher=Linux Journal |access-date=16 January 2023}}</ref><ref>{{Cite journal |last=Schwartz |first=Alan |date=December 1998 |title=Tutorial: Perl, a psychologically efficient reformatting language |journal=Behavior Research Methods, Instruments, & Computers |language=en |volume=30 |issue=4 |pages=605–609 |doi=10.3758/BF03209477 |s2cid=61028367 |issn=0743-3808|doi-access=free}}</ref><ref>{{Cite journal |last=Gilbert |first=James G. R. |date=March 2002 |title=How to become a programming tadpole |url=http://www.nature.com/articles/nbt0302-221 |journal=Nature Biotechnology |language=en |volume=20 |issue=3 |pages=221 |doi=10.1038/nbt0302-221 |s2cid=38728402 |issn=1087-0156|url-access=subscription }}</ref>

The second slogan is "Easy things should be easy and hard things should be possible".<ref name="programmingperl2"/>

The design of Perl can be understood as a response to three broad trends in the computer industry: falling hardware costs, rising labor costs, and improvements in compiler technology. Many earlier computer languages, such as Fortran and C, aimed to make efficient use of expensive computer hardware. In contrast, Perl was designed so that computer programmers could write programs more quickly and easily.<ref>{{Cite web |date=February 13, 2014 |title=The Fall Of Perl, The Web's Most Promising Language |url=https://www.fastcompany.com/3026446/the-fall-of-perl-the-webs-most-promising-language |website=FastCompany |last1=Myhrvold |first1=Conor }}</ref>

Perl has many features that ease the task of the programmer at the expense of greater CPU and memory requirements. These include automatic memory management; dynamic typing; strings, lists, and hashes; regular expressions; introspection; and an <code>eval()</code> function. Perl follows the theory of "no built-in limits",<ref name="schwartz01"/> an idea similar to the zero one infinity rule.

Wall was trained as a linguist, and the design of Perl is very much informed by linguistic principles. Examples include Huffman coding (common constructions should be short), good end-weighting (the important information should come first), and a large collection of language primitives. Perl favors language constructs that are concise and natural for humans to write, even where they complicate the Perl interpreter.<ref>{{Cite web|last=Wall|first=Larry|title=perl - The Perl 5 language interpreter - Perldoc Browser|url=https://perldoc.perl.org/perl|access-date=2021-06-24|website=perldoc.perl.org}}</ref>

Perl's syntax reflects the idea that "things that are different should look different."<ref name="wall97">{{cite journal |url=http://www.linuxjournal.com/article/2070 |title=Wherefore Art, Thou? |access-date=2011-03-13 |last=Wall |first=Larry |date=1997-03-01 |journal=Linux Journal |archive-date=December 9, 2010 |archive-url=https://web.archive.org/web/20101209021107/http://www.linuxjournal.com/article/2070 |url-status=live}}</ref> For example, scalars, arrays, and hashes have different leading sigils. Array indices and hash keys use different kinds of braces. Strings and regular expressions have different standard delimiters.

There is a broad practical bent to both the Perl language and the community and culture that surround it. The preface to ''Programming Perl'' begins: "Perl is a language for getting your job done."<ref name="programmingperl2"/> One consequence of this is that Perl is not a tidy language. It includes many features, tolerates exceptions to its rules, and employs heuristics to resolve syntactical ambiguities. Because of the forgiving nature of the compiler, bugs can sometimes be hard to find. Perl's function documentation remarks on the variant behavior of built-in functions in list and scalar contexts by saying, "In general, they do what you want, unless you want consistency."<ref name="perlfunc">{{cite web |url=http://perldoc.perl.org/perlfunc.html |title=perlfunc - Perl builtin functions |access-date=2011-01-10 |work=Perl 5 version 12.2 documentation |publisher=perldoc.perl.org |archive-date=January 6, 2011 |archive-url=https://web.archive.org/web/20110106003034/http://perldoc.perl.org/perlfunc.html |url-status=live}}</ref>

=== Features ===

The overall structure of Perl derives broadly from C. Perl is procedural in nature, with variables, expressions, assignment statements, brace-delimited blocks, control structures, and subroutines.<ref>{{Cite book|last=Nagpal|first=D.P.|title=Web Design Technology|publisher=S. Chand|year=2010|isbn=978-8121927635|location=India|pages=700|language=English}}</ref>

Perl also takes features from shell programming. All variables are marked with leading sigils, which allow variables to be interpolated directly into strings. However, unlike the shell, Perl uses sigils on all accesses to variables, and unlike most other programming languages that use sigils, the sigil doesn't denote the type of the variable but the type of the expression. So for example, while an array is denoted by the sigil "@" (for example <code>@arrayname</code>), an individual member of the array is denoted by the scalar sigil "$" (for example <code>$arrayname[3]</code>). Perl also has many built-in functions that provide tools often used in shell programming (although many of these tools are implemented by programs external to the shell) such as sorting, and calling operating system facilities.{{Citation needed|date=December 2020}}

Perl takes hashes ("associative arrays") from AWK and regular expressions from sed. These simplify many parsing, text-handling, and data-management tasks. Shared with Lisp is the implicit return of the last value in a block, and all statements are also expressions which can be used in larger expressions themselves.{{Citation needed|date=December 2020}}

Perl 5 added features that support complex data structures, first-class functions (that is, closures as values), and an object-oriented programming model. These include references, packages, class-based method dispatch, and lexically scoped variables, along with compiler directives (for example, the <code>strict</code> pragma). A major additional feature introduced with Perl 5 was the ability to package code as reusable modules. Wall later stated that "The whole intent of Perl 5's module system was to encourage the growth of Perl culture rather than the Perl core."<ref>{{cite newsgroup |title=title unknown |date=1997-05-10 |message-id=199705101952.MAA00756@wall.org}}{{Dead link|date=November 2014}}</ref>

All versions of Perl do automatic data-typing and automatic memory management. The interpreter knows the type and storage requirements of every data object in the program; it allocates and frees storage for them as necessary using reference counting (so it cannot deallocate circular data structures without manual intervention). Legal type conversions – for example, conversions from number to string – are done automatically at run time; illegal type conversions are fatal errors.{{Citation needed|date=December 2020}}

=== Syntax ===

Perl has been referred to as "line noise" and a "write-only language" by its critics. Randal L. Schwartz in the first edition of the book ''Learning Perl'',<ref>{{cite journal |title=Developer Update|volume=2 |journal=Dr. Dobb's Developer Update |publisher=Miller-Freeman |year=1995 |page=15}}</ref> in the first chapter states: "Yes, sometimes Perl looks like line noise to the uninitiated, but to the seasoned Perl programmer, it looks like checksummed line noise with a mission in life."<ref name="LP">{{cite book |title=Learning Perl |last=Schwartz |first=Randal L. |author-link=Randal L. Schwartz |publisher=O'Reilly & Associates |year=1993 |title-link=Learning Perl |bibcode=1993lepe.book.....S}}</ref> He also stated that the accusation that Perl is a write-only language could be avoided by coding with "proper care".<ref name="LP"/> The Perl overview document ''{{Not a typo|perlintro}}'' states that the names of built-in "magic" scalar variables "look like punctuation or line noise".<ref>{{cite web |url=http://perldoc.perl.org/perlintro.html |title=perlintro |work=Perl 5 version 18.0 documentation |publisher=Perl 5 Porters and perldoc.perl.org |access-date=2013-06-30 |archive-url=https://web.archive.org/web/20110109121845/http://perldoc.perl.org/perlintro.html |archive-date=January 9, 2011 |url-status=dead}}</ref> However, the English module provides both long and short English alternatives. ''{{Not a typo|perlstyle}}'' document states that line noise in regular expressions could be mitigated using the <code>/x</code> modifier to add whitespace.<ref>{{cite web |url=http://perldoc.perl.org/perlstyle.html |title=perlstyle |work=Perl 5 version 18.0 documentation |publisher=Perl 5 Porters and perldoc.perl.org |access-date=2013-06-30 |archive-url=https://web.archive.org/web/20130626010707/http://perldoc.perl.org/perlstyle.html |archive-date=June 26, 2013 |url-status=dead}}</ref>

According to the ''Perl 6 FAQ'',<ref name="P6FAQ">{{cite web |url=http://www.perl6.org/archive/faq.html |title=Perl 6 FAQ |publisher=Perl 6 Project |access-date=2013-06-30 |archive-date=July 1, 2013 |archive-url=https://web.archive.org/web/20130701183900/http://www.perl6.org/archive/faq.html |url-status=dead}}</ref> Perl 6 was designed to mitigate "the usual suspects" that elicit the "line noise" claim from Perl 5 critics, including the removal of "the majority of the punctuation variables" and the sanitization of the regex syntax. The ''Perl 6 FAQ'' also states that what is sometimes referred to as Perl's line noise is "the actual syntax of the language" just as gerunds and prepositions are a part of the English language.<ref name="P6FAQ"/> In a December 2012 blog posting, despite claiming that "Rakudo Perl 6 has failed and will continue to fail unless it gets some adult supervision", chromatic stated that the design of Perl 6 has a "well-defined grammar", an "improved type system, a unified object system with an intelligent metamodel, metaoperators, and a clearer system of context that provides for such niceties as pervasive laziness."<ref name="chromatic-blog">{{cite web |url=http://www.modernperlbooks.com/mt/2012/12/the-implementation-of-perl-5-versus-perl-6.html |title=The Implementation of Perl 5 versus Perl 6 |author1=chromatic |author1-link=chromatic (programmer) |date=2012-12-31 |access-date=2013-06-30 |archive-date=July 29, 2013 |archive-url=https://web.archive.org/web/20130729214209/http://www.modernperlbooks.com/mt/2012/12/the-implementation-of-perl-5-versus-perl-6.html |url-status=live}}</ref> He also stated that "Perl 6 has a coherence and a consistency that Perl 5 lacks."<ref name="chromatic-blog"/>

In Perl, one could write the "Hello, World!" program as:

<syntaxhighlight lang="perl"> print "Hello, World!\n"; </syntaxhighlight>

Here is a more complex Perl program, that counts down seconds from a given starting value:

<syntaxhighlight lang="perl"> #!/usr/bin/env perl use strict; use warnings;

my ( $remaining, $total );

$remaining=$total=shift(@ARGV);

STDOUT->autoflush(1);

while ( $remaining ) { printf ( "Remaining %s/%s \r", $remaining--, $total ); sleep 1; }

print "\n"; </syntaxhighlight>

To run the code above, store it in a file named <code>counter.pl</code>, and then execute it.

<syntaxhighlight lang="console">$ perl counter.pl 42</syntaxhighlight>

The Perl interpreter can also be used for one-off scripts on the command line. The following example (as invoked from an sh-compatible shell, such as Bash) translates the string "Bob" in all files ending with .txt in the current directory to "Robert":

<syntaxhighlight lang="console">$ perl -i.bak -lp -e 's/Bob/Robert/g' *.txt</syntaxhighlight>

=== Implementation ===

No written specification or standard for the Perl language exists for Perl versions through Perl 5, and there are no plans to create one for the current version of Perl. There has been only one implementation of the interpreter, and the language has evolved along with it. That interpreter, together with its functional tests, stands as a ''de facto'' specification of the language. Perl 6, however, started with a specification,<ref>{{cite web |url=http://www.perl6.org/specification |title=Perl 6 Specification |access-date=2011-01-27 |publisher=The Perl 6 Project |archive-date=December 2, 2009 |archive-url=https://web.archive.org/web/20091202073507/http://www.perl6.org/specification/ |url-status=live}}</ref> and several projects<ref>{{cite web |url=http://www.perl6.org/compilers/ |title=Perl 6 Compilers |access-date=2011-01-27 |publisher=The Perl 6 Project |archive-date=December 2, 2009 |archive-url=https://web.archive.org/web/20091202073302/http://www.perl6.org/compilers/ |url-status=live}}</ref> aim to implement some or all of the specification.{{Citation needed|date=December 2020}}

Perl is implemented as a core interpreter, written in C, together with a large collection of modules, written in Perl and C. {{As of|2010}}, the interpreter is 150,000 lines of C code and compiles to a 1 MB executable on typical machine architectures. Alternatively, the interpreter can be compiled to a link library and embedded in other programs. There are nearly 500 modules in the distribution, comprising 200,000 lines of Perl and an additional 350,000 lines of C code (much of the C code in the modules consists of character encoding tables).{{Citation needed|date=December 2020}}

The interpreter has an object-oriented architecture. All of the elements of the Perl language—scalars, arrays, hashes, coderefs, file handles—are represented in the interpreter by C structs. Operations on these structs are defined by a large collection of macros, typedefs, and functions; these constitute the Perl C API. The Perl API can be bewildering to the uninitiated, but its entry points follow a consistent naming scheme, which provides guidance to those who use it.{{Citation needed|date=December 2020}}

The life of a Perl interpreter divides broadly into a compile phase and a run phase.<ref>A description of the Perl 5 interpreter can be found in ''Programming Perl'', 3rd Ed., chapter 18. See particularly page 467, which carefully distinguishes run phase and compile phase from run time and compile time. Perl "time" and "phase" are often confused.</ref> According to Aluín et al., "Perl cannot be parsed by a straight Lex/Yacc lexer/parser combination. Instead, the interpreter implements its own lexer, which coordinates with a modified GNU bison parser to resolve ambiguities in the language."<ref>{{Cite book |last1=Abuin |first1=Jose M. |last2=Pichel |first2=Juan C. |last3=Pena |first3=Tomas F. |last4=Gamallo |first4=Pablo |last5=Garcia |first5=Marcos |chapter=Perldoop: Efficient execution of Perl scripts on Hadoop clusters |date=2014 |title=2014 IEEE International Conference on Big Data (Big Data) |publisher=IEEE |pages=766–771 |doi=10.1109/BigData.2014.7004303 |isbn=978-1-4799-5666-1}}</ref>

Most of what happens in Perl's compile phase is compilation, and most of what happens in Perl's run phase is execution, but there are significant exceptions. Perl makes important use of its capability to execute Perl code during the compile phase. Perl will also delay compilation into the run phase. The terms that indicate the kind of processing that is actually occurring at any moment are ''compile time'' and ''run time''. Perl is in compile time at most points during the compile phase, but compile time may also be entered during the run phase. The compile time for code in a string argument passed to the <code>eval</code> built-in occurs during the run phase. Perl is often in run time during the compile phase and spends most of the run phase in run time. Code in <code>BEGIN</code> blocks executes at run time but in the compile phase.

At compile time, the interpreter parses Perl code into a syntax tree. At run time, it executes the program by walking the tree. Text is parsed only once, and the syntax tree is subject to optimization before it is executed, so that execution is relatively efficient. Compile-time optimizations on the syntax tree include constant folding and context propagation, but peephole optimization is also performed.<ref>{{Cite web|title=perlguts - Introduction to the Perl API - Perldoc Browser|url=https://perldoc.perl.org/perlguts#Compile-pass-3:-peephole-optimization|access-date=2022-01-24|website=perldoc.perl.org}}</ref>

Perl has a Turing-complete grammar because parsing can be affected by run-time code executed during the compile phase.<ref>{{cite web |last=Schwartz |first=Randal |author-link=Randal L. Schwartz |title=On Parsing Perl |url=http://www.perlmonks.org/index.pl?node_id=44722 |access-date=2007-01-03 |archive-date=September 27, 2007 |archive-url=https://web.archive.org/web/20070927000827/http://www.perlmonks.org/index.pl?node_id=44722 |url-status=live}}</ref> The code cannot be parsed by a straight Lex/Yacc lexer/parser. To resolve ambiguities in the language the interpreter must implement its own lexer to coordinate with a modified GNU bison parser.<ref>{{Cite book |last1=Abuin |first1=Jose M. |last2=Pichel |first2=Juan C. |last3=Pena |first3=Tomas F. |last4=Gamallo |first4=Pablo |last5=Garcia |first5=Marcos |chapter=Perldoop: Efficient execution of Perl scripts on Hadoop clusters |date=2014 |title=2014 IEEE International Conference on Big Data (Big Data) |publisher=IEEE |pages=766–771 |doi=10.1109/BigData.2014.7004303 |isbn=978-1-4799-5666-1}}</ref>

It is often said that "Only perl can parse Perl",<ref>{{cite web |url=ftp://ftp.ora.com/pub/labs/tpj/tpj2.pdf |title=The Perl Journal #19/9.26 |access-date=2011-02-04 |archive-url=https://web.archive.org/web/20200227002839/ftp://ftp.ora.com/pub/labs/tpj/tpj2.pdf |archive-date=2020-02-27 |url-status=dead |publisher=O'Reilly Media }}</ref> meaning that only the Perl interpreter (''<code>perl</code>'') can parse the Perl language (''Perl''), but even this is not, in general, true. Because the Perl interpreter can simulate a Turing machine during its compile phase, it would need to decide the halting problem in order to complete parsing in every case. It is a longstanding result that the halting problem is undecidable, and therefore not even Perl can always parse Perl. Perl makes the unusual choice of giving the user access to its full programming power in its own compile phase. The cost in terms of theoretical purity is high, but practical inconvenience seems to be rare.<ref>{{cite web |url=http://blogs.perl.org/users/jeffrey_kegler/2011/10/perl-and-parsing-11-are-all-perl-programs-parseable.html |title=Perl and Parsing 11: Are all Perl programs parseable? |last=Kegler |first=Jeffrey |date=October 7, 2011 |access-date=October 25, 2022 |quote=... we seem to be giving up absolutely nothing. Nobody has ever been able to show a practical downside}}</ref>

Other programs that undertake to parse Perl, such as source-code analyzers and auto-indenters, have to contend not only with ambiguous syntactic constructs but also with the undecidability of Perl parsing in the general case. Adam Kennedy's PPI project focused on parsing Perl code as a document (retaining its integrity as a document), instead of parsing Perl as executable code (that not even Perl itself can always do). It was Kennedy who first conjectured that "parsing Perl suffers from the 'halting problem',"<ref>{{cite web |url=https://metacpan.org/module/PPI |title=PPI—Parse, Analyze and Manipulate Perl (without perl) |last1=Kennedy |first1=Adam |year=2006 |publisher=CPAN |access-date=September 16, 2013 |archive-date=September 3, 2013 |archive-url=https://web.archive.org/web/20130903091241/https://metacpan.org/module/PPI |url-status=live}}</ref> which was later proved.<ref>{{cite journal |title=Rice's Theorem |journal=The Perl Review |volume=4 |issue=3 |pages=23–29 |date=Summer 2008}} and {{cite journal |title=Perl is Undecidable |journal=The Perl Review |volume=5 |pages=7–11 |date=Fall 2008}}, available online at {{cite web |url=http://www.jeffreykegler.com/Home/perl-and-undecidability |title=Perl and Undecidability |last1=Kegler|first1=Jeffrey |access-date=January 4, 2009 |archive-date=August 17, 2009 |archive-url=https://web.archive.org/web/20090817183115/http://www.jeffreykegler.com/Home/perl-and-undecidability |url-status=live}}</ref>

Perl is distributed with over 250,000 functional tests for core Perl language and over 250,000 functional tests for core modules. These run as part of the normal build process and extensively exercise the interpreter and its core modules. Perl developers rely on the functional tests to ensure that changes to the interpreter do not introduce software bugs; further, Perl users who see that the interpreter passes its functional tests on their system can have a high degree of confidence that it is working properly.{{Citation needed|date=December 2020}}

== Ports ==

Perl is dual licensed under both the Artistic License 1.0<ref name="artistic-1.0">{{cite web|url=http://dev.perl.org/licenses/artistic.html|title=The "Artistic License" - dev.perl.org|website=dev.perl.org|access-date=June 24, 2016|archive-date=July 24, 2018|archive-url=https://web.archive.org/web/20180724213601/http://dev.perl.org/licenses/artistic.html|url-status=live}}</ref><ref name="artistic-1.0-git">[http://perl5.git.perl.org/perl.git/blob/HEAD:/Artistic Artistic] {{Webarchive|url=https://web.archive.org/web/20180725033309/http://perl5.git.perl.org/perl.git/blob/HEAD:/Artistic |date=July 25, 2018}} - file on the Perl 5 git repository</ref> and the GNU General Public License.<ref name="licensing">{{cite web |url=http://dev.perl.org/licenses |title=Perl Licensing |access-date=2011-01-08 |publisher=dev.perl.org |archive-date=January 22, 2011 |archive-url=https://web.archive.org/web/20110122175123/http://dev.perl.org/licenses/ |url-status=live}}</ref> Distributions are available for most operating systems. It is particularly prevalent on Unix and Unix-like systems, but it has been ported to most modern (and many obsolete) platforms. With only six{{citation needed|date=November 2017}} reported exceptions, Perl can be compiled from source code on all POSIX-compliant, or otherwise-Unix-compatible, platforms.<ref name="cpanports">{{cite web |url=http://www.cpan.org/ports/ |title=Perl Ports (Binary Distributions) |publisher=CPAN.org |last1=Hietaniemi |first1=Jarkko |year=1998 |access-date=April 16, 2006 |archive-date=April 18, 2006 |archive-url=https://web.archive.org/web/20060418115903/http://www.cpan.org/ports/ |url-status=live}}</ref>

Because of unusual changes required for the classic Mac OS environment, a special port called MacPerl was shipped independently.<ref name="macperl">{{cite web |url=http://www.macperl.com/ |title=The MacPerl Pages |year=1997 |publisher=Prime Time Freeware |access-date=January 18, 2006 |archive-date=January 18, 2006 |archive-url=https://web.archive.org/web/20060118125208/http://www.macperl.com/ |url-status=live}}</ref>

The Comprehensive Perl Archive Network carries a complete list of supported platforms with links to the distributions available on each.<ref>{{cite web |url=http://www.cpan.org/ports/ |title=Perl Ports (Binary Distributions) |access-date=2011-01-27 |publisher=CPAN |archive-date=April 18, 2006 |archive-url=https://web.archive.org/web/20060418115903/http://www.cpan.org/ports/ |url-status=live}}</ref> CPAN is also the source for publicly available Perl modules that are not part of the core Perl distribution.{{Citation needed|date=December 2020}}

ActivePerl is a closed-source distribution from ActiveState that has regular releases that track the core Perl releases.<ref name="activestate">{{cite web |url=http://www.activestate.com/activeperl |title=ActivePerl is Perl for Windows, Mac, Linux, AIX, HP-UX & Solaris |access-date=2011-01-09 |publisher=ActiveState Software |archive-url=https://web.archive.org/web/20160331201814/http://www.activestate.com/activeperl |archive-date=March 31, 2016 |url-status=dead}}</ref> The distribution previously included the Perl package manager (PPM),<ref name="activestateppm">{{cite web |url=http://docs.activestate.com/activeperl/5.12/faq/ActivePerl-faq2.html |title=Using PPM |access-date=2011-01-09 |publisher=ActiveState Software |archive-date=August 27, 2010 |archive-url=https://web.archive.org/web/20100827110749/http://docs.activestate.com/activeperl/5.12/faq/ActivePerl-faq2.html |url-status=live}}</ref> a popular tool for installing, removing, upgrading, and managing the use of common Perl modules; however, this tool was discontinued as of ActivePerl 5.28.<ref>{{Cite news |last1=Crane |first1=Dana |date=July 23, 2019 |url=https://www.activestate.com/blog/goodbye-ppm-hello-state-tool/ |title=Goodbye PPM, Hello State Tool |website=Activestate.com |access-date=April 16, 2020 |archive-date=July 28, 2020 |archive-url=https://web.archive.org/web/20200728080612/https://www.activestate.com/blog/goodbye-ppm-hello-state-tool/ |url-status=live}}</ref> Included also is PerlScript, a Windows Script Host (WSH) engine implementing the Perl language. Visual Perl is an ActiveState tool that adds Perl to the Visual Studio .NET development suite. A VBScript-to-Perl converter, a Perl compiler for Windows, and converters of AWK and sed to Perl have also been produced by this company and included on the ''ActiveState CD for Windows'', which includes all of their distributions plus the Komodo IDE and all but the first on the Unix–Linux–POSIX variant thereof in 2002 and afterward.{{citation needed|date=April 2025}}

== Performance ==

The Computer Language Benchmarks Game compares the performance of implementations of typical programming problems in several programming languages.<ref>{{cite web |url=http://alioth.debian.org/projects/benchmarksgame/ |title=Alioth: The Computer Language Benchmarks Game: Project Info |access-date=2011-01-13 |publisher=Alioth |archive-url=https://web.archive.org/web/20130325192723/https://alioth.debian.org/projects/benchmarksgame/ |archive-date=March 25, 2013 |url-status=dead |df=mdy-all}}</ref> The submitted Perl implementations typically perform toward the high end of the memory-usage spectrum and give varied speed results. Perl's performance in the benchmarks game is typical for interpreted languages.<ref>{{cite web |url=http://benchmarksgame.alioth.debian.org/u32/which-programs-are-fastest.php?v8=on&lua=on&jruby=on&php=on&python3=on&yarv=on&perl=on |archive-url=https://web.archive.org/web/20130517145336/http://benchmarksgame.alioth.debian.org/u32/which-programs-are-fastest.php?v8=on&lua=on&jruby=on&php=on&python3=on&yarv=on&perl=on |url-status=dead |archive-date=2013-05-17 |title=Which programs are fastest? |access-date=2011-01-13 |work=Computer Language Benchmarks Game |publisher=Alioth}}</ref>

Large Perl programs start more slowly than similar programs in compiled languages because Perl has to compile the source every time it runs. In a talk at the YAPC::Europe 2005 conference and subsequent article "A Timely Start", Jean-Louis Leroy found that his Perl programs took much longer to run than expected because the perl interpreter spent significant time finding modules within his over-large include path.<ref>{{cite web |url=http://www.perl.com/pub/a/2005/12/21/a_timely_start.html |title=A Timely Start |last1=Leroy |first1=Jean-Louis |date=2005-12-01 |publisher=O'Reilly |access-date=May 22, 2006 |archive-date=June 13, 2006 |archive-url=https://web.archive.org/web/20060613025623/http://www.perl.com/pub/a/2005/12/21/a_timely_start.html |url-status=live}}</ref> Unlike Java, Python, and Ruby, Perl has only experimental support for pre-compiling.<ref>{{cite web |url=https://metacpan.org/module/NWCLARK/perl-5.8.8/ext/B/B/Bytecode.pm#KNOWN-BUGS |title=B::Bytecode Perl compiler's bytecode backend |author1=Beattie, Malcolm |author2=Enache Adrian |name-list-style=amp |year=2003 |publisher=CPAN |access-date=September 16, 2013 |archive-date=March 30, 2021 |archive-url=https://web.archive.org/web/20210330011632/https://metacpan.org/pod/release/NWCLARK/perl-5.8.8/ext/B/B/Bytecode.pm#KNOWN-BUGS |url-status=dead}}</ref> Therefore, Perl programs pay this overhead penalty on every execution. The run phase of typical programs is long enough that amortized startup time is not substantial, but benchmarks that measure very short execution times are likely to be skewed due to this overhead.<ref>{{Cite book|last1=Schwartz|first1=Randal|url=https://books.google.com/books?id=va1PSgaO4xIC&q=Therefore,+Perl+programs+pay+this+overhead+penalty+on+every+execution.+The+run+phase+of+typical+programs+is+long+enough+that+amortized+startup+time+is+not+substantial,+but+benchmarks+that+measure+very+short+execution+times+are+likely+to+be+skewed+due+to+this+overhead.|title=Learning Perl|last2=foy|first2=brian|last3=Phoenix|first3=Tom|date=2011-06-23|publisher=O'Reilly Media, Inc.|isbn=978-1-4493-0358-7|language=en}}</ref>

A number of tools have been introduced to improve this situation. The first such tool was Apache's mod_perl, which sought to address one of the most-common reasons that small Perl programs were invoked rapidly: CGI Web development. ActivePerl, via Microsoft ISAPI, provides similar performance improvements.<ref>{{Cite book|last1=Stein|first1=Lincoln|url=https://books.google.com/books?id=qyzTI_eAeHUC&q=A+number+of+tools+have+been+introduced+to+improve+this+situation.+The+first+such+tool+was+Apache's+mod+perl,+which+sought+to+address+one+of+the+most-common+reasons+that+small+Perl+programs+were+invoked+rapidly:+CGI+Web+development.+ActivePerl,+via+Microsoft+ISAPI,+provides+similar+performance+improvements.|title=Writing Apache Modules with Perl and C: The Apache API and Mod_perl|last2=MacEachern|first2=Doug|date=1999|publisher=O'Reilly Media, Inc.|isbn=978-1-56592-567-0|language=en}}</ref>

Once Perl code is compiled, there is additional overhead during the execution phase that typically isn't present for programs written in compiled languages such as C or C++. Examples of such overhead include bytecode interpretation, reference-counting memory management, and dynamic type-checking.<ref>{{Cite book|last1=Bekman|first1=Stas|url=https://books.google.com/books?id=UDabAgAAQBAJ&q=Once+Perl+code+is+compiled,+there+is+additional+overhead+during+the+execution+phase+that+typically+isn't+present+for+programs+written+in+compiled+languages+such+as+C+or+C++.+Examples+of+such+overhead+include+bytecode+interpretation,+reference-counting+memory+management,+and+dynamic+type-checking.|title=Practical Mod_perl|last2=Cholet|first2=Eric|date=2003|publisher=O'Reilly Media, Inc.|isbn=978-0-596-00227-5|language=en}}</ref>

The most critical routines can be written in other languages (such as C), which can be connected to Perl via simple Inline modules or the more complex, but flexible, XS mechanism.<ref>{{cite web |url=https://metacpan.org/module/Inline |title=Inline - metacpan.org |access-date=2011-01-26 |last=Ingerson |first=Brian |publisher=CPAN |url-status=dead |archive-url=https://web.archive.org/web/20130613163723/https://metacpan.org/module/Inline |archive-date=June 13, 2013}}</ref>

== Applications ==

Perl has many and varied applications, compounded by the availability of many standard and third-party modules.

Perl has chiefly been used to write CGI scripts: large projects written in Perl include cPanel, Slash, Bugzilla, RT, TWiki, and Movable Type; high-traffic websites that use Perl extensively include Priceline.com, Craigslist,<ref>{{cite book |last1=Gilmore |first1=W. J. |title=Beginning PHP and MySQL: From Novice to Professional, Fourth Edition |year=2010 |url=https://archive.org/details/beginningphpmysq00gilm_240 |url-access=limited |publisher=Apress |page=[https://archive.org/details/beginningphpmysq00gilm_240/page/n519 484] |isbn=978-1-4302-3114-1}}</ref> IMDb,<ref>{{cite web |title=IMDb Helpdesk: What software/hardware are you using to run the site? |website=Internet Movie Database |url=https://www.imdb.com/help/search?domain=helpdesk_faq&index=1&file=techinfo |access-date=2011-02-12 |archive-date=March 9, 2017 |archive-url=https://web.archive.org/web/20170309083513/http://www.imdb.com/help/search?domain=helpdesk_faq&index=1&file=techinfo |url-status=live}}</ref> LiveJournal, DuckDuckGo,<ref>DuckDuckGo handles a large amount of search queries at 4.5 million queries per day . https://duckduckgo.com/traffic.html {{Webarchive|url=http://webarchive.loc.gov/all/20120215210604/https://duckduckgo.com/traffic.html |date=February 15, 2012}}</ref><ref>DuckDuckGo uses Perl https://web.archive.org/web/20101231135106/http://www.gabrielweinberg.com/blog/2009/03/duck-duck-go-architecture.html</ref> Slashdot and Ticketmaster.  It is also an optional component of the popular LAMP technology stack for Web development, in lieu of PHP or Python. Perl is used extensively as a system programming language in the Debian Linux distribution.<ref>{{cite web|url=https://wiki.debian.org/PerlFAQ|title=Perl FAQ|quote=Perl is used quite extensively in Debian. Not only are some core functions written in Perl, but there are over 700 packages in unstable that have perl in their name (Mar 2004).|access-date=August 6, 2019|archive-date=August 6, 2019|archive-url=https://web.archive.org/web/20190806111259/https://wiki.debian.org/PerlFAQ|url-status=live}}</ref>

Perl is often used as a glue language, tying together systems and interfaces that were not specifically designed to interoperate, and for "data munging",<ref>{{cite web |url=http://books.perl.org/book/95 |title=Perl Books - Book: Data Munging with Perl |work=Perl.org |access-date=December 30, 2010 |archive-date=September 7, 2011 |archive-url=https://web.archive.org/web/20110907020511/http://books.perl.org/book/95 |url-status=live}}</ref> that is, converting or processing large amounts of data for tasks such as creating reports. These strengths are linked intimately. The combination makes Perl a popular all-purpose language for system administrators, particularly because short programs, often called "one-liner programs", can be entered and run on a single command line.{{Citation needed|date=December 2020}}

Perl code can be made portable across Windows and Unix; such code is often used by suppliers of software (both commercial off-the-shelf (COTS) and bespoke) to simplify packaging and maintenance of software build- and deployment-scripts.<ref>{{Cite web |title=perlport - Writing portable Perl - Perldoc Browser |url=https://perldoc.perl.org/perlport |access-date=2026-05-29 |website=perldoc.perl.org}}</ref>

Perl/Tk and wxPerl are commonly used to add graphical user interfaces to Perl scripts.

Perl's text-handling capabilities can be used for generating SQL queries; arrays, hashes, and automatic memory management make it easy to collect and process the returned data. For example, in Tim Bunce's Perl DBI application programming interface (API), the arguments to the API can be the text of SQL queries; thus it is possible to program in multiple languages at the same time (e.g., for generating a Web page using HTML, JavaScript, and SQL in a here document). The use of Perl variable interpolation to programmatically customize each of the SQL queries, and the specification of Perl arrays or hashes as the structures to programmatically hold the resulting data sets from each SQL query, allows a high-level mechanism for handling large amounts of data for post-processing by a Perl subprogram.<ref>{{cite book |last=Descartes |first=Alligator |title=Programming the Perl DBI : [database programming with Perl] |year=2000 |publisher=O'Reilly |location=Beijing [u.a.] |isbn=978-1-56592-699-8 |edition=1 |author2=Bunce, Tim |url=https://archive.org/details/programmingperld00desc}}</ref> In early versions of Perl, database interfaces were created by relinking the interpreter with a client-side database library. This was sufficiently difficult that it was done for only a few of the most-important and most widely used databases, and it restricted the resulting <code>perl</code> executable to using just one database interface at a time.<ref>{{Cite web|title=Perl Programming - Principles of Programming Languages|url=https://sites.google.com/a/principlesofprogram.com/www/perl|access-date=2021-05-18|website=sites.google.com|archive-date=October 8, 2020|archive-url=https://web.archive.org/web/20201008130113/https://sites.google.com/a/principlesofprogram.com/www/perl|url-status=dead}}</ref>

In Perl 5, database interfaces are implemented by Perl DBI modules. The DBI (Database Interface) module presents a single, database-independent interface to Perl applications, while the DBD (Database Driver) modules handle the details of accessing some 50 different databases; there are DBD drivers for most ANSI SQL databases.<ref>{{Cite book|last1=Bunce|first1=Tim|url=https://books.google.com/books?id=WfoOrfuwcb8C&q=The+DBI+(Database+Interface)+module+presents+a+single,+database-independent+interface+to+Perl+applications,+while+the+DBD+(Database+Driver)+modules+handle+the+details+of+accessing+some+50+different+databases;+there+are+DBD+drivers+for+most+ANSI+SQL+databases|title=Programming the Perl DBI: Database programming with Perl|last2=Descartes|first2=Alligator|date=2000-02-04|publisher=O'Reilly Media, Inc.|isbn=978-1-4493-1536-8|language=en}}</ref>

DBI provides caching for database handles and queries, which can greatly improve performance in long-lived execution environments such as mod_perl,<ref>{{cite web |last=Bekman |first=Stas |title=Efficient Work with Databases under mod_perl |url=http://perl.apache.org/docs/1.0/guide/performance.html#Efficient_Work_with_Databases_under_mod_perl |access-date=2007-09-01 |archive-date=August 22, 2007 |archive-url=https://web.archive.org/web/20070822162513/http://perl.apache.org/docs/1.0/guide/performance.html#Efficient_Work_with_Databases_under_mod_perl |url-status=live}}</ref> helping high-volume systems avert load spikes as in the Slashdot effect.<ref>{{Cite book|last=Pachev|first=Sasha|url=https://books.google.com/books?id=vz6PcTdo8VUC&q=DBI+provides+caching+for+database+handles+and+queries,+which+can+greatly+improve+performance+in+long-lived+execution+environments+such+as+mod+perl,%5B100%5D+helping+high-volume+systems+avert+load+spikes+as+in+the+Slashdot+effect|title=Understanding MySQL Internals: Discovering and Improving a Great Database|date=2007-04-10|publisher=O'Reilly Media, Inc.|isbn=978-0-596-55280-0|language=en}}</ref>

In modern Perl applications, especially those written using web frameworks such as Catalyst, the DBI module is often used indirectly via object–relational mappers such as DBIx::Class, Class::DBI<ref>{{Cite web|url=https://metacpan.org/pod/Class::DBI|title=Class::DBI - Simple Database Abstraction - metacpan.org|website=metacpan.org|access-date=2020-04-08|archive-date=August 6, 2020|archive-url=https://web.archive.org/web/20200806100410/https://metacpan.org/pod/Class::DBI|url-status=live}}</ref> or Rose::DB::Object<ref>{{Cite web|url=https://metacpan.org/pod/Rose::DB::Object|title=Rose::DB::Object - Extensible, high performance object-relational mapper (ORM). - metacpan.org|website=metacpan.org|access-date=2020-04-08|archive-date=August 6, 2020|archive-url=https://web.archive.org/web/20200806085143/https://metacpan.org/pod/Rose::DB::Object|url-status=live}}</ref> that generate SQL queries and handle data transparently to the application author.<ref>{{Cite web|title=T sql querying developer reference|url=http://pdfpremiumfree.com/download/t-sql-querying-developer-reference-pdf/|access-date=2021-05-18|website=pdfpremiumfree.com|language=en}}</ref>

== Community ==

Perl's culture and community has developed alongside the language itself. Usenet was the first public venue in which Perl was introduced, but over the course of its evolution, Perl's community was shaped by the growth of broadening Internet-based services including the introduction of the World Wide Web. The community that surrounds Perl was, in fact, the topic of Wall's first "State of the Onion" talk.<ref>{{cite web |url=http://grnlight.net/index.php/programming-articles/100-perl-culture |title=Perl Culture (AKA the first State of the Onion) |first=Larry |last=Wall |author-link=Larry Wall |date=2014-05-22 |access-date=May 22, 2014 |archive-date=May 22, 2014 |archive-url=https://web.archive.org/web/20140522141559/http://grnlight.net/index.php/programming-articles/100-perl-culture |url-status=usurped}}</ref>

State of the Onion is the name for Wall's yearly keynote-style summaries on the progress of Perl and its community. They are characterized by his hallmark humor, employing references to Perl's culture, the wider hacker culture, Wall's linguistic background, sometimes his family life, and occasionally even his Christian background.<ref>{{cite web |title=2nd State of the Onion |last1=Wall |first1=Larry |author1-link=Larry Wall |url=http://www.wall.org/~larry/onion/onion.html |access-date=2012-10-12 |archive-date=July 17, 2012 |archive-url=https://web.archive.org/web/20120717014443/http://www.wall.org/~larry/onion/onion.html |url-status=live}} (Search for 'church')</ref> Each talk is first given at various Perl conferences and is eventually also published online.

{{anchor|JAPH}} In email, Usenet, and message board postings, "Just another Perl hacker" (JAPH) programs are a common trend, originated by Randal L. Schwartz, one of the earliest professional Perl trainers.<ref>{{cite newsgroup |last1=Schwartz |first1=Randal L. |author1-link=Randal L. Schwartz |title=Who is Just another Perl hacker? |message-id=m1hfpvh2jq.fsf@halfdome.holdit.com |newsgroup=comp.lang.perl.misc |date=1999-05-02 |url=https://groups.google.com/forum/#!msg/comp.lang.perl.misc/nK-lswsaMec/DBL87v4FxOwJ |access-date=December 5, 2014 |archive-date=July 8, 2012 |archive-url=https://archive.today/20120708165748/http://groups.google.com/group/comp.sys.acorn.programmer/browse_thread/thread/b5fd3717bda6a8d0/d4d3e151a783dffa?lnk=gst&q=ioc%23d4d3e151a783dffa#!msg/comp.lang.perl.misc/nK-lswsaMec/DBL87v4FxOwJ |url-status=live}}</ref> In the parlance of Perl culture, Perl programmers are known as Perl hackers, and from this derives the practice of writing short programs to print out the phrase "Just another Perl hacker{{sic|,}}". In the spirit of the original concept, these programs are moderately obfuscated and short enough to fit into the signature of an email or Usenet message. The "canonical" JAPH as developed by Schwartz includes the comma at the end, although this is often omitted.<ref>{{cite web |url=http://www.perlmonks.org/bare/?node_id=443856 |title=Canonical JAPH |access-date=2011-05-16 |last=Schwartz |first=Randal |author-link=Randal L. Schwartz |date=2005-03-31 |publisher=PerlMonks |archive-date=July 22, 2011 |archive-url=https://web.archive.org/web/20110722055125/http://www.perlmonks.org/bare/?node_id=443856 |url-status=live}}</ref>

{{Anchor|Perl golf}} Perl "golf" is the pastime of reducing the number of characters (key "strokes") used in a Perl program to the bare minimum, much in the same way that golf players seek to take as few shots as possible in a round. The phrase's first use<ref name="perl-golf-coined">{{cite newsgroup |last1=Bacon |first1=Greg |title=Re: Incrementing a value in a slice |message-id=7imnti$mjh$1@info2.uah.edu |newsgroup=comp.lang.perl.misc |date=1999-05-28 |url=http://groups.google.com/group/comp.lang.perl.misc/msg/7b97c434492c8d20 |access-date=2011-07-12 |archive-date=July 7, 2011 |archive-url=https://web.archive.org/web/20110707134412/http://groups.google.com/group/comp.lang.perl.misc/msg/7b97c434492c8d20 |url-status=live}}</ref> emphasized the difference between pedestrian code meant to teach a newcomer and terse hacks likely to amuse experienced Perl programmers, an example of the latter being JAPHs that were already used in signatures in Usenet postings and elsewhere. Similar stunts had been an unnamed pastime in the language APL in previous decades. The use of Perl to write a program that performed RSA encryption prompted a widespread and practical interest in this pastime.<ref name="rsa">{{cite web |url=http://www.cypherspace.org/rsa/pureperl.html |title=RSA in 5 lines of perl |access-date=2011-01-10 |last=Back |first=Adam |archive-date=January 19, 2011 |archive-url=https://web.archive.org/web/20110119154503/http://www.cypherspace.org/rsa/pureperl.html |url-status=live}}</ref> In subsequent years, the term "code golf" has been applied to the pastime in other languages.<ref>{{cite web |url=http://codegolf.com/ |title=Code Golf: What is Code Golf? |publisher=29degrees |year=2007 |access-date=November 26, 2018 |archive-url=https://web.archive.org/web/20120113152453/http://codegolf.com/ |archive-date=January 13, 2012 |url-status=dead |df=mdy-all}}</ref> A Perl Golf Apocalypse was held at Perl Conference 4.0 in Monterey, California in July 2000.

As with C, obfuscated code competitions were a well known pastime in the late 1990s. The Obfuscated Perl Contest was a competition held by The Perl Journal from 1996 to 2000 that made an arch virtue of Perl's syntactic flexibility. Awards were given for categories such as "most powerful"—programs that made efficient use of space—and "best four-line signature" for programs that fit into four lines of 76 characters in the style of a Usenet signature block.<ref name="gallo03">{{cite book |last1=Gallo |first1=Felix |title=Games, diversions, and Perl culture: best of the Perl journal |chapter=The Zeroth Obfuscated Perl Contest |editor= Jon Orwant |publisher=O'Reilly Media |year=2003 |chapter-url=http://oreilly.com/catalog/tpj3/chapter/ch43.pdf |access-date=2011-01-12 |url-status=dead |archive-url=https://web.archive.org/web/20091122114544/http://oreilly.com/catalog/tpj3/chapter/ch43.pdf |archive-date=November 22, 2009 |df=mdy-all}}</ref>

Perl poetry is the practice of writing poems that can be compiled as legal Perl code, for example the piece known as "Black Perl". Perl poetry is made possible by the large number of English words that are used in the Perl language. New poems are regularly submitted to the community at PerlMonks.<ref>{{cite web |url=http://www.perlmonks.org/?node_id=1590 |title=Perl Poetry |access-date=2011-01-27 |publisher=PerlMonks |archive-date=September 27, 2007 |archive-url=https://web.archive.org/web/20070927000904/http://www.perlmonks.org/?node_id=1590 |url-status=live}}</ref>

=== Yet Another Perl Conference ===

'''Yet Another Perl Conference'''<ref name="Tom2012">{{cite book |last1=Christiansen |first1=Tom |last2=d foy |first2=brian |last3=Wall |first3=Larry |last4=Orwant |first4= Jon |title=Programming Perl: Unmatched power for text processing and scripting |date=2012 |publisher=O'Reilly Media, Inc. |isbn=978-1-4493-2146-8 |url=https://books.google.com/books?id=qhV2XYSgTaMC&dq=Programming+Perl+%22Yet+Another+Perl+Conference%22&pg=PA754 |accessdate=21 Dec 2025 |language=en}}</ref>{{rp|754}}<ref>{{cite book |last1=Arlow |first1=Jim |title=Enterprise Patterns and MDA: Building Better Software with Archetype Patterns and UML |date=2003 |publisher=Addison-Wesley Professional |isbn=978-0-1327-0253-9|url=https://books.google.com/books?id=_fSVKDn7v04C&dq=%22Yet+Another+Perl+Conference%22&pg=PA14 |accessdate=21 Dec 2025 |language=en}}</ref>{{rp|14}} (also called '''YAPC'''), from 2016–2019 called '''The Perl Conference''' ('''TPC'''), from 2020 on '''The Perl and Raku Conference''', is a series of conferences discussing the Perl programming language, that has run since 1999. It is usually organized under the auspices of The Perl Foundation and Yet Another Society, a "non-profit corporation for the advancement of collaborative efforts in computer and information sciences".

==== History ==== The first YAPC was held at Carnegie Mellon University in Pittsburgh, Pennsylvania, US on June 24 and June 25, 1999,<ref name="Tom2012" /> organized by Kevin Lenzo.<ref>{{Cite book |last1=Christiansen |first1=Tom |url=https://books.google.com/books?id=qhV2XYSgTaMC&dq=%22yet+another+perl+conference%22+yapc&pg=PA754 |title=Programming Perl: Unmatched power for text processing and scripting |last2=foy |first2=brian d |last3=Wall |first3=Larry |last4=Orwant |first4=Jon |date=2012-02-17 |publisher=O'Reilly Media, Inc. |isbn=978-1-4493-2146-8 |pages=754 |language=en}}</ref> YAPC's origins were in the not-for-profit Perl Mongers user group.<ref>{{Cite book |last=Pierce |first=Clinton |url=http://archive.org/details/perldevelopersdi0000pier |title=Perl developer's dictionary |date=2002 |publisher=Indianapolis, Ind. : Sams |others=Internet Archive |isbn=978-0-672-32067-5 |pages=13–14}}</ref><ref name=":1">{{Cite book |last=Scott |first=Peter |url=http://archive.org/details/perlmedic00pete |title=Perl Medic [electronic resource] : Transforming Legacy Code |date=2004 |publisher=Boston : Addison Wesley Professional |others=Internet Archive |isbn=978-0-201-79526-4 |pages=287–288}}</ref> The first conference assembled 31 different speakers into the schedule on various Perl-related topics.

The idea of a low-cost Perl conference quickly spread. The first European version of YAPC was organized by members of the Perl Mongers in London in 2000,<ref>{{Cite book |last1=Christiansen |first1=Tom |url=https://books.google.com/books?id=qhV2XYSgTaMC&dq=%22yet+another+perl+conference%22+yapc&pg=PA754 |title=Programming Perl: Unmatched power for text processing and scripting |last2=foy |first2=brian d |last3=Wall |first3=Larry |last4=Orwant |first4=Jon |date=2012-02-17 |publisher=O'Reilly Media, Inc. |isbn=978-1-4493-2146-8 |pages=754 |language=en}}</ref> Israel in 2003,<ref name=":1" /> Australia in 2004, Asia and Brazil in 2005, and Russia in 2008. The only continents never to have hosted a YAPC are Africa and Antarctica.

In 2016, YAPC rebranded itself as The Perl Conference,<ref>{{cite book |last1=Christiansen |first1=Tom |url=https://books.google.com/books?id=qhV2XYSgTaMC&dq=Programming+Perl+%22Yet+Another+Perl+Conference%22&pg=PA757 |title=Programming Perl: Unmatched power for text processing and scripting |date=2012 |publisher=O'Reilly Media, Inc. |isbn=978-1-4493-2146-8 |language=en |accessdate=21 Dec 2025}}</ref>{{rp|757}} which is the former name of O'Reilly Open Source Convention (OSCON). As of 2020, it is now calling itself The Perl and Raku Conference to reflect the renaming of Perl 6 to Raku.

==== Reception ==== By 2002, ''The Perl Developer's Dictionary'' listed YAPC as the second-most important conference in the Perl scene, after O'Reilly's Open Source Conference.<ref name=":0" /> ''Minimal Perl'' describes YAPC as "a collection of low-priced grassroots events held around the world for the benefit of those who either can’t afford the expense of the more elaborately staged conferences or just prefer the company of students and geeks to corporate IT types."<ref>{{Cite book |last=Maher |first=Tim |url=http://archive.org/details/minimalperlforun0000mahe |title=Minimal Perl : for UNIX and Linux people |date=2007 |publisher=Greenwich, Conn. : Manning |others=Internet Archive |isbn=978-1-932394-50-4 |pages=440}}</ref> The conference is recommended in various other books about Perl programming from the 2000s.<ref>{{Cite book |last=Mark LeBlanc |url=http://archive.org/details/perlforexploring00lebl |title=Perl for exploring DNA |date=2007 |publisher=Oxford University Press |others=Internet Archive |isbn=978-0-19-530589-0 |pages=292}}</ref>

The Dutch ''Linux Magazine'' reviewed the second European YAPC conference, held in Amsterdam in 2001, and describes the consternation when organisers revealed they had been listening in on network traffic and had found that several participants used unencrypted passwords, despite the conference theme being security.<ref name=":2" /> Other topics that year included building user interfaces, using Perl for speech, and parallel programming, and the conference had three parallel sessions with around 250 participants.

The name is an homage to yacc, "Yet Another Compiler Compiler".

==== Locations ====

===== North America ===== * 1999: Pittsburgh, Pennsylvania, USA (June 24–25, 1999) [http://www.yapc.org/America/previous-years/1999/ YAPC::NA 1999] * 2000: Pittsburgh, Pennsylvania, USA (June 21–23, 2000) [http://www.yapc.org/America/previous-years/19100/ YAPC::NA 19100] * 2001: Montréal, Québec, Canada (June 13 – June 15, 2001) [http://www.yapc.org/America/previous-years/2001/ YAPC::NA 2001] {{Webarchive|url=https://web.archive.org/web/20160309044220/http://www.yapc.org/America//previous-years/2001/ |date=2016-03-09 }} * 2002: Saint Louis, Missouri, USA (June 26 – June 28, 2002) [http://www.yapc.org/America/previous-years/2002/ YAPC::NA 2002] {{Webarchive|url=https://web.archive.org/web/20160303170020/http://www.yapc.org/America/previous-years/2002/ |date=2016-03-03 }} * 2003: Canada: Ottawa, Ontario, Canada (May 15–16, 2003) (held as YAPC::Canada) [https://web.archive.org/web/20030608051546/http://www.yapc.ca/ YAPC::Canada] * 2003: America: Boca Raton, Florida, USA (June 16–18, 2003) [http://www.yapc.org/America/previous-years/2003/ YAPC::NA 2003] {{Webarchive|url=https://web.archive.org/web/20160303180502/http://www.yapc.org/America/previous-years/2003/ |date=2016-03-03 }} * 2004: Buffalo, New York, USA (June 16–18, 2004) [http://www.yapc.org/America/previous-years/2004/ YAPC::NA 2004] {{Webarchive|url=https://web.archive.org/web/20150809222524/http://www.yapc.org/America/previous-years/2004/ |date=2015-08-09 }} * 2005: Toronto, Ontario, Canada (June 27–29, 2005) [http://www.yapc.org/America/previous-years/2005/ YAPC::NA 2005] {{Webarchive|url=https://web.archive.org/web/20150809211449/http://www.yapc.org/America/previous-years/2005/ |date=2015-08-09 }} * 2006: Chicago, Illinois, USA (June 26–30, 2006) 2006) [http://yapc.org/America/previous-years/2006/ YAPC::NA 2006] * 2007: Houston, Texas, USA (June 25–27, 2007) [http://conferences.mongueurs.net/yn2007/ YAPC::NA 2007] * 2008: Chicago, Illinois, USA (June 16–18, 2008) [http://conferences.mongueurs.net/yn2008/ YAPC::NA 2008] * 2009: Pittsburgh, Pennsylvania, USA (June 22–24, 2009) [http://www.yapcna.org/yn2009/ YAPC::NA 2009] * 2010: Columbus, Ohio, USA (June 21–23, 2010) [http://www.yapcna.org/yn2010/ YAPC::NA 2010] * 2011: Asheville, North Carolina, USA (June 27–30, 2011) [http://www.yapcna.org/yn2011/ YAPC::NA 2011] * 2012: Madison, Wisconsin, USA (June 13–15, 2012) [http://2012.yapcna.org/ YAPC::NA 2012] {{Webarchive|url=https://web.archive.org/web/20150905090349/http://2012.yapcna.org/ |date=September 5, 2015 }} * 2013: Austin, Texas, USA (June 3–5, 2013) [http://www.yapcna.org/yn2013/ YAPC::NA 2013] * 2014: Orlando, Florida, USA (June 23–25, 2014) [http://www.yapcna.org/yn2014/ YAPC::NA 2014] * 2015: Salt Lake City, Utah, USA (June 8–10, 2015) [http://www.yapcna.org/yn2015/ YAPC::NA 2015] * 2016: Orlando, Florida, USA (June 20–22, 2016) [http://www.yapcna.org/yn2016/ YAPC::NA 2016] * 2017: Alexandria, Virginia, USA (June 18–23, 2017) [https://perlconference.us/tpc-2017-dc/ The Perl Conference in DC] * 2018: Salt Lake City, Utah, USA (June 17–22, 2018) [https://perlconference.us/tpc-2018-slc/ The Perl Conference in Salt Lake City] * 2019: Pittsburgh, Pennsylvania, USA (June 16–21, 2019) [https://perlconference.us/tpc-2019-pit/ The Perl Conference in Pittsburgh] * 2020: Online (due to COVID-19) (Wednesday 24th to Friday 26th 2020) [https://perlconference.us/tpc-2020-cloud/ Perl and Raku 'Conference in the Cloud'] ** Replaces [https://perlconference.us/tpc-2020-hou/ TPCiH 2020 Houston] {{Webarchive|url=https://web.archive.org/web/20200129153542/https://perlconference.us/tpc-2020-hou/ |date=2020-01-29 }} Tuesday, planned June 23rd through Saturday, June 27th * 2021 Conference in the Cloud (June 8–10, 2021) [https://perlconference.us/tprc-2021-cloud/ The Perl and Raku Conference in the Cloud] * 2022: Houston, TX (June 22–24, 2022) [https://perlconference.us/tprc-2022-hou/ TPCiH 2022 Houston] * 2023: Toronto, CA (July 11–13, 2023) [https://tprc.to/tprc-2023-tor/ The Perl and Raku Conference in Toronto] * 2024: Las Vegas, NV (June 24–28, 2024) [https://tprc.us/tprc-2024-las/ TPRC Las Vegas, NV] {{Webarchive|url=https://web.archive.org/web/20251214223313/https://tprc.us/tprc-2024-las/ |date=December 14, 2025 }} * 2025: Greenville, SC (June 27–29, 2025) [https://tprc.us/tprc-2025-gsp/ TPRC Greenville, SC]

===== Europe ===== * 2000: London, England (September 22–24, 2000) [http://www.yapceurope.org/2000/ YAPC::EU 2000] * 2001: Amsterdam, Netherlands (August 2–4, 2001) [http://www.yapceurope.org/2001/ YAPC::EU 2001]<ref name=":2">{{Cite journal |last=Hemel |first=Armijn |date=September 2001 |title=Linux samenscholing: YAPC::Europe 2.0.01 |url=https://archive.org/details/eu_Linux_Magazine_2001-10-NL_OCR/page/n55/mode/2up?q=%22yet+another+perl+conference%22 |journal=Linux Magazine |volume=2 |issue=5 |pages=56}}</ref> * 2002: Munich, Germany (September 18–20, 2002) [http://www.yapceurope.org/2002/ YAPC::EU 2002] * 2003: Paris, France (July 23–25, 2003) [http://conferences.mongueurs.net/ye2003/ YAPC::EU 2003] * 2004: Belfast, Northern Ireland (September 15–17, 2004) [https://web.archive.org/web/20090827101116/http://belfast.yapc.org/ YAPC::EU 2004] * 2005: Braga, Portugal (August 31 – September 2, 2005) [http://conferences.yapceurope.org/ye2005/ YAPC::EU 2005 ''Perl Everywhere''] * 2006: Birmingham, England (August 30 – September 1, 2006) [http://www.yapceurope.org/2006/ YAPC::EU 2006] * 2007: Vienna, Austria (August 28–30, 2007) [http://vienna.yapceurope.org/ye2007/ YAPC::EU 2007 ''Social Perl''] * 2008: Copenhagen, Denmark (August 13–15, 2008) [http://conferences.yapceurope.org/ye2008/ YAPC::EU 2008 ''Beautiful Perl''] * 2009: Lisbon, Portugal (August 3–5, 2009) [http://conferences.yapceurope.org/ye2009/ YAPC::EU 2009 ''Corporate Perl''] * 2010: Pisa, Italy (August 4–6, 2010) [http://conferences.yapceurope.org/ye2010/ YAPC::EU 2010 ''The Renaissance of Perl''] * 2011: Riga, Latvia (August 15–17, 2011) [http://yapceurope.lv/ye2011/ YAPC::EU 2011 ''Modern Perl''] {{Webarchive|url=https://web.archive.org/web/20110731115934/http://yapceurope.lv/ye2011/ |date=2011-07-31 }} * 2012: Frankfurt, Germany (August 20–22, 2012) [http://act.yapc.eu/ye2012/ YAPC::EU 2012]<ref>{{Cite web |title=Proceedings / YAPC::Europe 2012 : [Fourteenth European Perl Conference ; Frankfurt, August 20-22, 2012] {{!}} WorldCat.org |url=https://search.worldcat.org/title/931405345 |access-date=2025-12-23 |website=search.worldcat.org |language=en}}</ref> * 2013: Kyiv, Ukraine (August 12–14, 2013) [http://act.yapc.eu/ye2013/ YAPC::EU 2013 ''Future Perl''] * 2014: Sofia, Bulgaria (August 22–24, 2014) [http://act.yapc.eu/ye2014/ YAPC::EU 2014] * 2015: Granada, Spain (September 2–4, 2015) [http://act.yapc.eu/ye2015/ YAPC::EU 2015 ''Art+Engineering''] * 2016: Cluj-Napoca, Romania (August 24–26, 2016) [http://act.yapc.eu/ye2016 YAPC::Europe 2016] * 2017: Amsterdam, the Netherlands (August 9–11, 2017) [http://act.perlconference.org/tpc-2017-amsterdam/ The Perl Conference in Amsterdam] * 2018: Glasgow (August 13–17, 2018) [http://act.perlconference.org/tpc-2018-glasgow/ The Perl Conference in Glasgow] * 2019: Riga (August 7–9, 2019) [https://perlcon.eu/ PerlCon] * 2020: Amsterdam (August 10–14, 2020) [https://perlrakucon.eu/ Perl & Raku Con in Amsterdam] {{Webarchive|url=https://web.archive.org/web/20251205205655/https://perlrakucon.eu/ |date=December 5, 2025 }} – cancelled due to the Coronavirus pandemic * 2023: Helsinki (August 14–18, 2023) [https://perlkohacon.fi/ Perl & Koha Conference in Helsinki]

===== Israel ===== * 2003: Haifa (May 11, 2003) [https://web.archive.org/web/20131020190628/http://perl.org.il/YAPC/2003/ YAPC::Israel::2003] * 2004: Herzliya (February 26, 2004) [https://web.archive.org/web/20131009202100/http://perl.org.il/YAPC/2004/ YAPC::Israel::2004] * 2005: Herzliya (February 17, 2005) [https://web.archive.org/web/20131009192401/http://perl.org.il/YAPC/2005/ YAPC::Israel::2005] * 2006: Netanya. In 2006, YAPC::Israel became OSDC::Israel. [https://web.archive.org/web/20060101073845/http://www.osdc.org.il/ OSDC::Israel 2006]

===== Russia & Ukraine ===== * 2008: Moscow, Russia (May 17–18, 2008) [http://event.perlrussia.ru/yr2008/ YAPC::Russia 2008 ''May Perl''] {{Webarchive|url=https://web.archive.org/web/20150925035442/http://event.perlrussia.ru/yr2008/ |date=2015-09-25 }} * 2009: Moscow, Russia (May 16–17, 2009) [http://event.yapcrussia.org/mayperl2/ YAPC::Russia 2009 ''May Perl 2''] * 2010: Kyiv, Ukraine (June 12–14, 2010) [http://social.yapcrussia.org/yr2010/ YAPC::Russia 2010 ''May Perl + Perl Mova''] {{Webarchive|url=https://web.archive.org/web/20101022162505/http://social.yapcrussia.org/yr2010/ |date=2010-10-22 }} * 2011: Moscow, Russia (May 14–15, 2011) [http://event.yapcrussia.org/mayperl4/ YAPC::Russia 2011 ''May Perl + Perl Mova''] * 2012: Kyiv, Ukraine (May 12–13, 2012) [http://event.yapcrussia.org/yr2012/ YAPC::Russia ''May Perl''] * no event held in 2013, due to YAPC::Europe 2013 taking place in Kyiv * 2014: St. Petersburg, Russia (June 13–14, 2014) [http://event.yapcrussia.org/yr2014/ YAPC::Russia 2014] * 2015: Moscow, Russia (May 16–17, 2015) [http://event.yapcrussia.org/yr2015/ YAPC::Russia 2015] * 2017: Moscow, Russia (November 4, 2016) YAPC::Russia 2017

===== Australia ===== * The first YAPC::Australia was held as part of the 2004 OSDC in Melbourne from December 1-December 5, 2004, and has been held jointly thereafter.

===== South America ===== These events are held in conjunction with CONISLI. * 2006: Porto Alegre/RS (April 19–22, 2006) [https://web.archive.org/web/20070319183618/http://www.perl.org.br/bin/view/YAPC/SA2006 YAPC::SA::2006] * 2007: Porto Alegre/RS (April 11–14, 2007) [https://web.archive.org/web/20120305025406/http://www.perl.org.br/YAPC/SA2007/WebHome YAPC::SA::2007] * 2008: Porto Alegre/RS (April 17–19, 2008) [https://web.archive.org/web/20101128110124/http://www.perl.org.br/YAPC/SA2008/WebHomeEn YAPC::SA::2008] * 2009: Porto Alegre/RS (June 24–27, 2009) [https://web.archive.org/web/20120222215214/http://www.perl.org.br/YAPC/SA2009/ YAPC::SA::2009]

====== Brazil ====== * 2005: Porto Alegre/RS (June 1–5, 2005) YAPC::Brasil 2005 * 2006: São Paulo/SP, Brazil (November 3–5, 2006) [http://perl.org.br/bin/view/YAPC/YAPCBrasil2006 YAPC::Brasil 2006] {{Webarchive|url=https://web.archive.org/web/20061116055704/http://www.perl.org.br/bin/view/YAPC/YAPCBrasil2006 |date=2006-11-16 }} * 2007: São Paulo/SP, Brazil (November 9–11, 2007) [https://web.archive.org/web/20101212194125/http://www.perl.org.br/YAPC/BR2007/ YAPC::Brasil 2007] * 2008: São Paulo/SP, Brazil (October 18–19, 2008) [https://web.archive.org/web/20101227101818/http://www.perl.org.br/YAPC/BR2008/ YAPC::Brasil 2008] * 2009: Niterói/RJ, Brazil (October 30 – November 1, 2009) [https://web.archive.org/web/20091021142551/http://www.yapcbrasil.org.br/2009/ YAPC::Brasil 2009] * 2010: Fortaleza/CE, Brazil (October 25–31, 2010) [https://web.archive.org/web/20140719011809/http://www.yapcbrasil.org.br/2010 YAPC::Brasil 2010 ''Perl: Solução e Integração de Negócios''] * 2011: Rio de Janeiro/RJ, Brazil (November 4–6, 2011) [https://web.archive.org/web/20150218004509/http://www.yapcbrasil.org.br/2011/ YAPC::Brasil 2011] * 2012: São Paulo/SP, Brazil (October 19–20, 2012) [https://web.archive.org/web/20150219041502/http://yapcbrasil.org.br/2012/ YAPC::Brasil 2012 ''A revolução dos dados''] * 2013: Curitiba/PR, Brazil (November 15–16, 2013) [https://web.archive.org/web/20130929000455/http://2013.yapcbrasil.org.br/ YAPC::Brasil 2013 ''Universo Científico e Perl Hacking''] * 2014: Itapema/SC, Brazil (September 19–20, 2014) [https://web.archive.org/web/20140809024243/http://2014.yapcbrasil.org.br/ YAPC::Brasil 2014 ''Soluções Tecnológicas para Gestão Pública''] * 2015: Taubaté/SP, Brazil (September 18–20, 2015) [http://yapcbrasil2015.org/ YAPC::Brasil 2015 ''Perl Community and CPAN'']{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}

===== Asia ===== * 2004: Taipei, Taiwan (March 27–28, 2004) [http://www.openfoundry.org/tw/foss-news/604-yapc2004taipei-327-28 YAPC::2004::Taipei] {{Webarchive|url=https://web.archive.org/web/20150924060918/http://www.openfoundry.org/tw/foss-news/604-yapc2004taipei-327-28 |date=2015-09-24 }} * 2005: Taipei, Taiwan (March 26–27, 2005) (held as YAPC::Taipei) [http://www.openfoundry.org/news/175 YAPC::2005::Taipei] {{Webarchive|url=https://web.archive.org/web/20150924060900/http://www.openfoundry.org/news/175 |date=2015-09-24 }} * 2006: Tokyo, Japan (March 29–30, 2006) [http://tokyo.yapcasia.org/blog/ YAPC::Asia 2006] * 2007: Tokyo, Japan (April 4–5, 2007) [http://tokyo2007.yapcasia.org/blog/ YAPC::Asia 2007] * 2008: Tokyo, Japan (May 15–16, 2008) [http://conferences.yapcasia.org/ya2008/ YAPC::Asia 2008] * 2009: Tokyo, Japan (September 10–11, 2009) [http://conferences.yapcasia.org/ya2009/ YAPC::Asia 2009] * 2010: Tokyo, Japan (October 15–16, 2010) [http://yapcasia.org/2010/ YAPC::Asia 2010] * 2011: Tokyo, Japan (October 14–15, 2011) [http://yapcasia.org/2011/ YAPC::Asia 2011] * 2012: Tokyo, Japan (September 27–29, 2012) [http://yapcasia.org/2012/ YAPC::Asia 2012] * 2013: Tokyo, Japan (September 19–21, 2013) [http://yapcasia.org/2013/ YAPC::Asia 2013] * 2014: Tokyo, Japan (August 28–30, 2014) [http://yapcasia.org/2014/ YAPC::Asia 2014] * 2015: Tokyo, Japan (August 20–22, 2015) [http://yapcasia.org/2015/ YAPC::Asia 2015] * 2016: Hokkaido, Japan (9–10 December 2016) [https://yapcjapan.org/2016hokkaido/ YAPC::Hokkaido] * 2017: Kansai (3–4 March 2017) [https://yapcjapan.org/2017kansai/ YAPC::Kansai 2017] * 2017: Fukuoka (30th June – 1st July) [https://yapcjapan.org/2017fukuoka/ YAPC::Fukuoka 2017] * 2018: Okinawa (2–3 March 2018)[https://yapcjapan.org/2018okinawa/ YAPC::Okinawa 2018] * 2019: Tokyo, Japan (25–26 January 2019) [https://yapcjapan.org/2019tokyo/ YAPC::Tokyo 2019] * 2020: Kyoto, Japan (March 27–28, 2020) [https://yapcjapan.org/2020kyoto/ YAPC::Kyoto 2020] * 2021: Online, YAPC::Japan (February 18–19, 2021) [https://yapcjapan.connpass.com/event/198170/ YAPC::Japan 2021] * 2022: Online, YAPC::Japan (March 4–5, 2022) [https://yapcjapan.org/2022online/ YAPC::Japan 2022] * 2022: Kyoto, Japan (March 19, 2023) [https://yapcjapan.org/2023kyoto/ YAPC::Kyoto 2023] * 2024: Hiroshima, Japan (February 10, 2024) [https://yapcjapan.org/2024hiroshima/ YAPC::Hiroshima 2024] * 2024: Hakodate, Japan (October 5, 2024) [https://yapcjapan.org/2024hakodate/ YAPC::Hakodate 2024] * 2025: Fukuoka, Japan (November 14–15, 2025) [https://yapcjapan.org/2025fukuoka/ YAPC::Fukuoka 2025]

==See also== {{Portal|Free and open-source software|Computer programming}} * List of Perl programming books * List of Perl software and tools * Outline of Perl * Perl Data Language * Perl Object Environment * Plain Old Documentation

==References== {{Reflist}}

==Further reading== * [http://shop.oreilly.com/product/0636920018452.do Learning Perl] 6th Edition (2011), O'Reilly. Beginner-level introduction to Perl. * [http://ofps.oreilly.com/titles/9781118013847/index.html Beginning Perl] 1st Edition (2012), Wrox. A beginner's tutorial for those new to programming or just new to Perl. * [http://onyxneon.com/books/modern_perl/ Modern Perl] {{Webarchive|url=https://web.archive.org/web/20111222045417/http://onyxneon.com/books/modern_perl/ |date=December 22, 2011}} 2nd Edition (2012), Onyx Neon. Describes Modern Perl programming techniques. * [http://shop.oreilly.com/product/9780596004927.do Programming Perl] 4th Edition (2012), O'Reilly. The definitive Perl reference. * [http://www.pearsonhighered.com/educator/product/Effective-Perl-Programming-Ways-to-Write-Better-More-Idiomatic-Perl-2E/9780321496942.page Effective Perl Programming] 2nd Edition (2010), Addison-Wesley. Intermediate- to advanced-level guide to writing idiomatic Perl. * ''Perl Cookbook'', {{ISBN|0-596-00313-7}}. Practical Perl programming examples. * {{cite book |last=Dominus |first=Mark Jason |title=Higher Order Perl |url=http://hop.perl.plover.com/book/ |year=2005 |publisher=Morgan Kaufmann |isbn=978-1-55860-701-9}} Functional programming techniques in Perl.

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