记一次由于时间导致的crontab任务执行时间错误

zmx

2023 年 04 月 25 日

255 次浏览

暂无评论

2820字数

linux

# 概念

## RTC Time

RTC（Real Time Clock，实时时钟）也叫做 CMOS 时钟，它是 PC 主机板上的一块芯片（或者叫做时钟电路），它靠电池供电，即使系统断电也可以维持日期和时间。

# 操作

```bash
┌[root@localhost] [/dev/pts/0] 
└[~]> timedatectl
               Local time: Tue 2023-04-25 16:48:08 CST
           Universal time: Tue 2023-04-25 08:48:08 UTC
                 RTC time: Tue 2023-04-25 08:48:08
                Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no
```

时区和时间的准确性

## 修改时间

```bash
date -s  "2023-04-25 16:00:00"
```

## 修改时区

```bash
┌[root@localhost] [/dev/pts/0] 
└[~]> tzselect 
Please identify a location so that time zone rules can be set correctly.
Please select a continent, ocean, "coord", or "TZ".
 1) Africa
 2) Americas
 3) Antarctica
 4) Asia
 5) Atlantic Ocean
 6) Australia
 7) Europe
 8) Indian Ocean
 9) Pacific Ocean
10) coord - I want to use geographical coordinates.
11) TZ - I want to specify the time zone using the Posix TZ format.
#? 4
Please select a country whose clocks agree with yours.
 1) Afghanistan			 29) Kyrgyzstan
 2) Antarctica			 30) Laos
 3) Armenia			 31) Lebanon
 4) Azerbaijan			 32) Macau
 5) Bahrain			 33) Malaysia
 6) Bangladesh			 34) Mongolia
 7) Bhutan			 35) Myanmar (Burma)
 8) Brunei			 36) Nepal
 9) Cambodia			 37) Oman
10) China			 38) Pakistan
11) Christmas Island		 39) Palestine
12) Cocos (Keeling) Islands	 40) Philippines
13) Cyprus			 41) Qatar
14) East Timor			 42) Russia
15) French Southern Territories	 43) Réunion
16) Georgia			 44) Saudi Arabia
17) Hong Kong			 45) Seychelles
18) India			 46) Singapore
19) Indonesia			 47) Sri Lanka
20) Iran			 48) Syria
21) Iraq			 49) Taiwan
22) Israel			 50) Tajikistan
23) Japan			 51) Thailand
24) Jordan			 52) Turkmenistan
25) Kazakhstan			 53) United Arab Emirates
26) Korea (North)		 54) Uzbekistan
27) Korea (South)		 55) Vietnam
28) Kuwait			 56) Yemen
#? 10
Please select one of the following time zone regions.
1) Beijing Time
2) Xinjiang Time, Vostok
#? 1

The following information has been given:

China
	Beijing Time

Therefore TZ='Asia/Shanghai' will be used.
Selected time is now:	Tue Apr 25 16:41:39 CST 2023.
Universal Time is now:	Tue Apr 25 08:41:39 UTC 2023.
Is the above information OK?
1) Yes
2) No
#? 1

You can make this change permanent for yourself by appending the line
	TZ='Asia/Shanghai'; export TZ
to the file '.profile' in your home directory; then log out and log in again.

Here is that TZ value again, this time on standard output so that you
can use the /usr/bin/tzselect command in shell scripts:
Asia/Shanghai
```

## 重启corn

```bash
systemctl restart crond
```

## 写个测试脚本

```crontab
57 16 * * * touch /tmp/111
```

看看文件是否创建成功