I use /proc/*/cwd WAY too often at work...because nobody documents FUCKING ANYTHING around here, so when shit doesn't work you find the responsible process on another environment and use the cwd to figure out where the hell the code is located...or at least that's how I do it, rather than just asking dozens of people until you get lucky and one of them remembers...IHTFP...
In theory, the thing I'm working on does have rather extensive documentation, with a ton of flowcharts, including pages and pages flagged as "OBSOLETE"... but of course the part that's broken isn't fuckin in there...