Pkill

pkill – Kill user session and forcefully logout of the system.

Use the who command to see list of logged in users as follows:

# w

OR

# who

Sample outputs:

root     pts/0        Jul 29 13:53 (10.1.6.120)
nixcraft pts/1        Jul 29 12:30 (10.1.6.121)
sailee   pts/2        Jul 29 12:33 (10.1.6.121)

To force and logout nixcraft and sailee user, enter:

# pkill -KILL -u nixcraft
# pkill -KILL -u sailee

Alternatively, just try bash and friends kung-fu and save time:

### warning must be run as root or via sudo ###
who | awk '!/root/{ cmd="/sbin/pkill -KILL -u " $1; system(cmd)}'

OR

### warning must be run as root or via sudo ###
### Safe version :) ###
who | awk '$1 !~ /root/{ cmd="/sbin/pkill -KILL -u " $1; system(cmd)}'