Jobs: How to Use Jobs

Introduction link

Jobs allow you to have multiple tasks running in parallel. The advantage is that you don’t need to open multiple shells to launch multiple applications.

Usage link

The jobs command allows you to see exactly what is running in the background:

  jobs
  

  [1]  + running    tail -f /var/log/syslog
  

Here we can see that there is a tail -f running.

If you want to launch a command so that it becomes a job (running in the background), start it like this:

  tail -f /var/log/syslog &
  

• If you forgot the ‘&’ symbol at the end of your command, no worries, there is a way to fix it. Press ‘Ctrl+Z’ (^Z) to pause the current command, then type ‘bg’ which means background.

• You can check the status of your command with the jobs command. Then, if you want to bring back the command you just put in the background, simply use the fg command which means foreground.

• If you want to exit your shell, you will lose all your ongoing jobs. To prevent this from happening, you need to launch a nohup like this:

  nohup my_command &
  

Again, if you’re forgetful and forgot the nohup, there’s a solution. After launching your command, you need to:

• Press Ctrl+Z (^Z)
• Type: bg
• Then type: disown

This will do the equivalent of the previous command.

• To kill a job, for example the first one:

  kill %1
  

To see what’s happening with background processes:

  lsof -p$!