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I am running a process which will take several hours. I would like to disconnect from the server, but I do not want to lose the output to the screen. Is there a way to bring the process back to my screen after I disconnect? It's a Python script that is running, and it is on Red Hat 6.3

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You can do that with screen, tmux or the classic combination of nohuping it and redirecting the output to a file. Plenty of answer about all of those on Super User. – Hennes Feb 12 '14 at 20:03
Any feedback as to why my question was downvoted? – Sugitime Feb 12 '14 at 20:03
Not my downvote, but I am guessing insufficient research. – Hennes Feb 12 '14 at 20:04
Nor my downvote...but just googling your own title to your question the first 2 results are StackExchange sites with the answer: – TheCleaner Feb 12 '14 at 20:05
None of the answer I found speak to how to pull a background process to screen if you didnt use the screen command when launching the command. – Sugitime Feb 12 '14 at 20:07
up vote 11 down vote accepted

Go back in time and smack yourself for not thinking ahead.

Then, fire up gdb against the running program, break into it and re-open STDOUT against a file. Then you should be able to background and nohup it without losing output.

(gdb) attach 18456
Attaching to process 18456
(gdb) call open("/tmp/myoutput.txt", 0102)
$1 = 3
(gdb) call dup2(3,1)
$2 = 1
(gdb) call close(3)
$3 = 0
(gdb) detach 
Detaching from program: /usr/bin/python2.7, process 18456
(gdb) quit

Then you can Ctrl-Z, bg, and disown the original process.

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@Sugitime All of the answers you found implicitly answer your question ("You can't go back in time." - usually). This answer offers you one option, and there are some OS-specific tricks you can do to attach to a different TTY (e.g. watch on FreeBSD, but I'm not sure what the Linux/RedHat equivalent is, if one exists. – voretaq7 Feb 12 '14 at 20:17
You can't go back in time, but you can rewrite history. :D – MikeyB Feb 12 '14 at 20:41
That works for me. The answer is you can't do what I want to do, but I can restart the script and do what I want to do if I start it a certain way. Thanks guys. – Sugitime Feb 12 '14 at 21:35
"I do not want to lose the output to the screen" <- I even got that for you. :D – MikeyB Feb 12 '14 at 21:41

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