Linux - Starting a process at background

In order to start a Linux process on the background, just put & at the end of the command

For example, to run a sleep command at the background, you do the following

sleep 10000 &

The above will sleep for 10s at the background.

When this command being executed, it will return a PID for the background process.

So, to kill the background process, you can use kill command to kill the background process

kill -09 XXXX

where XXXX is the PID returned for the background process.

Below is a detail screenshot.