Tip: Bash remembering history across sessions (Shallow Thoughts)

Tip: Bash remembering history across sessions

Two separate friends just had this problem, one of them a fairly experienced Linux user:

You're in bash, history works, but it's not remembered across sessions. Why?

Maybe the size of the history file somehow got set to zero?

$ echo $HISTFILESIZE
500

Nope -- that's not it.

Maybe it's using the wrong file. In bash you can set $HISTFILE to point to different places; for instance, you can use that to maintain different histories per window, or per machine.

$ echo $HISTFILE
/home/username/.bash_history

Nope, that's not it either.

The problem, for both people, turned out to be really simple:

$ ls -l $HISTFILE
-rw------- 1 root root 92 2007-08-20 14:03 /home/user/.bash_history

I'm not sure how it happens, but sometimes the .bash_history file becomes owned by root, and then as a normal user you can't update your history any more.

So a simple

$ rm $HISTFILE

and you're all set -- history across sessions should start working again.

Tags: shell, bash, tips
[ 14:42 Nov 27, 2009    More linux/cmdline | permalink to this entry | ]