Curate Your Shell History

Summary

Simon Tatham wrote an article recently called “Policy of transience”, explaining (among other things) why you might want to disable your shell history file. Simon writes: My unusual habit is: turn off the history file completely, by putting the command ‘unset HISTFILE’ in my .bashrc. I still get history within a single instance of the shell, so I can edit my last command ten times until it works properly; but history isn’t shared between my terminal windows, or preserved when I log out and log in again. All the shell history I allow myself is localised and short-term. […] If I type a shell command that’s valuable – one that did something useful enough that I might want it again in future, and long and complicated enough that I’d be annoyed to have to figure it out a second time from scratch – then I can’t rely on it just happening to be in my .bash_history. So instead I put it somewhere else: maybe a shell function in my .bashrc, or maybe a shell script in my directory of random useful scriptlets. Or maybe just in a file of notes jotted down to myself about useful shell runes to remember. I find this a more useful way to remember shell commands. Firstly, this procedure separates the working version of the command from all the failed attempts just before it. Even within the context of one instance of bash I’ll sometimes accidentally recall a wrong version of a command when I was aiming for the corrected one two commands later; the idea of having a year’s worth of my own false starts available for accidental recall seems horrifying! Instead, I deliberately save just the working version, and let all the failed attempts go in the trash when I close the shell. For me, this idea feels uncomfortable! If anything, I’m a shell history maximalist; I have zsh configured to save my last 9,800 commands. I rely heavily on my shell history to remember how I did things before. I suspect my most-used form of zsh completion is to complete the current command line from a history entry...