在安装nagios4.0.2时报错：
Error: Could not open command file ‘/usr/local/nagios/var/rw/nagios.cmd’ for update!

这明显是权限问题，因此我们只需修改权限并重新启动nagios服务。

执行以下步骤：

chmod 666 /usr/local/nagios/var/rw/nagios.cmd
chown nagios.nagcmd /usr/local/nagios/var/rw 
chmod u+rwx /usr/local/nagios/var/rw
chmod g+rwx /usr/local/nagios/var/rw  
chmod g+s /usr/local/nagios/var/rw

重启nagios

/etc/init.d/nagios restart