*/2 * * * * date >> ~/time.log
1-59/2 * * * * date >> ~/time.log
30 23 * * * /etc/init.d/apache2 restart
30 23 1-15 * * /etc/init.d/apache2 restart
*/30 23-7 * * * /etc/init.d/apache2 restart
0,30 23-7 * * * /etc/init.d/apache2 restart
0-59/30 23-7 * * * /etc/init.d/apache2 restart
原文:http://www.cnblogs.com/wzzkaifa/p/6900949.html