Cron Expression to English Translator

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	Cron Expression to English Translator (crontab.guru)
	3 points by augustflanagan 2671 days ago

1 comments

ColinWright 2671 days ago

There was something like this a while back. It was discussed at the time[0] and had some serious faults. The link[1] no longer works.

So I thought I'd pull out one of the examples from my crontab that didn't work for that one and try it on this one:

    6/2-59 * * * *

Nope, doesn't work.

[0] https://news.ycombinator.com/item?id=8122129

[1] http://www.cronchecker.net/

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encoderer 2671 days ago

Hi Colin,

I'm curious, what is the expected behavior here? `6/2` would say "every 2nd minute, starting from minute 6". You can combine a range and a step like this: `6-30/2` but I'm not sure how to parse your step with a range.

Is it possible crontab.guru is exposing a bug in your crontab that your version of cron just happens to be tolerant of?'

Edit: You can see in this line how a range and step is used in a normal for loop in the cron scheduler: https://github.com/rhuitl/uClinux/blob/master/user/vixie-cro...

In this case, the variable "num3" is the step value.

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ColinWright 2671 days ago

Huh, that's weird. It looks like something got screwed in the copy/paste process, because the previous article I linked definitely has the correct "range/step" format. I thought I had copied it from there, but can't find this example there. And you're absolutely right, the version I quote here is syntactically invalid.

So the syntactically valid version does not work in that earlier cron-to-English translator, but it does appear to work in this version.

My apologies for the error on my part.

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encoderer 2670 days ago

Thanks for following up -- we take correctness of Crontab.guru very seriously!

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