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Cron Expression to English Translator

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Re: Cron Expression to English Translator

#2

Post by ColinWright »

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/

Re: Cron Expression to English Translator

#3

Post by encoderer »

ColinWright wrote: post #2

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/

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.

Re: Cron Expression to English Translator

#4

Post by ColinWright »

encoderer wrote: post #3
ColinWright wrote: post #2

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/

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…

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.

Re: Cron Expression to English Translator

#5

Post by encoderer »

ColinWright wrote: post #4
encoderer wrote: post #3

Earlier quoted context omitted.

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…

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…

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