User cronjob via crontab is hanging

JockVSJock · 06-16-2009, 06:21 PM

Running Ubuntu 8.10 and have created the following user cronjob that backs up all my data in my home directory:

Code:

#!/bin/bash
# backup data on a daily basis via rsync and a cron job

echo backup started `date` >>/home/cmmiller/backup/backuplog
rsync -avh /home/cmmiller/ /media/Linux_ext3/
echo backup complete `date` >>/home/cmmiller/backup/backuplog
echo du -csh /media/Linux_ext3 | df -h /media/Linux_ext3 >>/home/cmmiller/backup/backuplog
echo

This past weekend I cleaned up my home directory and then deleted all of the files on the external hard drive so it would display the data as it now appears in my home drive.

For some reason after doing this, the cron job now hangs. I can look at top and see various processes running. I kill the processes and the cron job completes.

I ran the cron job for the hell of it from the command line and didn't have the same issue, so I'm not sure what is going on...I am writing to a log to check the progress the next day, however it isn't telling if there is an issue or not.

thanks

grepmasterd · 06-16-2009, 06:36 PM

this line confuses me

Code:

echo du -csh /media/Linux_ext3 | df -h /media/Linux_ext3 >>/home/cmmiller/backup/backuplog

can you tell me what you're trying to do here? - it looks broken

maybe you mean:

Code:

du -csh /media/Linux_ext3 >>/home/cmmiller/backup/backuplog
df -h /media/Linux_ext3 >>/home/cmmiller/backup/backuplog

??

JockVSJock · 06-16-2009, 06:43 PM

Hmmm...That is a pipe, because I want to see in the log on the same line the space used Vs space free...

I can tweak it and have it run overnight and report back the results...

thanks

grepmasterd · 06-16-2009, 06:49 PM

well you're piping the string "du -csh /media/Linux_ext3" (not the results of the command, which doesn't really matter because either would be wrong) into 'df', which is meaningless. the result of that is what is getting written to your log.

yes, clean up your script and see if it works better.

JockVSJock · 06-17-2009, 06:25 AM

Changed the | to ; and its not hanging anymore.

thanks

grepmasterd · 06-17-2009, 09:55 AM

here's a helpful trick. you can put your code in a block and redirect the output from the whole block to your log file in one step. that way you don't have to worry about getting all of the redirects in the right place. within the block you can just write script as normal.

Code:

#!/bin/bash
# backup data on a daily basis via rsync and a cron job

{
echo backup started `date`
rsync -avh /home/cmmiller/ /media/Linux_ext3/
echo backup complete `date`
du -csh /media/Linux_ext3
df -h /media/Linux_ext3
echo
} >>/home/cmmiller/backup/backuplog

JockVSJock · 06-17-2009, 06:23 PM

Cool, didn't know this, thanks for sharing.

bigearsbilly · 06-18-2009, 06:21 PM

you can also do it like so:

Code:

#!/bin/sh

exec > log
exec 2>&1     # errors same place


cat <<EOF
blah
blah
blah
$(date)

EOF
cat flap

or to append of course:
exec >> log

JockVSJock · 06-18-2009, 09:41 PM

Thanks for the help, I'm more of a sys admin/network guy...so I only script when there is a need.