Question

What is the best way to add and remove a hash symbol (#) from the crontab? I’d like to have a one liner that is capable of commenting all the cronjobs at once and if needed, uncomment them. It’s a CentOS distro.

I think the best option is to use ‘sed’ but I’m not entirely sure how it’d work with the crontab.

thanks.

Answer 1

You could do something like sed -e 's/^#//g' -i /etc/crontab … sed -e 's/^/#/g' -i /etc/crontab — assuming that your crontab file has no actual comments in it.

Safer to use a sentinel like s/^/#disabled: /g & s/^#disabled: //g

Even safer to put the “affected” cron entries into a file in /etc/cron.d/ and move that file in/out of the directory as-needed. mv /usr/local/etc/special-cron-jobs /etc/cron.d/ ; mv /etc/cron.d/special-cron-jobs /usr/local/etc

If you’re just trying to disable them all, you could also just stop cron itself, using

service anacron stop

(*anacron may not be right on CentOS?)