ICE

ICE Index Perl script
Perl script to generate ICE form

A popular indexing and searching solution on the Web is ICE, written in PERL by Christian Neuss in Germany. It's freely available on the Internet at http://www.igd.fhg.de/~neuss/me.html and is included on the WebmasterCD. By default, ICE includes the following features:

Whole-word searching using Boolean operators (AND and OR)
Case-sensitive or case-insensitive searching
Hypertext presentation of scored results
The ability to look for similarly-spelled words in a dictionary
The ability to find related words and topics in a thesaurus
The ability to limit searches to a specified directory tree

Note: Because it's written in PERL, ICE can run on any platform for which PERL is available, including UNIX, Windows NT, Mac, DOS, and OS/2. However, some modifications are necessary because of the differences in file systems employed by these operating systems.