Bash/ZSH: Undoing 'disown'

Is there a way to 'reattach' a process to the shells job table after it it has been 'disowned'?

Edit: $SEARCHENGINE totally fails me. Doesn't look too good.

Considering how linux jobs and process ownership works, I'm afraid it's not really possible to re-own a process, without help from the adopting process.

A parent may 'disown' a child, which is then 'adopted' by the process named 'init'. System security prevents someone from grabbing someone else's processes. When you disown it, a process becomes someone else's (init's) to control. You as the 'user' could still kill the process, but you can't get it back. Attempting to coerce init to return your process is unlikely to work, as init doesn't even read mail.

As mean as it sounds, it really boils down to the answer of "Don't do that!".

While I assume this doesn't help anyone in the unfortunate situation of having disowned the wrong process, if you were to banish disown from your workflow and replace it with:

https://github.com/nelhage/reptyr

You would be able to reparent any process (i.e. move it inside screen).

All you need is reptyr. It lives on GitHub and has been packaged for Debian since Wheezy, and probably for other GNU/Linux distros, too. It will foreground your disowned process in the current terminal if you invoke it with its process ID (PID). So for example:

pgrep -f DISOWNED_PROCESS  # to find out the PID of the disowned process
reptyr PID                 # insert this PID here

Sorry, no. In principle, it would be possible, since disowning merely changes some shell internal state — it basically removes the process ID from a list, and it could be put back without too much hassle (you'd have to be a little careful in testing that the reattached pid is in the right session, but that's not insurmountable). But none of the usual shells (bash, ksh, tcsh, zsh) seem to have a way to re-add . (Though with zsh you can write to the jobstates, jobdirs and jobtext associative arrays; I don't know how much you can achieve that way.)

If you want the shell to send signals to the disowned process as it does for its owned subprocesses, you can write a stub job that waits until it receives a signal and sends the same signal to the disowned process. You can send SIGSTOP and SIGCONT to the disowned process to simulate Ctrl+Z and bg. None of this will be quite as convenient as re-owning.