Cron expressions schedule tasks in Unix-like systems. Each field follows: minute hour day-of-month month day-of-week.

* * * * * 
│ │ │ │ │
│ │ │ │ └── Day of week (0-7, 0/7=Sunday)
│ │ │ └──── Month (1-12)
│ │ └────── Day of month (1-31)
│ └──────── Hour (0-23)
└────────── Minute (0-59)

*: Every value
*/n: Every n intervals
a-b: Range a to b
a,b,c: List of values

Examples

Expression	Meaning
`* * * * *`	Every minute / Every 1 minute
`/2 * * *`	Every 2 minutes / Every even minute
`1-59/2 * * * *`	Every uneven minute
`/3 * * *`	Every 3 minutes
`/4 * * *`	Every 4 minutes
`/5 * * *`	Every 5 minutes
`/10 * * *`	Every 10 minutes
`/15 * * *`	Every 15 minutes / Every quarter hour
`/30 * * *`	Every 30 minutes / Every half hour
`0 * * * *`	Every 60 minutes / Every hour
`0 /2 * *`	Every 2 hours / Every even hour
`0 /3 * *`	Every 3 hours
`0 /6 * *`	Every 6 hours
`0 /12 * *`	Every 12 hours
`0 9-17 * * *`	Every hour from 9 to 17 / Hour range
`0 0 * * *`	Every day / Once a day / Every day at midnight
`0 1 * * *`	Every day at 1am
`0 2 * * *`	Every day at 2am
`0 8 * * *`	Every day at 8am
`0 9 * * *`	Every morning at 9am
`0 0 * * SUN`	Every Sunday at midnight
`0 0 * * MON`	Every Monday at midnight
`0 0 * * TUE`	Every Tuesday at midnight
`0 0 * * WED`	Every Wednesday at midnight
`0 0 * * THU`	Every Thursday at midnight
`0 0 * * FRI`	Every Friday at midnight
`0 0 * * SAT`	Every Saturday at midnight
`0 0 * * 1-5`	Every day of the week Monday through Friday at midnight
`0 0 * * 6,0`	Every weekend at midnight
`0 0 * * 0`	Every 7 days / Once a week / Weekly
`0 0 1 * *`	Once a month
`0 0 1 /2 `	Every other month
`0 0 1 /3 `	Every quarter
`0 0 1 /6 `	Every 6 months
`0 0 1 1 *`	Every year / Once a year