emulates the detach/attach feature of screen

 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.