Kill Processes
To kill a process or application in Linux is quite simple, you can do it based on ID or name.
Overview
To get an overview I often use the top command using Ubuntu.
This is possible right out of the box, without installing any third-party software.
You can also use the ps -ef command to get something quite like it.
Kill by ID
To kill by the specified ID, you simply use the kill command.
sudo kill <pid>Kill by Name
To kill by name, you use the pkill command.
sudo pkill <name>