UNIX FAQ Version 2.1 92/12/04 -- Question 4.10

Is it possible to reconnect a process to a terminal after it has been disconnected, e.g. after starting a program in the background and logging out?

Most variants of Unix do not support "detaching" and "attaching" processes, as operating systems such as VMS and Multics support. However, there are two freely redistributable packages which can be used to start processes in such a way that they can be later reattached to a terminal.

The first is "screen," which is described in the comp.sources.unix archives as "Screen, multiple windows on a CRT" (see the "screen-3.2" package in comp.sources.misc, volume 28.) This package will run on at least BSD, System V r3.2 and SCO UNIX.

The second is "pty," which is described in the comp.sources.unix archives as a package to "Run a program under a pty session" (see "pty" in volume 23). pty is designed for use under BSD-like system only.

Neither of these packages is retroactive, i.e. you must have started a process under screen or pty in order to be able to detach and reattach it.