Something simple:
killall procname

Another way:
inside your script, create a temporary file that holds the current pid of your script. When you wish to terminate the process, use that as such: kill -9 `cat pidfile`

If you want something very specific and accurate:
- setuid() to another user which only runs that process (script)
- pkill -9 -u youruser
You can also use pkill to kill all processes using a certain terminal pkill -9 -t pts/1