Perl

Abstract

We have to deal with perl! Why? Because it is a great and, especially among scientists, widely applied programming language — but not least also for historical reasons: perl was initially developed to integrate features of sed and awk within the framework provided by the shell. As you learned before, awk is a programming language with powerful string manipulation commands and regular expressions that facilitates file formatting and analysis. The stream editor sed nicely complements awk. In 1986, the system programmer Larry Wall worked for the US National Security Agency. He was responsible for building a control and management system with the capability to produce reports for a wide-area network of Unix computers. Unhappy with the available tools, he invented a new language: perl. Beside integrating sed and awk he was inspired by his background in linguistics to make perl a “human”-like language, which enables the expression of ideas in different ways. This feature makes perl scripts sometimes hard to read because there are too many ways to do one thing. The first version of the Practical Extraction and Report Language, perl, was released as open source in 1987. Since then perl has been growing and growing and growing - now even providing tools for biologists in the form of special commands via bioperl (see Sect. 12.13 on page 254).