Managing Processes in Bash on Linux

To send a running process to the background, you first need to pause it:

Ctrl-z

Get the number of the paused job:

jobs -l

then send it to the background with the bg command:

bg %jobnum

You can bring a process back to the foreground with the fg command:

fg %jobnum

To keep a process from being interrupted when the terminal session ends, you need to run it inside screen. But what do you do if the process has already been running for a few hours with no end in sight? Killing it and losing all that time feels like a waste.

Don’t lose heart - you can send the process to the background using what’s described above, then cut all ties with it:

disown -h %jobnum

Now you can safely close the terminal window, the running command will keep going without you.

You can check whether a job is still running with the ps utility:

ps -aux |grep %process_name%

The second column is the process’s PID.

You can also use the kill utility to control processes:

• kill -9 PID - stops execution
• kill -20 PID - pauses (suspends) execution
• kill -18 PID - resumes a paused process.