crontab的第五场 [英] Fifth field of crontab
问题描述
我是LINUX的新手.我对cron的工作方式有一个清晰的认识,但是突然间,我心中产生了一个小疑问.假设我想在3月5日凌晨5.30执行 ls
命令,那么我的 cron
命令将是 30 05 05 03 ??
ls.
I am new to LINUX. I have a clear idea on how cron works, but suddenly a small doubt struck at my mind. Suppose if I want to execute ls
command on 5th march 5.30AM, then my cron
command will be 30 05 05 03 ??
ls.
我的简单问题是,什么条目将出现在 ??
位置.并假设如果我在该位置输入 01
而不是 ??
,将会发生什么情况.如果这是一个简单的问题,请原谅,请帮助我解决同样的问题.
My simple question is that what entry will come on ??
place. And suppose if I enter 01
in that position instead of ??
, what will happen. Please excuse me if this is a simple question and please help me solve the same.
推荐答案
在您的情况下
30 05 05 03 * command to be executed
- - - - -
| | | | |
| | | | +----- day of week (0 - 6) (Sunday=0)
| | | +------- month (1 - 12)
| | +--------- day of month (1 - 31)
| +----------- hour (0 - 23)
+------------- min (0 - 59)
??
说,您不在乎星期几,因为您已经在说出确切的日期.如果放置 01
,它仍然可以运行,但有多余.
??
says that you don't mind the day of the week because you are already stating the exact date. If you place the 01
it would still run but its redundant.
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