Chinaunix

标题: crontab问题 [打印本页]

作者: gzhgyzhh 时间: 2012-12-06 15:00
标题: crontab问题
crontab 中，下面有什么区别

我想让我的脚本每小时执行一次命令

* */2 * * * 我这样设置后，每分钟执行一次命令？

0 */2 * * *
* */2 * * *

有知道的请告知下，谢谢

作者: chenyx 时间: 2012-12-06 16:12
* */2 * * *这个是每2小时执行一次,* */1 * * *才是1小时

作者: yizuwei520 时间: 2012-12-06 16:13
鸟哥私房菜里面有讲这个的，你看看。

作者: gzhgyzhh 时间: 2012-12-06 16:35
测试结果

0 */1 * * * 每小时执行一次
* */1 * * * 每分钟执行一次

作者: 枫之歌 时间: 2012-12-06 17:16

gzhgyzhh 发表于 2012-12-06 16:35
测试结果

0 */1 * * * 每小时执行一次

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
# For details see man 4 crontabs
# Example of job definition:
# .---------------- minute (0 - 59)
# | .------------- hour (0 - 23)
# | | .---------- day of month (1 - 31)
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ...
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# | | | | |
# * * * * * user-name command to be executed

复制代码

我也试了一下，事实证明前面的时间一定要填上数值。如果都为*，即使你在月的位置*/1它也是每分钟执行一次。

Commands are executed by cron(

when the
   minute, hour, and month of year fields match the current time, and at least one  of  the  two
   day  fields  (day  of month, or day of week) match the current time (see "Note" below).  Note
   that this means that non-existent times, such as "missing hours" during daylight savings con-
   version,  will  never match, causing jobs scheduled during the "missing times" not to be run.
   Similarly, times that occur more than once (again, during daylight savings  conversion)  will
   cause matching jobs to be run twice.

欢迎光临 Chinaunix (http://bbs.chinaunix.net/)