先设置一些基本的参数，开始备份
Router#show flash: 查看IOS系统
System flash directory:
File Length Name/status
3 33591768 c1900-universalk9-mz.SPA.151-4.M4.bin 系统名称 复制下来
2 28282 sigdef-category.xml
1 227537 sigdef-default.xml
[33847587 bytes used, 221896413 available, 255744000 total]
249856K bytes of processor board System flash (Read/Write)
Router#copy flash: tftp: 备份系统
Source filename []? c1900-universalk9-mz.SPA.151-4.M4.bin 备份的名称
Address or name of remote host []? 10.10.10.10 备份到哪个地址
Destination filename [c1900-universalk9-mz.SPA.151-4.M4.bin]? 确定备份回车
Writing c1900-universalk9-mz.SPA 等待配置备份成功
