||01-08-2008 02:53 PM
Mainly when I start a graphical user interface program from a terminal (say I need to pass some parameters to it, for example), but don't like to have the terminal wait there open all the time - or even worse, semi-accidentally close the terminal and also terminate the program started off it. In that case nohup allows closing the terminal and still having the program run.
Another somewhat similar thing I use, but mainly just with remote connections (and usually with irssi), is screen. It allows detaching the process, like irssi in my case, log out and later log back in and re-attach the very same process, thus not disconnecting anything "important".