Perl

A script programming language used to process text. It runs on many platforms (including Windows and Macintosh) and is installed on most Unix workstations. It is available for free and allows Web developers to quickly write code or perform system administration tasks.

Historical perspective: Created by linguist Larry Wall in 1987 to mimic natural languages, it is considered "the duct tape of the Internet" and has been hailed as the single most important tool for expanding Web sites quickly. More than half of the sites on the Web are built using Perl as the foundation that holds together text files and other applications. Perl is also viewed by many as "the poster child of the open source software revolution" because volunteer programmers from all over the world work together to make it better.