Automatic Logout incase of inactivity.

Consider a scenario where you are working on so many linux terminal at a time.
In this scenario ,It may not advised to open the terminal for a day long .
This can be avoided in following way.

Following command when executed on terminal result a session to log off in case of 5 minutes of inactive session.
#export TMOUT=300

this can be included in /etc/profile file to implement it against every user. However this can be override if users profile file has some other values in it.

This can be avoided by putting readonly TMOUT=300 in /etc/profile file.

Note:
not tested for shells other than Bash or Korn.

Please refer following thread for more information.
http://www.linuxquestions.org/questions/showthread.php?p=4099036