dtach

dtach is a tiny program that emulates the detach feature of screen, allowing you to run a program in an environment that is protected from the controlling terminal and attach to it later. dtach does not keep track of the contents of the screen, and thus works best with programs that know how to redraw themselves.

dtach does not, however, have the other features of screen, such as its support of multiple terminals or its terminal emulation support. This makes dtach extremely tiny compared to screen, making it more easily audited for bugs and security holes, and also allows it to fit in environments where space is limited, such as on rescue disks.