The syntax for crontab entries is confusing at best. Fortunately, cron provides easy to read special strings for common cases.
If you want a job to run once a week your crontab would look like this:
And thats it!
@weekly in this case means
0 0 * * 0. Every Sunday at midnight.
You can check other crontab special strings with
man 5 crontab.
H/T Dorian KarterTweet