Running Linux, Third Edition

Using Perl

Perl may well be the best thing to happen to the Unix programming environment in years; it is worth the price of admission to Linux alone. Perl is a text- and file-manipulation language, originally intended to scan large amounts of text, process it, and produce nicely formatted reports from that data. However, as Perl has matured, it has developed into an all-purpose scripting language, capable of doing everything from managing processes to communicating via TCP/IP over a network. Perl is free software developed by Larry Wall, the Unix guru who brought us the rn newsreader and various popular tools, such as patch.

Perl’s main strength is that it incorporates the most widely used features of languages, such as C, sed, awk, and various shells, into a single interpreted script language. In the past, getting a complicated job done was a matter of juggling these various languages into complex arrangements, often entailing sed scripts piping into awk scripts piping into shell scripts and eventually piping into a C program. Perl gets rid of the common Unix philosophy of using many small tools to handle small parts of one large problem. Instead, Perl does it all, and it provides many different ways of doing the same thing. In fact, this chapter was written by an Artificial Intelligence program developed in Perl. (Just kidding, Larry.)

Perl provides a nice programming interface to many features that were sometimes difficult to use in other languages. For example, a common task ...