Hi, On Thursday 05 August 2004 06:46, C Hamel wrote:
On Thursday 05 August 2004 05:34, Carlos E. R. wrote: <SNIP>
Simple enough. Suppose you start at 00 hours. The next time, 18 hours later, would be at 18:00. The next time at 12:00 of the next day... you have an arithmetic series:
day hour lapse ---+--------+------ 0 00:00 00 0 18:00 18 1 12:00 36 2 6:00 54 2 24:00 72
So you get a three days cycle. How to put that into crontab: "I'll leave that as an exercise for the reader", translated as "I feel lazy" :-p
...
-- Cheers, Carlos Robinson
It can actually be fitted into a two-day cycle ...depending on the start time, I think. At any rate, I've elected to follow Scotty's advice & go your suggested route.
The least common multiple of 18 and 24 is 72, hence it requires a 72-hour (three-day) span to get exactly every 18 hours when only offsets within a 24-hour day (and day numbers) may be specified. I'm pretty unfamiliar with cron and haven't been following this thread all that carefully, but doesn't Carlos' approach require complete enumeration of the invocation intervals? Is there a way to get it to say "repeat this three-day pattern indefinitely"? Randall Schulz