Crontab格式化-每15分钟 [英] Crontab Formatting - every 15 minutes

问题描述

我试图让每15分钟运行一次简单的crontab作业，并且在决定如何设置时间格式时遇到麻烦。

I'm trying to get a simple crontab job to run every 15 minutes and am having trouble deciding how to format the timing.

我一直在介绍的内容向下是以下内容：

What I've been putting down is the following:

15 * * * * ------------------------

我很确定这只是运行的前15分钟

I'm pretty sure this just runs the first 15 minutes of every hour.

我认为crontab允许用户指定确切的运行时间，即：

I think that crontab allows users to specify exact times to run, namely:

0, 15,30,45 * * * * -------------------------

但是，如果我想从启动那一刻起每隔15分钟运行一次crontab，（不一定是可整除的值）到15点），我该如何格式化/有可能吗？

But if I wanted to run the crontab every 15 minutes from the moment I start it, (which may not necessarily be on a value divisible by 15), how would I go about formatting that/is that possible?

推荐答案

Crontab不记得您什么时候开始（大概是您执行 crontab -e 或 crontab文件名命令的时间）。

Crontab doesn't remember what time you "started" (presumably the time you executed the crontab -e or crontab filename command).

如果要每15分钟运行一次作业从任意时间开始，您必须指定该时间。

If you want to run the job every 15 minutes starting from an arbitrary time, you'll have to specify that time. This:

7-59/15 * * * * command

将在每小时之后的7、22、37和52分钟运行。假设您正在运行Vixie cron，这是最常见的实现。为了获得更好的可移植性，您可以使用：

will run at 7, 22, 37, and 52 minutes after each hour. That's assuming you're running Vixie cron, which is the most common implementation. For better portability, you can use:

7,22,37,52 * * * * command

请记住，前5个字段中都不能有空格；如您所问的那样， 0、15、30、45 无效。

And remember that you can't have spaces within any of the first 5 fields; 0, 15,30,45, as you had in your question, is invalid.

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