Unix commands definitely go a long ways. I've been freelancing for a long time but never automated invoicing people up until recently. So I combined grep, cut

Unix commands definitely go a long ways. I've been freelancing for a long time but never automated invoicing people up until recently. So I combined grep, cut, paste and bc to parse a work log file to get how many hours I worked on that project, what amount I am owed and how many days I worked. I can run these analytics by just passing in the log file, a YYYY/MM date (this month's numbers), YYYY date (yearly numbers) or no date (lifetime). Long story short, the working prototype of it was 4 lines of Bash and took about 10 minutes to make. Now I never have to manually go through these work log files again and add up invoice amounts (which I always counted up manually 3 times in a row to avoid mistakes). If you're sending a bunch of invoices a month, this actually took kind of a long time and was always error prone.