What kind of analytic software?
There are tons of web analysis programs.
If you are looking for something beyond that, many use grep/sed/awk in *nix. Knowledge of relative expression is required for your search queries.
Relative expression is definitely a good starting point for any sort of text analysis.
Maybe there are some specific software out there based on what you are wanting to do though.
Here is a PDF for an introduction to text based analysis, probably more info than you wanted, but still interesting!
http://www.cis.gsu.edu/~dtruex/Presentations/tbintppr.pdf