To setup automatic logout of the inactive sessions in UNIX and Linux,
Set the TMOUT variable in /etc/bash.bashrc.local and /etc/profile.local

For Example:


TMOUT=<TIme in minutes>

TMOUT=0   is to set infinite time out or disable the automatic logout


To set this time out setting for a particular user:

Set the following in .profile or .bash_profile file which is available in each user home directory


For example:
export TMOUT=600