In the SSL/CW list of top IT skills, Perl is number 34.
What is it?
Perl is a high-level language derived from a wide range of sources, including C and the Unix shell.
Perl is often called a scripting language, which has come to mean a tool for doing lightweight jobs on the web quickly, but without much skill or finesse. Perl is used in some mission-critical applications and is shipped by some serious players. It can be downloaded for free from www.perl.com.
Where did it originate?
Perl was created in 1987 by Larry Wall but, like Linux, it has been developed by a global community who describe themselves as, "a rag-tag band of highly altruistic individuals committed to producing better software for free than you could hope to buy".
Perl is rooted in the pre-commercial internet - Perl's distribution terms are even less restrictive than the GNU General Public Licence.
Perl5 replaced Perl4 in 1994 and the current version is 5.8. Although Perl5 was a ground-up rewrite, the emphasis is on backward-compatibility and most Perl4 scripts will still run.
What is it for?
"Perl tries to be all things to all people, but nothing special to anyone," according to the Perl website. It is used for everything from one-line file-processing tasks to large systems, where it offers a high-level substitute for C, C++ and Java. Applications include quick prototyping, system utilities, software tools, system management tasks, database access, graphical programming, networking and web programming.
What makes it special?
Perl is quick to learn, easy to use, well supported and extremely stable. You will not have your arm twisted to upgrade to a new version. If you do upgrade, you will not have to rewrite large chunks of your existing applications. It is also fully portable, so once written, Perl code should run anywhere.
How difficult is it to master?
It is easy to begin working with Perl if you have got C and Unix experience, although almost any programming background will do. The Perl website describes the Perl learning curve as shallow but long, meaning you do not need to know much to work with Perl but there is a lot to learn if you want to do it seriously.
What systems does it run on?
Various flavours of Unix, Linux, Windows, Macintosh and others. Commercial support is available for those who refuse to trust their mission-critical systems to a global network of sandal-wearing anarchists.
Where is it used?
There are well over one million Perl users worldwide and it is used in all kinds of companies, including Amazon.com, Barclays Bank and the Scottish Land Registry.
Open source software use is notoriously difficult to track and there is probably more Perl code around than installation managers know about.
Not many people know that...
Perl stands for Practical Extraction and Report Language. The "a" was probably dropped to avoid confusion with earlier languages also called Pearl.
What is coming up?
Perl6. Follow its development in weekly installments at www.perl.com.
There are lots of free tutorials on the web. Paid-for courses are available from independent companies such as Sun. O'Reilly publishes the definitive texts by Wall et al.