Shell tip: Clear the command history and screen when you log out

by Vivek Gite · 12 comments

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 >.

Featured Articles:

Want to read Linux tips and tricks, but don't have time to check our blog everyday? Subscribe to our daily email newsletter to make sure you don't miss a single tip/tricks. Subscribe to our weekly newsletter here!

{ 12 comments… read them below or add one }

1 dbr 05.15.07 at 10:12 pm

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

2 J 05.16.07 at 8:40 am

maybe history -c is an option…

3 vivek 05.16.07 at 9:40 am

>ln -s /dev/null .bash_history
sounds good idea

>maybe history -c is an option…
never thought of that, good idea :)

Appreciate your posts!

4 naveenvasireddy 05.21.07 at 4:56 am

really this is very useful for me

5 NVRAM 05.24.07 at 3:19 pm

> 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.

6 jeff 09.27.07 at 6:27 pm

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…

7 SHAFE 04.02.08 at 2:01 pm

This is the Wright and the Best OPtion to clear the command History

history -c

8 Shankar 05.23.08 at 4:50 am

Thanks shaff, It works

9 Harka 05.23.08 at 12:15 pm

Hi,

history -c will clear the entire bash history.
To only clear the current session history use:
history -r.

10 erica 08.11.08 at 10:09 am

you are a genius shafe

11 Kumar Chetan Sharma 11.20.08 at 7:49 am

even after running clear or history -c, which I find is the best option to add to ./bash_logout, I can still scroll my putty screen and see what all I have done. Is there any way to completely erase this information.

12 Vinnie 07.15.09 at 3:38 pm

Kumar asked about clearing the information from his putty window.

To do so -
1. Right click on the top bar of the putty window
2. A Context menu will appear
3. Select “Clear Scrollback”

This will erase all details of your session from putty’s scrollback buffer.

Leave a Comment

You can use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Previous post:

Next post: