Shell script help

pirhana · 11-20-2008, 04:12 AM

I have managed to write a script to backup my data to a remote server using rsync which works well. I'm very pleased with my achievements as I'm still new to this.

I run the script every night by cron as I get free bandwidth between midnight and 8am

I am now trying to get the script to shutdown the machine when it has finished, but simply adding "shutdown now" doesn't work as the system just hangs (tested from command line)

I am also wondering if it is possible to automatically kill the script at 8am if the backup has not finished, thus saving my paid-for bandwidth and leaving the rest of the backup until the next evening?

Any help is gratefully appreciated.

GlennsPref · 11-20-2008, 04:41 AM

Hi, to shutdown your system...halt

shutdown -h now

to reboot...

shutdown -r now

Hope this helps.

Regards Glenn

pirhana · 11-20-2008, 05:24 AM

Thank you, that works perfectly. Taking this a stage further, is there any way to test if the rsync finished or was stopped?
For example, when I run it from the command line, I sometimes need to end the script as it consumes my bandwidth, pressing Ctrl-C to terminate it now results in the shutdown
I have heard of exit codes in other scripting languages, is this available here?

rizwanrafique · 11-20-2008, 05:51 AM

I think you can run another job at 8am. That job should have a simple script that:

does something like

ps -ef|grep <your_script_name>|grep -v grep|awk '{ print $2 }'|xargs kill

pirhana · 11-20-2008, 09:58 AM

Quote:

Originally Posted by rizwanrafique

I think you can run another job at 8am. That job should have a simple script that:

does something like

ps -ef|grep <your_script_name>|grep -v grep|awk '{ print $2 }'|xargs kill

That is amazing code. I followed it through, section by section to understand what was happening each time (with help from the man pages) and I think it is brilliant. It works perfectly.

I'm just left with one part of my code to complete. Has anyone got any idea about the test on rsync to see if it finished naturally or if the script was terminated part way through? I only want to shutdown the machine if the script was run via cron and rsync completed. I don't want the machine shutting down when the second cron terminates the rsync script at 8am

pirhana · 11-20-2008, 01:10 PM

rizwanrafique

Thank you for your code. It works fine from the command line and also in a script:

Quote:

Originally Posted by rizwanrafique

#!/bin/sh
ps -ef|grep rsync.sh|grep -v grep|awk '{ print $2 }'|xargs kill

but when I tried to modify it to accept any script name from the command line, it fails. It simply says "Terminated" and the script continues to run:

Code:

#!/bin/sh

if [ $# -eq 1 ]; then
   ps -ef|grep $1|grep -v grep|awk '{ print $2 }'|xargs kill
fi

I'm calling it by entering:
./killprocess.sh rsync.sh
where killprocess.sh contains the code above and rsync.sh is running and needs to be terminated

As I said, I'm still new to this but learning fast. Apologies if I have made a school boy error

rizwanrafique · 11-28-2008, 04:49 AM

hmm when a script calls another script (or program) that script (or program) runs as the child for calling script. You need to kill both the parent and child manually.

I'm sure there are better ways finding out both parent and child process ids but one way is:

Code:

PPID=`ps -ef|grep <your_script>|grep -v grep|awk '{print $2}'`
CPID=`ps -ef|grep $PPID|grep -v grep|awk '{print $2}'|grep -v $PPID`

Now all you need to do is to kill both of them.

Second part of your original question:

I am not aware of any way to play with return codes to see if the rsync process has finished or not but we can implement that manually quite easily. This is how:

- create a lock fine before starting rsync in your script.
- when rsync finishes delete that file.

You can run a cron job to see if that file exists at 8am or not. If it does kill rsync process and the parent process. Delete the file. And do not shutdown. If the file doesn't exist just shutdown the machine.

Or just run a shutdown command after rsync in your script to shut it down straight after. And at 8am if the computer is still running then kill the rsync and the parent process :-)

GlennsPref · 11-28-2008, 04:22 PM

Hi, you might find these articles of use,

Jerry Peek has these articles on his own page too, available in .pdf format, ten (10) in all.

Linux Magazine, "Here’s the start of a series on little-known topics that wizards should know. Knowledge of the Harry Potter series not required."

Jerry Peek's
Wizard Boot Camp, Part One

http://www.linux-mag.com/id/4038

You guys are way ahead of me, but I just thought I'd share the resource, it covers a wide variety of things. I'm still working on it.

Cheers, Glenn