[arno_v]

I will try this, recently mine got truncated (don't know why) and it's super annoying.

[euoia]

If you have time machine, you may be able to recover the old history file.

[saagarjha]

I lost two history files to the ether, and repaired several more with Time Machine before I got fed up with dealing with this anymore. (I still have Time Machine enabled, but I haven't had to restore my bash history from it in years.)

[mmsc]

For some reason, macOS will truncate your bash_history if your free space on your drive is low. No idea why they chose to truncate a small text file.