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| zh:docs:guide-user:base-system:cron [2019/11/03 13:27] – [Extras] longgenxing | zh:docs:guide-user:base-system:cron [2019/11/04 01:03] – [定期重启] longgenxing | ||
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| - | FIXME **This page is not fully translated, yet. Please help completing the translation.**\\ //(remove this paragraph once the translation is finished)// | ||
| - | |||
| ====== Cron and crontab ====== | ====== Cron and crontab ====== | ||
| ====== Cron软件 及其 crontab命令使用 ====== | ====== Cron软件 及其 crontab命令使用 ====== | ||
| Line 110: | Line 108: | ||
| ===== 其他 ===== | ===== 其他 ===== | ||
| ==== Periodic reboot ==== | ==== Periodic reboot ==== | ||
| + | ==== 定期重启 ==== | ||
| A simple solution for some hard-to-solve problems (memory leak, performance degradation, | A simple solution for some hard-to-solve problems (memory leak, performance degradation, | ||
| + | |||
| + | **中文翻译**:用来对付一些系统运行时出现的难题(比如内存泄露、性能下降、......)的法宝就是每晚定期重启。 | ||
| However, this is not as simple as it seems, because the router usually does not have a real-time clock. | However, this is not as simple as it seems, because the router usually does not have a real-time clock. | ||
| This could lead to a never-ending loop of reboots. | This could lead to a never-ending loop of reboots. | ||
| + | |||
| + | **中文翻译**:即便是这样重启,也不是那么简单就能做到的,因为这样的路由器通常没有实时时钟。弄不好就成为下面这个怪圈: | ||
| In the boot process the clock is initially set by '' | In the boot process the clock is initially set by '' | ||
| Line 120: | Line 123: | ||
| Then cron starts and notices a few seconds later that the required boot moment has again arrived and reboots again... | Then cron starts and notices a few seconds later that the required boot moment has again arrived and reboots again... | ||
| (At the end of the boot process ntpd starts, and it may also take a while before ntpd gets and sets the correct time, so cron may start the reboot in between.) | (At the end of the boot process ntpd starts, and it may also take a while before ntpd gets and sets the correct time, so cron may start the reboot in between.) | ||
| + | |||
| + | **中文翻译**:在启动的时候,当前系统的时间使用“sysfixtime”程序来设置;设定依据是在/ | ||
| + | 它可能是一个状态文件,或者配置文件,它可能在cron定时任务需要重启系统前30秒刚做了修改。 | ||
| + | 所以,如果在重启系统的过程中,系统时间被设置为这个文件的时间属性的前若干秒钟的话。 | ||
| + | 当cron软件开始计时,cron马上又会发现,设置的重启的时间又到了,然后又开始重启了…… | ||
| + | (还有的可能就是:启动流程的最后ntpd的时间服务启动了,这个软件得需要一阵子才能获取并且设置正确的时间,所以这段时间内,cron定时重启任务又被触发重启了。) | ||
| One solution for cron is to use a delay and touch a file in ''/ | One solution for cron is to use a delay and touch a file in ''/ | ||
| + | |||
| + | **中文翻译**:一种解决cron定时重启任务的怪圈的办法是在重启前,推迟一会儿重启,同时主动用touch命令去修改/ | ||
| <code bash> | <code bash> | ||
| Line 128: | Line 139: | ||
| # and touch a file in /etc so clock will be set | # and touch a file in /etc so clock will be set | ||
| # properly to 4:31 on reboot before cron starts. | # properly to 4:31 on reboot before cron starts. | ||
| + | 30 4 * * * sleep 70 && touch /etc/banner && reboot | ||
| + | </ | ||
| + | |||
| + | **中文翻译**:举例crontab的配置如下: | ||
| + | <code bash> | ||
| + | # 每天上午4: | ||
| + | # 注意: 为了防止循环重启的怪圈,需要推迟70秒钟执行重启 | ||
| + | # 在/ | ||
| + | # 为上午4: | ||
| 30 4 * * * sleep 70 && touch /etc/banner && reboot | 30 4 * * * sleep 70 && touch /etc/banner && reboot | ||
| </ | </ | ||
| Line 134: | Line 154: | ||
| There is usually no programmable circuitry to actually power off the unit. | There is usually no programmable circuitry to actually power off the unit. | ||
| '' | '' | ||
| + | |||
| + | **中文翻译**:: | ||
| + | 这通常是因为这样的设备没有去执行断电的电路。 | ||
| However, a more flexible approach is to use use the [[packages: | However, a more flexible approach is to use use the [[packages: | ||
| + | |||
| + | **中文翻译**:即便这样,也还是可以使用一种更为灵活的方法,通过使用[[packages: | ||
| + | 安装命令如下: | ||
| <code bash> | <code bash> | ||
| Line 143: | Line 169: | ||
| ==== Alarm clock ==== | ==== Alarm clock ==== | ||
| + | ==== 闹钟功能 ==== | ||
| If you have [[wp> | If you have [[wp> | ||
| When DST starts in central Europe, clocks advance from 02:00 CET to 03:00 CEST on last Sunday in March. | When DST starts in central Europe, clocks advance from 02:00 CET to 03:00 CEST on last Sunday in March. | ||
| Line 148: | Line 175: | ||
| Later won't work, you'll be late ;-) | Later won't work, you'll be late ;-) | ||
| When DST ends in central Europe, clocks retreat from 03:00 CEST to 02:00 CET on last Sunday in October. | When DST ends in central Europe, clocks retreat from 03:00 CEST to 02:00 CET on last Sunday in October. | ||
| + | |||
| + | **中文翻译**:如果你所在的地区使用“夏令时”[[wp> | ||
| + | 假设你在欧洲中部使用“夏令时”,那么时钟在每年3月份,就要提前从中欧时间的2点,变成了3点的中欧夏令时时间。 | ||
| + | 在此之前的6天,你可以把自己的网络唤醒闹钟每天提前10分钟。 | ||
| + | 如果没生效的话,估计你上班就要迟到了;) | ||
| <code bash> | <code bash> | ||
| Line 155: | Line 187: | ||
| </ | </ | ||
| + | **中文翻译**: | ||
| + | |||
| + | <code bash> | ||
| + | #分 时 日 月 星 执行命令 | ||
| + | 59 05 * * 1 / | ||
| + | # | ||
| + | </ | ||
| + | |||
| + | |||
| + | ==== 翻译信息 ==== | ||
| + | LongGenxing 20191103 第一次翻译 | ||