Kill Processes on UNIX-based Operating Systems

Even though Linux, OS X or other UNIX-based operating systems are very reliable nowadays, sometimes applications can become non-responsive. On other cases, an application is running in the background without any GUI. The conservative approach to quit one application by clicking on the X button ist here not possible.

Thank god there is the terminal, where all the launched programs can be listed. A program or applications runs usually as one or more processes. A process is just a term to describe a currently executed program.

With ps aux one can list all started processes in the terminal. Since it is a usually a large list, it makes sense use grep for filtering it for a specific application.

ps aux | grep [application name] 

Finding the process entry of a an application always gives a unique and so called process ID. With the command

kill [process ID]

the application can be finally terminated.