在ubuntu14.04 上面启动apache2，出现下面的错误：

There are processes named 'apache2' running which do not match your pid file which are left untouched in the name of safety, Please review the situation by hand. 

解决办法：

pidof apache2
sudo kill -9 pid
sudo service apache2 restart

或者

sudo kill -9 $(pidof process_name) 
sudo service apache2 restart