Stopped jobs mean that you have started some processes (programs usually) that are in "stopped" state, and if you try to issue exit
your shell (bash commonly) notices you that there are processes that haven't ended (and if you exit, they get killed because they're child processes of your login). The second exit
works because after the first one you're already informed, and issuing second exit tells your shell you know the processes get killed and don't care about it, but want to exit. If it prevented you from exiting, and instead always prompted you, you might get into small trouble if the processes were persistent
To see what processes there are (stopped, running or whatever) you usually use
to get a list of them. Then, possibly depending on the shell you use (I use bash almost all the time) you deal with the processes if you like to. To kill a process by it's process id (pid):
is the id number of the process (get from ps
for example). However if you use jobs
to get the list, you may often refer to the processes using percent-number:
the above would try to kill the program that was the first-started in the list (2 for second etc.); the numbers should be told when using jobs command. If the process is persistent, you may try to kill it instantly (without allowing the process time to exit cleanly):
and so on. Read
for more information (I'm not sure if all those have manpages, but hope so).
For your information, you may start a process in the background like this:
meaning that it's not visible in your terminal (&-mark) but it's running in the background. After this if you stop it using CTRL-Z, or if the process needs to get more information (i.e. it asks you "Password: " or something, so it cannot continue it's run before you've interacted with it -- for example), it's stopped. That means the process is still alive, and possibly in the background, but not running at the moment. To get a process from the background to foreground (so you can see it, and maybe continue it's run) you use -- for example, like above --
and refer to the second started program with %2 etc.