After two previous posts about punchcard graph, now this is the third one. Three is the charm, right?
I was thinking about punchcard in ASCII, but someone has written one, punchcard.awk. I made some modifications in my fork, simplifying some code, fixing a tiny issue, and adding support of Unix times.
It was written for Git log, now you can just pipe in ~/.bash_history or any file is a list of Unix timestamps. Here is a screenshot:
