[SOLVED] How do I keep a Perl script running on Unix after I log off?

Issue

I have a script that takes a lot of time to complete.

Instead of waiting for it to finish, I'd rather just log out and retrieve its output later on.

I've tried;

at -m -t 03030205 -f /path/to/./thescript.pl

nohup /path/to/./thescript.pl &

And I have also verified that the processes actually exist with ps and at -l depending on which scheduling syntax i used.

Both these processes die when I exit out of the shell. Is there a way to keep a script from terminating when I close the connection?

We have crons here and they are set up and are working properly, but I would like to use at or nohup for single-use scripts.

Is there something wrong with my syntax? Are there any other methods to producing the desired outcome?

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EDIT:
I cannot use screen or disown - they aren't installed in my HP Unix setup and i am not in the position to install them either

Solution

This is just a guess, but something I've seen with some versions of ssh and nohup: if you've logged in with ssh then you may need to need to redirect stdout, stderr and stdin to avoid having the session hang when you exit. (One of those may still be attached to the terminal.) I would try:

nohup /path/to/./thescript.pl > whatever.stdout 2> whatever.stderr < /dev/null &

(This is no longer the case with my current versions of ssh and nohup - the latter redirects them if it detects that any is attached to a terminal - but you may be using different versions.)

Answered By - Mark Longair