run commands persistently over ssh

lawson · 02-15-2010, 08:38 PM

I would like to log in to a remote machine via SSH, start a process running, and then log out, leaving the remote process running. This seems like an obvious thing to do, but I can't figure out how to do it! The problem is that any process that I start seems to be "attached" (sorry, I don't really know the correct terminology here) to my SSH login shell, and so when I log out the process is killed. Ctrl+Z bg doesn't seem to do it, either. Is there a way to do this? It seems that there must. Thanks!

neonsignal · 02-15-2010, 08:53 PM

You can use nohup to start a command that will not hangup when the shell exits. In this example, output goes to output.log, errors to error.log:

Code:

nohup foo >output.log 2>error.log &

You can use the bash command disown to do the same thing with an existing process, eg:

Code:

foo >output.log 2>error.log &
disown

Or you can use GNU screen to create a terminal that can be disconnected/reconnected at will.

talla · 02-16-2010, 05:21 AM

screen is very nice.

just type "screen". A "shell in shell" will open. Start your process, then press Strg + ALT + D to detach your screen and return to your "usual shell".

When you log in again use "screen -r" to switch back to you running process.

(you can even start multiple shells in screen using Strg + A + C and switch between them using Strg + A + N)

And moreover, you can share a screen with other users for remote interaction
http://www.linux.com/archive/feed/56443

Cheers,
talla