In order to kill a process that is stuck you can issue pkill. In this case:
pkill firefox
If the process still won't die then you need to add the flag -9. I.e:
pkill -9 firefox
In order to kill a process that is stuck you can issue pkill. In this case:
pkill firefox
If the process still won't die then you need to add the flag -9. I.e:
pkill -9 firefox