Tracking down a Zsh history data loss bug

ingve 58 points 18 comments August 15, 2026
michael.stapelberg.ch · View on Hacker News

Discussion Highlights (7 comments)

aclindsa

Nice work! I have felt like I lost zsh history before but never looked into it.

mmh0000

I have nearly a decade of zsh history. Reading that article I came to the conclusion that I may have been hit by that bug in the past but I haven’t noticed. Then I kept reading and the author mentions accidentally exporting HISTFILE[1] and I screamed in terror and ran to my computer as I realized a mistake I’ve been making for…ever. I am now both happy and sad I read this article. [1] https://github.com/stapelberg/configfiles/commit/32dcda0f49a...

TZubiri

Does zsh have that 2000 command limit by default? You can't expect much from a system that has those defaults, I'm all for traditions, but if I were to depend on a system for command history, it wouldn't be anything that reads a bash_history, a revolution is needed, not incremental optimizations P.s: what I do is set it to unlimited on both size and line count, but it's not a forensic grade audit trace, we'd need an OS, or ssh command logger, preferably one that writes to an external disk, but it can be to a root controlled file, definitely not to a user owned file. Security protects not only against attackers, but against bugs, a user's command history should not be deletable by user. Anything else is a wrong architecture that we are just carrying by inertia and laziness.

fragmede

Are people not just using http://atuin.sh these days?

myshapeprotocol

Tracking down subtle data loss edge cases in shell history internals requires absolute precision. Great debugging write-up.

nubinetwork

That's a bug? Happens to me with bash all the time, all I have to do is open 2 terminals at the same time... whichever one I close last is the one that writes its history. /shrug

chillpenguin

I ran into this a few years ago (or I ran into a very similar bug). I started backing up my history file regularly because it was so annoying to lose all that history. I'll keep backing it up, but this fix is appreciated!

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