Example:
/usr/bin/idleout 60
here is the man page for idleout:
idleout -- log out idle users
Syntax
======
idleout [ minutes | hours:minutes ]
Description
===========
The idleout command monitors line activity and logs out users whose terminal
remains idle longer than a specified period of time. Minutes are assumed;
if a colon appears in the number, hours are assumed.
The utility uses a default file, /etc/default/idleout, to indicate the
interval a user's terminal may remain idle before being logged out. This
file has one entry:
IDLETIME=time
The time format is identical to that used on the command line. The time
specified in the default file is overridden by idletime if idletime is
specified on the command line. Note that, if idletime is zero, no
monitoring takes place and idle users are not logged out. You can either
run idleout from the command line, or, to have continuous coverage, you
must add the program name in /etc/rc2.d/S88USRDEFINE to see to it that the
program is run each time the system is rebooted.
Files
=====
/etc/default/idleout
/etc/utmp
/etc/wtmp