如何添加在所有我的cron作业之前运行的预挂机和挂机后脚本？ [英] How do I add pre-hook and post-hook scripts that run before all of my cron jobs?

问题描述

假设我有以下cron条目：

Suppose I have the following cron entry:

* * * * * /bin/date

现在假设我想要在cron作业运行之前和之后运行的脚本。

Now suppose that I want scripts that run both before and after the cron job runs.

我可以修改cron条目如下：

I could modify the cron entry to look like this:

* * * * * /bin/prehook ; /bin/date ; /bin/posthook

或者如果我想要prehook的退出代码来确定日期命令运行，我可以这样做：

Or if I wanted the exit code of the prehook to determine whether or not the date command runs, I could do this:

* * * * * /bin/prehook && /bin/date ; /bin/posthook

但是，我在寻找一个解决方案，到所有cron作业，而不需要编辑每个crontab;我认为这类似于许多版本控制系统中看到的预提交和后提交的钩子。

However, I'm looking for a solution that I might be able to apply globally to all cron jobs without editing every single crontab; I see this as analogous to pre-commit and post-commit hooks that you see in many version control systems.

推荐答案

我使用的是 crontab 条目总是由一个脚本名称组成，如：

The system I use is that a crontab entry always consists of a single script name, such as:

3  1  *  *  *  /home/me/bin/Cron/daily

/ home / me / bin / Cron / daily 中的脚本实际上是指向单个脚本 runcron 的链接看看它是什么（例如 daily ）。它设置了我的环境（因为 cron 不会设置超过非常最小的环境），然后运行 / home / me / bin / daily 。如果（当）我需要调试cron或添加预钩子或后挂钩，我可以做到全局（通过修改 / home / me / bin / Cron / runcron ）或本地（通过将 runcron 临时修改为 / home / me / bin / Cron / daily c> script）。这种灵活性在我需要它的那些场合非常有用，并且不涉及实际 crontab 条目的任何变化。

The script in /home/me/bin/Cron/daily is actually a link to a single script, runcron, which looks at what it is called (e.g. daily). It sets my environment (since cron does not set more than the very barest of minimal environments), and then runs /home/me/bin/daily. If (when) I need to debug cron, or add pre-hooks or post-hooks, I can do it globally (by modifying /home/me/bin/Cron/runcron) or locally (by making /home/me/bin/Cron/daily temporarily into a modified copy of the normal runcron script). This flexibility is very useful on those occasions when I need it, and doesn't involve any change in the actual crontab entry.

如果提供了参数，我的脚本会传递参数。我从来没有找到足够的理由使用该功能，但长期。我有每日，工作日，每周 code> monthly 。 （另请参见我在哪里可以设置crontab的环境变量使用？）

My scripts do relay arguments if they're provided. I've never found sufficient reason to use that functionality in the long term, though. I have entries for daily, weekday, weekly and monthly. (See also Where can I set environment variables that crontab will use?)

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