Moving an already-running process to Screen

Question

My office job routinely sees me connected to a Linux box via VNC.

Sometimes I start a remote job on the console, and realize later that it runs much longer than expected. (Should have started that one under Screen in the first place...)

I don't want to keep my workstation running overnight just to keep the VNC session open; I would like to move that already-running remote job into a Screen session (on the remote box), so I can power down the workstation (and reconnect next morning).

How can this be done, if at all?

Answer 1

Have a look at reptyr, which does exactly that. The github page has all the information.

reptyr - A tool for "re-ptying" programs.

reptyr is a utility for taking an existing running program and attaching it to a new terminal. Started a long-running process over ssh, but have to leave and don't want to interrupt it? Just start a screen, use reptyr to grab it, and then kill the ssh session and head on home.

USAGE

reptyr PID

"reptyr PID" will grab the process with id PID and attach it to your current terminal.

After attaching, the process will take input from and write output to the new terminal, including ^C and ^Z. (Unfortunately, if you background it, you will still have to run "bg" or "fg" in the old terminal. This is likely impossible to fix in a reasonable way without patching your shell.)

Answer 2

As you're using Linux, what about using retty inside the newly launched screen process?

$ screen -S my_process
$ retty $(pgrep my_process)
/redraw

HTH

cheers,

Answer 3

You cannot do this, easily. I'd suggest making it a habit to start screen as the first thing you do after opening a console.

However, for your actual problem, there's another thing you could try: after having launched your job from the terminal, background it by typing ctrl-z and then bg. After that, detach the job from it's parent shell; in bash you'd do disown -h %<jobid>. After that, you can safely close the terminal and the job will continue running.

Answer 4

Why do you care about shutting down the VNC client? The server session remains running.

VNC is a lot like screen in that respect.

Answer 5

Better working, yet more sophisticated, methods were researched in Moving a process to another terminal blogpost.