In grad school, I once saw a prof I was working with grab a text file and in seconds manipulate it into little pieces so deftly it blew my mind. I immediately decided it was time for me to learn awk, which he had so clearly mastered.
via gregable.com
Awk is my main tool for doing any type of POC where grinding through text is the order of the day. I've used it transform and analyze large legacy code bases of C, SQL, Java and especially COBOL. Processing logs is also easy work... AWK is well worth your investment in time if you work regularly with processing and analyzing text.