How to close "screen" session from a script?
 

I am using screen to start a LONG running script on my server over an ssh connection. This works fine. I can see that the script is continuing to run after I disconnect from the screen session using Ctrl-A d. When the script is complete I can reconnect to the screen session and manually terminate it.

I would like to be able to terminate the screen session at the end of the script. I tried issuing an exit command at the end of the script. That did NOT work. Any ideas?

TIA,

Ken

You could tack a "kill -9 PID" at the end of your script if you
can uniquely identify the screen instance you're firing up :}


Cheers,
Tink

Thanks Tinkster,

I think that would be rather easy for one script running. My plan is to initiate 4 parallel scripts so I will have to do some investigation. If I KNEW which script would end last I could have it iterate and kill all "screen" processes. Or I could run the scripts serially. I am not sure which would be faster. Basically I am using dd if=/dev/urandom of=(partition I want to clear)/bigfile to do a quick and dirty wipe of free space. Well at least quick compared to using sfill -l -l which I computed would take 12 DAYS! I guess I need to fill up more of the 5 GB of storage on my server with crap so I have less free space to wipe :rolleyes:

Ken

You could conceivably fire of all processes; check them in a while loop w/
a 1-second sleep, and kill screen if they're all gone ....
something like

No guarantee for completeness above ;D


Cheers,
Tink

An alternative to the above would be to utilise the $! Special Var http://tldp.org/LDP/abs/html/internalvariables.html and track the actual pids of the created processes.

Thanks folks! I allowed two processes to run overnight (14 hours) and based on the progress they made I think I will have to run sequentially. That will make things easier.

Ken

Out of curiosity: is this path to be wiped on an external USB device?

In answer to your curiosity... The system consists of:

A Dell Poweredge 400 SC server (Pentium 4; 2.33 GHz; 3 GB RAM) with the following hard drives (all SATA):

Western Digital Caviar Black 1 TB
Western Digital Caviar Green 1 TB
Western Digital Caviar Green 1 TB
Western Digital Caviar Green 2 TB

The green drives are low power consumption and a little slow but not that slow. I think the limiting factor is the CPU which is consumed 100% by dd.

I have had better results creating a file of say 1 GB with dd if=/dev/urandom and then copying the 1 GB files to the drive to be wiped from within a loop (cp to an incremented file name each time) until it runs out of space.

Ken

You could (to help the CPU) use a decent blocksize with dd ...

dd if=/dev/urandom of=/... bs=4096


Of course the problem may be the urandom usage.


[edit]
Scrap that - slow as. From urandoms man-page
So really, you probably just want to generate a 4096 or 2048
byte file, and slap that over the devices in the loop ;}
[/edit]



Cheers,
Tink

Thanks! Good point. urandom is really slow. I had at one time played with copying various size files of random data to fill free space. Larger files seemed to be faster.

Ken