@hourly vs 0 * * * * - Cron - How to run jobs hourly, but at different times

From crontab(5):

@hourly: Run once an hour, ie. "0 * * * *".

So it's strictly the same.

To run a job at a varying point in the hour (or multiple jobs, to spread the load) you can sleep for a random amount of time before starting the job:

@hourly sleep $((RANDOM / 10)); dowhatever

This sleeps for up to 3276 seconds (nearly an hour), then runs the job. So every time cron starts the job, it waits a different amount of time before actually starting.

@hourly is an exact synonym of 0 * * * * in crontab, there is no difference. @hourly is a special string representation for 0 * * * *.

From man 5 crontab:

string         meaning
------         -------
@hourly        Run once an hour, "0 * * * *".

Just to note, there are 8 special strings in total supported by the cron i have, Vixie Cron.

Just wanted to share Jenkins Cron/Build Periodically Methodology. Would be nice to see something like this in regular Cron where H(hash) was an option

Examples:

# every fifteen minutes (perhaps at :07, :22, :37, :52)
H/15 * * * *
# every ten minutes in the first half of every hour (three times, perhaps at :04, :14, :24)
H(0-29)/10 * * * *
# once every two hours at 45 minutes past the hour starting at 9:45 AM and finishing at 3:45 PM every weekday.
45 9-16/2 * * 1-5
# once in every two hours slot between 9 AM and 5 PM every weekday (perhaps at 10:38 AM, 12:38 PM, 2:38 PM, 4:38 PM)
H H(9-16)/2 * * 1-5
# once a day on the 1st and 15th of every month except December
H H 1,15 1-11 *