Shell tip: Clear the command history and screen when you log out
For security reason you may want to clear the history file and the screen when you hit CTRL+D or type logout command as you don’t want to left content on screen (i..e avoid an information leak). Some Linux distro may clear the screen but others do not clear the screen when you logout.
When a login shell exits, bash reads and executes commands from the file ~/.bash_logout, if it exists. Basically you can use this file as the individual login shell cleanup file, executed when a login shell exits.
There is a simple solution to this problem, open your ~/.bash_logout file:
$ vi ~/.bash_logout
Append any one of the following command:
/usr/bin/clear_console
OR
/usr/bin/clear
You can also reset your history by appending following commands:
>~/.bash_history
>~/.mysql_history
sync;
First one will clear bash history and 2nd command will clear mysql command history using shell REDIRECTION operator >.
You may also be interested in other helpful articles:
- Howto: Linux Refresh all or an X screen Kde-Gnome desktop
- setsid: Keep Linux / UNIX program running while you logs out
- Increase security by Locking Admin screen/console
- Linux screen command tutorial / how to
- Howto: Linux kill and logout users
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The >~/.bash_history thing seems a slightly odd way of doing things, why not put “unset HISTFILE” in your .bashrc file, since .bash_logout will be run about the time .bash_history is written, so it may (though probably not) end up wiping the file before it’s written.
Or what I prefer to do, rm .bash_history and then :
ln -s /dev/null .bash_history
maybe history -c is an option…
>ln -s /dev/null .bash_history
sounds good idea
>maybe history -c is an option…
never thought of that, good idea
Appreciate your posts!
really this is very useful for me
> maybe history -c is an option…
I like it.
I’ve typically used:
HISTFILE=/do/not/use/$RANDOM/$RANDOM
> why not put “unset HISTFILE” in your .bashrc file, since .bash_logout
> will be run about the time .bash_history is written [snip]
Similar idea, but IIRC I’ve had problems with unsetting the HISTFILE — but that was probably ~15 years ago under Korn shell.
I also tried a touch-then-delete approach in my profile, I think that one worked fine, but the $RANDOM is my default.
Incidentally, I try to always do this for root, since on rare occasions passwords are on the command line.
ever heard of kill -9 $$ ?
It logs you out and clear the history.
It seems to kill bash, echo $$ gives you the bash PID
A friend of mine showed me this once, but I never completely get how it works, if someone can explain, please do so…
This is the Wright and the Best OPtion to clear the command History
history -c
Thanks shaff, It works
Hi,
history -c will clear the entire bash history.
To only clear the current session history use:
history -r.
you are a genius shafe