Sometimes you will come across a situation where you need to make absolutely sure that program x is not being accidentally closed in anyway. This is where the nohup command comes in. When you add the command in front of your program/script of choice then the process will keep on running on the background even after you have seemingly closed the program in a regular way.
Here is an .xinitrc line, which uses nohup:
nohup stalonetray &
Now, if I would want to quit the stalonetray completely I would open a terminal and write:
sudo killall stalonetray