Sometimes out of necessity, we have more than one user logged into the same unix account. I like to repeat previous commands. Since the commands for all users logged into this account go into a common history, this can be a problem. if I'm not careful I can run a command I don't intend to run.

Yesterday I accidentally ran an "exit" command--annoying, but not serious. However, it hit me that if the other person used an "rm" command it could have been very serious.

Does anyone know if there's a way to turn off the common history and only have commands in the history from that login session?

Much appreciated,
Vince

env variable HISTSIZE for ksh

I think Optimus_P meant HISTFILE rather than HISTSIZE. See the Korn Shell FAQ.

Bingo! That's exactly what I'm looking for. Thanks a lot Perderabo.

If this is an application ID, I have a solution for you. This is not my script, but I offer it to you.

Set your login shell to /usr/bin/nologin for this shared user.
Next, login as yourself then su - username.

Use a script, put this in your .profile for the application, like this one below to keep track of individual history files.

When you su to root or an application ID this is great! Remember put this in your .profile for root or application .profile.

#***************************************
# sets .sh_hist file to id of user

if [ "`tty`" = "/dev/console" ]
then
REAL=console
else
REAL=`logname`
fi


HISTFILE=$HOME/.sh_$REAL
export HISTFILE
HISTSIZE=1000; export HISTSIZE
#****************************************

Another approach is:

HISTFILE=$HOME/.histfile.$$

which create unique histfile for each login shell. In this case, problem is that user don't see his history from previous log-in and you have to delete this files during log-out process.

If you use csh [and clones], put

rm $HISTFILE in your .logout

If you use sh [and clones], try something similar in your .profile

trap 'rm $HISTFILE; exit' NULL