As moritz pointed out, you must know what concepts data represent to decide on what is important, e.g. a series of 0-s might be useless as suggested by you, when in sound silence-finding application it is crucial.

My advice is to try a little bit looking what might be promissing for you. Experiment with regular expressions filtering and see it obtained results are interesting. If so, go on and filter/ group/ sort more, ad infinitum. Something like

perl -ne 'print if /^INSAUTH\b/'
[download]

would produce the output you mention.

Further, Text::CSV is a possible improvement on data analysis preparations.