u can use these shortcuts for your crontab jobs
this table is going to show you what you can use to make cronjobs

Instead of the first five fields, you can use any one of eight special strings. It will not just save your time but it will improve readability.

Special stringMeaning
@rebootRun once, at startup.
@yearlyRun once a year, “0 0 1 1 *”.
@annually(same as @yearly)
@monthlyRun once a month, “0 0 1 * *”.
@weeklyRun once a week, “0 0 * * 0″.
@dailyRun once a day, “0 0 * * *”.
@midnight(same as @daily)
@hourly Run once an hour, “0 * * * *”.