47 lines
1.3 KiB
Markdown
47 lines
1.3 KiB
Markdown
---
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weight: 10
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---
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# Cron schedule syntax
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The Vieter cron daemon uses a subset of the cron expression syntax to schedule
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builds.
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## Format
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`a b c d`
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* `a`: minutes
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* `b`: hours
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* `c`: days
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* `d`: months
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An expression consists of two to four sections. If less than four sections are
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provided, the parser will append `*` until there are four sections. This means
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that `0 3` is the same as `0 3 * *`.
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Each section consists of one or more parts, separated by a comma. Each of these
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parts, in turn, can be one of the following (any letters are integers):
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* `*`: allow all possible values.
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* `a`: only this value is allowed.
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* `*/n`: allow every n-th value.
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* `a/n`: allow every n-th value, starting at a in the list.
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* `a-b`: allow every value between a and b, bounds included.
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* `a-b/n`: allow every n-th value inside the list of values between a and b,
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bounds included.
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Each section can consist of as many of these parts as necessary.
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## Examples
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* `0 3`: every day at 03:00AM.
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* `0 0 */7`: every 7th day of the month, at midnight.
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## CLI tool
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The Vieter binary contains a command that shows you the next matching times for
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a given expression. This can be useful for understanding the syntax. For more
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information, see
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[vieter-schedule(1)](https://rustybever.be/man/vieter/vieter-schedule.1.html).
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