Add a line to crontab using sed

crontab -l | sed -e '$G;$s-$-'"$CRON_MINS $CRON_HOUR"' * * * /usr/bin/command >/dev/null 2>&1-' | crontab -
I needed to add a line to my crontab from within a script and didn't want to have to write my own temporary file. You may find you need to reload the crond after this to make the change take effect. e.g.: if [ -x /sbin/service ] then /sbin/service crond reload else CRON_PID=`ps -furoot | awk '/[^a-z]cron(d)?$/{print $2}'` if [ -n "$CRON_PID" ] then kill -HUP $CRON_PID fi fi The reason I had CRON_HOUR and CRON_MINS instead of numbers is that I wanted to generate a random time between midnight & 6AM to run the job, which I did with: CRON_HOUR=`/usr/bin/perl -e 'printf "%02d\n", int(rand(6))'` CRON_MINS=`/usr/bin/perl -e 'printf "%02d\n", int(rand(60));'`

-1
By: JohnGH
2010-01-07 11:00:05

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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