How to stop background jobs?

Stopping Background Jobs in Linux

In the Linux operating system, when you run a command or a program, it can either run in the foreground or in the background. Foreground processes are those that take up the current terminal session, while background processes run without occupying the terminal. This can be useful when you want to execute a long-running task without tying up your terminal.

To start a process in the background, you can append the & symbol at the end of the command. For example, to run the sleep command in the background for 60 seconds, you would use the following command:

sleep 60 &

This will immediately return you to the terminal prompt, allowing you to continue using the terminal while the sleep command runs in the background.

Listing Background Jobs

To see the list of background jobs running in your current session, you can use the jobs command:

$ jobs
[1]  + running    sleep 60 &

This shows that there is one background job running, with the job number [1].

Stopping Background Jobs

There are a few ways to stop background jobs in Linux:

Terminating the Job: You can terminate a background job using the kill command, followed by the job number. For example, to stop the job with number [1], you would use:
```
kill %1
```
This will send a SIGTERM signal to the process, requesting it to terminate.
Suspending the Job: Instead of terminating the job, you can also suspend it temporarily using the fg (foreground) command. This will bring the job to the foreground, allowing you to interact with it. To resume the job in the background, you can press Ctrl+Z, which will suspend the job and return you to the terminal prompt.
```
$ fg %1
sleep 60
^Z
[1]+  Stopped                 sleep 60
```
Killing the Job: If the job doesn't respond to the SIGTERM signal, you can use the kill -9 command to send a SIGKILL signal, which will forcibly terminate the process.
```
kill -9 %1
```

By understanding how to manage background jobs in Linux, you can more effectively run long-running tasks without tying up your terminal session. This can be especially useful when working on complex projects or running resource-intensive operations.

graph TD A[Run Command] --> B[Append "&" to run in background] B --> C[Use "jobs" command to list background jobs] C --> D[Terminate job with "kill %"] C --> E[Suspend job with "fg %", then press Ctrl+Z to resume in background] C --> F[Kill job with "kill -9 %"]