Sometimes, when you start a program from the terminal, closing the terminal will also close the program. Even if you start the program in the background. vlc does this. E.g. Start vlc with vlc &, close the terminal and vlc will also close.
To prevent this you can detatch the process from the terminal using the nohup command:
nohup vlc &
References: How do I detach a process from Terminal, entirely?
