非常簡便:
crontab -e
以下是我的執行過程，輸入命令後，會讓我選擇一個編輯器，我選的是2，因為後邊寫著easiest，最簡單的。
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
選2之後會進入一個文字編輯狀態，在裡面根據提示，配置你要執行的任務即可：
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
只有最後一行是我寫的，我的任務的意思是 每分鐘執行一下這個jar包。五個*代表時間規則，後邊的就是要執行的命令。命令這個不用說，要執行什麼就寫什麼。時間規則是遵循cron表示式，具體請參閱cron表示式的相關寫法。
配置完這些之後，記得執行一下：
sudo service cron restart
來讓你的配置生效。
完畢。
也可以參閱這個：https://help.ubuntu.com/community/CronHowto