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 -eno crontab for liuyx - using an empty oneSelect an editor.  To change later, run 'select-editor'.  1. /bin/ed  2. /bin/nano        <---- easiest  3. /usr/bin/vim.tiny Choose 1-3 [2]: 2crontab: 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