As you may know that we can use screen command to start a session when you SSH that allows you to run a few long commands that won’t terminate when the session is disconnected.

However, if you forget to do so, and you have a long-running application running, and we can follow the steps to put it in the background, which won’t be killed when the session is ended.

Let’s prepare a long-running script/application in BASH:

1
2
3
4
5
6
7
8

$ cat someApplication
#!/bin/bash
while :
do
    echo print some output
    sleep 2
done
$

$ cat someApplication
#!/bin/bash
while :
do
    echo print some output
    sleep 2
done
$

Pause the Current Running Program

You can press Ctrl + Z – which will pause the current running program:

1
2
3
4
5
6
7
8
9

$ someApplication
print some output
print some output
print some output
..
..
Ctrl + Z <- Keyboard interrupt
[1]+  Stopped                 ./someApplication
$

$ someApplication
print some output
print some output
print some output
..
..
Ctrl + Z <- Keyboard interrupt
[1]+  Stopped                 ./someApplication
$

Put the Suspended Program in Background

Then, we need to run bg to put the suspened program in the background. You will see the script printing output and you will have access to the prompt.

1
2
3
4

$ bg
[1]+ ./someApplication &
$ print some output
$ print some output

$ bg
[1]+ ./someApplication &
$ print some output
$ print some output

Then Disown the Program

Then, we need to run disown command to return the ownership of the program, which should make the program keep running in the background until being killed or host rebooted.

1
2

$ disown
$

$ disown
$

Close the current SSH session, then login back:

1
2

$ ps augx | grep someApplication
helloacm   29695  0.0  0.0  15244  3192 ?        S    19:31   0:00 /bin/bash ./someApplication

$ ps augx | grep someApplication
helloacm   29695  0.0  0.0  15244  3192 ?        S    19:31   0:00 /bin/bash ./someApplication

As you can see, the application is still alive. However, we cannot bring the application back to foreground as we already lost the ownership by issuing the disown command. We can kill it to terminate it although.

1

$ kill 29695

$ kill 29695

–EOF (The Ultimate Computing & Technology Blog) —