功能：查看设备的版本信息：包括设备类型、IOS版本、FLASH内存大小、NVRAM内存大小、拥有的接口信息、配置寄存器的值等
实例：
chj#show version
Cisco Internetwork Operating System Software
IOS (tm) 7200 Software (C7200-IS-M), Version 12.2(37), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2006 by cisco Systems, Inc.
Compiled Thu 15-Jun-06 19:51 by pwade
Image text-base: 0x60008940, data-base: 0x61316000
ROM: ROMMON Emulation Microcode
BOOTLDR: 7200 Software (C7200-IS-M), Version 12.2(37), RELEASE SOFTWARE (fc1)
#硬件平台是：7200-IS-M，IOS版本号是12.2，发布号37
chj uptime is 5 minutes
System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19
cisco 7206VXR (NPE400) processor (revision A) with 57344K/8192K bytes of memory.
#拥有56M的系统内存和8M的共享数据包内存
Processor board ID 4294967295
R7000 CPU at 150Mhz, Implementation 39, Rev 2.1, 256KB L2, 512KB L3 Cache #CPU信息
6 slot VXR midplane, Version 2.1
Last reset from power-on
Bridging software.
X.25 software, Version 3.0.0.
1 FastEthernet/IEEE 802.3 interface(s) #拥有一个快速以太网口
4 Serial network interface(s) #拥有4个串口
125K bytes of non-volatile configuration memory. #NVRAM的大小为125K
65536K bytes of ATA PCMCIA card at slot 0 (Sector size 512 bytes). #ATA PCMCIA大小为64M
8192K bytes of Flash internal SIMM (Sector size 256K). #8M的FLASH内存
Configuration register is 0x2102 #配置寄存器的值，0X2102 是从NVRAM 中启动router，如果是0X2142 是忽略NVRAM中的配置，从SETUP启动
存手工创作:)
