Close a listening port opened by hanging ssh tunnel

This concerns only the port opened by an SSH tunnel. For other ports, follow this instruction.

$ who
dpa pts/0 2013-08-05 12:51 (10.216.6.218)
dpa pts/1 2013-08-06 11:38 (10.216.6.218)
dpa pts/2 2013-08-06 10:27 (10.216.6.218)

$ netstat -an | grep 8191
tcp 0 0 127.0.0.1:8191 0.0.0.0:* LISTEN -

$ skill -9 -t pts/1
$ netstat -an | grep 8191

The skill command will kick out a logged-in user. In this case it will close an SSH session by force.