Unlike DOS, you can run multiple commands in Linux at the same time.
Let's say you have a huge file to be sorted. Terminate the sort command with the ampersand (&) symbol. The shell will execute it in the background:
$ sort huge_file &
962 is the PID (process ID) of your job. It is executed in the
background, and the prompt is returned immediately.
If a process is executing for too long, and you didn't set it to run as a background process, here is how to get back the prompt and set this process to run in background.
1. Press CTRL-z to stop the executing process.
2. You will get the prompt. Now type bg and press ENTER.
3. The process will be executed in the background, and you will get back the prompt for other work.
4. If at any time you want this to continue to execute in the
foreground, press fg at the prompt and press ENTER.
See this link
for more info.