In Unix, you can stop any process that is running by pressing Ctrl+z. Suspending a command and moving it to the background is another story. If you want to do this, you must be familiar with Ctrl+z as well as another command: the bg command.
To turn any process into a background process, first press Ctrl+z to suspend the process if it is running and you did not enter an ampersand following the command. Consider the following example:
Ctrl+z + Stopped at 2
Here, the at command has been suspended and assigned job number 10.
The process ID (PID) (as shown with the ps command) is a number used by the kernel to keep track of every process running on the system. This is not the same as the job number. The job number will identify ...