MOST cron files will have this disclaimer there already:
# DO NOT EDIT THIS FILE - edit the master and reinstall.
Never, ever, ever edit the cron files directly. There are multiple reasons for this:
Firstly, as you've seen, cron service has to be restarted after doing this
Secondly, this offers NO verification whatsoever that your cron is properly setup
Thirdly, it's the wrong way to do this
Use the crontab command. It's in everything from Linux to BSD. This will solve all 3 problems, and save frustration when dealing with improper crons.
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