I know that I can have something run every five minutes in cron with a line like:
*/5 * * * * /my/script
What if I don't want it running at 12:00, 12:05, 12:10, but rather at 12:01, 12:06, 12:11, etc? I guess I can do this:
1,6,11,16,21,26,31,36,41,46,51,56 * * * * /my/script
...but that's ugly. Is there a more elegant way to do it?
Use your first schedule:
*/5 * * * * /my/script
And add this to the start of your script:
sleep 60
(Yes, this is a joke)
sean.bright's joke got me thinking... why not use...
* * * * * /my/script
...and within the script do this...
#!/bin/bash
export WHEN=`date '+%M'`
echo $WHEN
export DOIT=`echo "$WHEN % 5" | bc`
echo $DOIT
if [ $DOIT != 0 ] ; then
echo "ha ha ha"
fi
echo "done"
...a kludge... maybe, but as ugly as the crontab... I don't know.
1-56/5 * * * * /my/script
This should work on vixiecron, I'm not sure about other implementations.
I'd create a new script "delaystart" that takes a sleeping period as first parameter and the script to run as the rest. I'd make the script check the crontab line for the line with the script and only start the script if the line is not commented out. That makes it reusable, and ps won't report the script as running when it really isn't.
#!/bin/bash
sleeptime=$1
sleep ${sleeptime}
shift
if ( ! crontab -l | grep -e '#.+delaystart '${sleeptime} $* ) then
$*
fi