# Which command did you run 1731 days ago? *Let's talk about shell history.* By Thorsten Ball • January 21, 2024 --- > *Professor Henry Jones*: Well, he who finds the Grail must face the final challenge. > > *Indiana Jones*: What final challenge? > > *Professor Henry Jones*: Three devices of such lethal cunning. > > *Indiana Jones*: Booby traps? > > *Professor Henry Jones*: Oh, yes. But I found the clues that will safely take us through them in the Chronicles of St. Anselm. > > *Indiana Jones*: [pleased] Well, what are they? > > [short pause as Henry tries to recall] > > *Indiana Jones*: Can’t you remember? > > *Professor Henry Jones*: I wrote them down in my diary so that I wouldn’t *have* to remember.                 ******* Recipe for living a good life in the shell: 1. Make sure it’s fast. 1. Make sure its history can grow nearly infinitely and you can fuzzy-search through it. The first one–fast shells–[we talked about last week](https://registerspill.thorstenball.com/p/how-fast-is-your-shell), so this time, let’s talk about shell history. On one of my machines the `~/.zsh_history` file contains 26278 commands. Its oldest entry was recorded on April 25, 2019. When I hit `Ctrl-r` in ZSH [fzf](https://github.com/junegunn/fzf) pops up and lets me fuzzy-search through all 26278 commands, through the last 5 years of my shell history. It’s glorious. [![](https://archive.thorstenball.com/data/images/140884708.which-command-did-you-run-1731-days/01532c09-5727-4ac5-8536-e20522bb90d4_800x518.gif)](https://archive.thorstenball.com/data/images/140884708.which-command-did-you-run-1731-days/01532c09-5727-4ac5-8536-e20522bb90d4_800x518.gif) That one `curl` command with these four strange HTTP headers that I had to send to make sure I could talk to my local dev env correctly through the reverse-proxy – that’s in there, a few keystrokes and some hazy memories away. That one `rsync` that uses the correct SSH client binary on the other side and that preserves timestamps and permission – also in there. The ugly bastard of a command that combined `git grep` with `find` and 8 ugly incantations of AWK chained together – locked in there too. The test command I ran yesterday is as reachable as the one command with 12 `&&` in it that I ran 3 years ago, all thanks to a long shell history file. Truly: `~/.zsh_history` is one of the most important files on my machine. I make use of it tens of times every day, whenever I hit `Ctrl-r`. If I wasn’t such a doofus it would contain even more than 26278 commands, because I’ve been keeping a long shell history for nearly a decade. But since I *am* such a doofus, I forgot to back it up (or deleted the backup too early) a few times and hence the `~/.zsh_history` on the machine I’m typing this only contains 1034 commands. Someone might say: “well, if the command was that important, why don’t you save it to a script?” And to that I say: look, man, if I knew in advance which command would turn out to be important, then we wouldn’t be here, because I’d already have ascended to the astral realm. Also: why *would* I record it in a script if I can just configure my shell to keep track of all of those commands for me? It’s cheap, it’s fast, there’s essentially no downsides to it: the largest `~/.zsh_history` I have is 2MB and I can fuzzy-search through it in *milliseconds*.                 ******* So, to repeat: your shell – ZSH, Bash, Fish, or others – can record every command you execute in it and I’m begging you to make sure it is configured to do that. Make sure it keeps track of *a lot* of commands. So many commands that when you put the number in your rc-file you think: that’s ridiculous, why would I need to record that many commands? Double that number. As the next and final step you need to get a fuzzy-finder fuzzy-finder to search through it. Here’s [the ZSH configuration](https://github.com/mrnugget/dotfiles/blob/2bdf21b659cbf34f21a0716bfac1f90914426a87/zshrc#L18-L35) I used for many, many years: ``` ########## # HISTORY ########## HISTFILE=$HOME/.zsh_history HISTSIZE=50000 SAVEHIST=50000 # Immediately append to history file: setopt INC_APPEND_HISTORY # Record timestamp in history: setopt EXTENDED_HISTORY # Expire duplicate entries first when trimming history: setopt HIST_EXPIRE_DUPS_FIRST # Dont record an entry that was just recorded again: setopt HIST_IGNORE_DUPS # Delete old recorded entry if new entry is a duplicate: setopt HIST_IGNORE_ALL_DUPS # Do not display a line previously found: setopt HIST_FIND_NO_DUPS # Dont record an entry starting with a space: setopt HIST_IGNORE_SPACE # Dont write duplicate entries in the history file: setopt HIST_SAVE_NO_DUPS # Share history between all sessions: setopt SHARE_HISTORY # Execute commands using history (e.g.: using !$) immediatel: unsetopt HIST_VERIFY ``` That was combined with [fzf](https://github.com/junegunn/fzf) to fuzzy-search through the history on `ctrl-r`. Configure your shell roughly like that and there you are: living the good shell life. Or you can use [Atuin](https://github.com/atuinsh/atuin), which I’ve been trying out for the last few weeks and have come to love. It’s a drop-in enhancement of your shell’s history functionality and not only gives you everything I described above – incredibly long shell history and fuzzy-search through it – but also syncing and backup (yup, need that) of shell history across multiple machines, filtering commands by machine, working-directory-specific history and probably 13 other things I forgot. It’s *very* nice. Highly recommend it. Whatever you use: make sure your shell history is recorded, make sure your shell history can grow ridiculously long, and get a fuzzy-search for it.