ubuntu 设置计划任务

非常简便:

crontab -e

以下是我的执行过程，输入命令后，会让我选择一个编辑器，我选的是2，因为后边写着easiest，最简单的。

liuyx@myubuntu:/$ crontab -e
no crontab for liuyx - using an empty one

Select an editor.  To change later, run 'select-editor'.
  1. /bin/ed
  2. /bin/nano        <---- easiest
  3. /usr/bin/vim.tiny

Choose 1-3 [2]: 2
crontab: installing new crontab

选2之后会进入一个文本编辑状态，在里面根据提示，配置你要执行的任务即可：

例如我的配置：

# Edit this file to introduce tasks to be run by cron.
# 
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
# 
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').# 
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
# 
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
# 
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
# 
# For more information see the manual pages of crontab(5) and cron(8)
# 
# m h  dom mon dow   command
* * * * * java -jar /home/liuyx/refreshIp/refreshIp.jar 

只有最后一行是我写的，我的任务的意思是 每分钟执行一下这个jar包。五个*代表时间规则，后边的就是要执行的命令。命令这个不用说，要执行什么就写什么。时间规则是遵循cron表达式，具体请参阅cron表达式的相关写法。

配置完这些之后，记得执行一下：

sudo service cron restart

来让你的配置生效。

完毕。

也可以参阅这个：https://help.ubuntu.com/community/CronHowto