I've used it when I was doing a pentest - searching a network for leaks of information. I wrote dozens of shell scripts that scanned the network for .html files

I've used it when I was doing a pentest - searching a network for leaks of information. I wrote dozens of shell scripts that scanned the network for .html files, then extracted URL's from them, downloaded all of the files referenced in them, and searched those files (.doc, *.pdf, etc.) for metadata that contained sensitive information. This involved eliminating redundant URL's and files, using scripts to extract information which was piped into other scripts, and a dozen different ways of extracting metadata from from various file types. I wrote a lot of scripts that where long, single-use and complicated, and I used a Makefile to document and save these so I could re-do them if there was an update, or make variations of them if I had a new ideas.