Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. 'Perl' usually refers to Perl 5, but it may also refer to its redesigned 'sister language', Perl 6. Though Perl is not officially an acronym, there are various backronyms in use, including 'Practical Extraction and Reporting Language'. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Perl 6, which began as a redesign of Perl 5 in 2000, eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from one another. The Perl languages borrow features from other programming languages including C, shell script (sh), AWK, and sed; Wall also alludes to BASIC and Lisp in the introduction to Learning Perl (Schwartz & Christiansen) and so on. They provide text processing facilities without the arbitrary data-length limits of many contemporary Unix commandline tools, facilitating manipulation of text files. Perl 5 gained widespread popularity in the late 1990s as a CGI scripting language, in part due to its unsurpassed regular expression and string parsing abilities. In addition to CGI, Perl 5 is used for system administration, network programming, finance, bioinformatics, and other applications, such as for GUIs. It has been nicknamed 'the Swiss Army chainsaw of scripting languages' because of its flexibility and power, and also its ugliness. 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. Larry Wall began work on Perl in 1987, while working as a programmer at Unisys, and released version 1.0 to the comp.sources.misc newsgroup on December 18, 1987. The language expanded rapidly over the next few years. Perl 2, released in 1988, featured a better regular expression engine. Perl 3, released in 1989, added support for binary data streams. 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. 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. 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.