How do I auto Logout my shell user in Linux after certain minutes of inactivity?

Linux bash shell allows you to define the TMOUT environment variable. Set TMOUT to automatically log users out after a period of inactivity. The value is defined in seconds. For example,

export TMOUT=120

The above command will implement a 2 minute idle time-out for the default /bin/bash shell. You can edit your ~/.bash_profile or /etc/profile file as follows to define a 5 minute idle time out:

# set a 5 min timeout policy for bash shell
TMOUT=300
readonly TMOUT
export TMOUT

Save and close the file. The readonly command is used to make variables and functions readonly i.e. you user cannot change the value of variable called TMOUT.

How Do I Disable TMOUT?

To disable auto-logout, just set the TMOUT to zero or unset it as follows:
$ export TMOUT=0
or
$ unset TMOUT
Please note that readonly variable can only be disabled by root in /etc/profile or ~/.bash_profile.

A Note About TCSH SHELL and OpenSSH Server/Client

SSH allows administrators to set an idle timeout interval in /etc/ssh/sshd_config file. TCSH user should use autologout variable. Please see our previous FAQ “Linux / UNIX Automatically Log BASH / TCSH / SSH Users Out After a Period of Inactivity” for more information.