Problem
Want to kill all processes, for a specific user.
Solution
This command will send a -KILL signal, equivalent to minus 9:
pkill -KILL -U username
Example
So to kill all processes owned by username marcus:
pkill -KILL -U marcus
If you issue kill -l – that is kill minus L, it will show all the symbol to numeric codes. Although you can just use numeric with pkill:
pkill -9 -U marcus