進入特權模式
enable
退出特權模式
disable
進入全局模式
configure terminal
進入接口模式
interface fastEthernet 0/1
查看軟硬件信息(寄存器值)
R1#show version
R1#show version
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-J1S3-M), Version 12.3(26), RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2008 by cisco Systems, Inc.
Compiled Mon 17-Mar-08 15:23 by dchih
ROM: ROMMON Emulation Microcode
ROM: C2600 Software (C2600-J1S3-M), Version 12.3(26), RELEASE SOFTWARE (fc2)
R1 uptime is 4 minutes
System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19
System image file is "tftp://255.255.255.255/unknown"
cisco 2621 (MPC860) processor (revision 0x202) with 56320K/9216K bytes of memory.
Processor board ID FTX0945W0MY (4279256517)
M860 processor: part number 0, mask 0
Bridging software.
X.25 software, Version 3.0.0.
TN3270 Emulation software.
2 FastEthernet/IEEE 802.3 interface(s)
128K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash (Read/Write)
Configuration register is 0x2102
IOS解釋：flsah可以放很多的IOS。默認是從第一個IOS啓動，第一個啓動不了啓動第二個。IOS應該有2個,最小的IOS 1M~2M放在ROM裏面，ROM是不可擦也不可寫的。提供最基本的IOS恢復功能。
查看運行的配置文件
Switch#show running-config
解釋：running-config是存在NVRAM裏面的，當IOS啓動的時候把NVRAM裏面的running-config拷貝到RAM裏面去運行，Switch#show running-config是調用RAM裏面的配置文件
查看NVRAM配置文件
Switch#show startup-config
查看所有接口的信息
Switch#show interfaces
查看指定接口的信息
Switch#show interfaces FastEthernet 0/1
FastEthernet0/1 is down, line protocol is down (disabled)
Hardware is Lance, address is 0050.0fac.b501 (bia 0050.0fac.b501)
BW 100000 Kbit, DLY 1000 usec,
解釋：0/1 0代表第幾模塊，1代表模塊裏面的第幾個接口