Perl is a high-level programming language based loosely on C. Its file and text manipulation facilities make it particularly well-suited for tasks related to managing ArcInfo inputs and outputs. If you are familiar with basic programming concepts, Perl is easy to learn, and, in my opinion, well worth while.
The easiest way to see if Perl is already installed on your system is to type perl at the system prompt. If it looks like the machine is waiting for input, then you have Perl. If you get an error, you don't.
If you don't have Perl, don't worry. It is easy to download and install on both the UNIX and Windows platforms. And the price is right -- it's free.
Perl for Windows can be downloaded from http://www.activestate.com/Products/ActivePerl. The latest release features standard Windows install/uninstall routines and comprehensive HTML documentation.
Binaries for the standard release of Perl for UNIX is now available for most platforms. You can find the relevant links at http://www.perl.com/CPAN/, which also has a variety of resources to get you started with Perl. Perl for UNIX is distributed as source code, and builds with no porting whatsoever on most Unix systems. Don't worry: It has one of the easiest install scripts I have ever used.
If you would like more information about Perl, try the Perl Frequently Asked Questions (FAQ) document.
There are a few good books available to learn about programming Perl; I recommend the following two:
Entire site © 1996-2004 by Christopher Eykamp