$ /etc/init.d/apache2 restart * Restarting web server apache2 [fail]
解决办法4步走:
1. sudo /etc/init.d/apache2 stop
2. sudo killall apache2
3. sudo netstat -l|grep www # 确认没有服务占用80端口
4. sudo /etc/init.d/apache2 restart
[ubuntu] service apache2 restart [fail]
原文：http://www.cnblogs.com/bushe/p/4382911.html