TLDR: use fg to bring the process back to the foreground.

Suspending

Suspending a process is actually pretty useful when you intend to do it.

Imagine you have a long running process. Maybe you’re running a backup, or uploading to a remote server. You don’t want to kill the process, you just want to pause it temporarily so you can get something else done.

Pressing CTRL+Z will suspend the current process, freeing up your terminal so you can work on something else. When ready to return, run fg.

So what exactly does CTRL+Z do?

It sends a TSTP signal to the process currently in the foreground. This signal is designed to “politely” suspend a process. As this singal isn’t forceful, processes can choose to ignore it.

Once suspended, the process will await the CONT signal to continue.

Bring it back!

The fg command brings a suspended process back to the foreground with a CONT signal. If you have multiple suspended processes, you’ll need to specify which process you want to bring back.

To see all suspended processes, run jobs -l to list them out. The output would look something like this:

[4]+ 6161 Stopped       ping barnz.dev

Choose from the list of processes by either the index in the list, or the command. For example, both of these will bring the ping process back to the foreground:

fg %4
fg %ping