保存现有的配置，可以用
copy running-config startup-config 
copy system:running-config nvram:startup-config
还可以使用write memory 可以简写成wr  这个命令是在老式的IOS中的，不过新的IOS也是支持的
 
Router#copy running-config startup-config   //1
Destination filename [startup-config]?
Building configuration...
[OK]
Router#copy system:running-config startup-config   //2
Destination filename [startup-config]?
Building configuration...
[OK]
Router#copy syste
Router#copy system:running-config nvram:startup-config  //同2
Destination filename [startup-config]?
Building configuration...
[OK]
Router#write memory //3
Building configuration...
[OK]
Router#wr     //同3
Building configuration...
[OK]
Router#