A short listing of handy commands used on a regular basis:
#show ip interface brief
Shows status of the interfaces on the device, including up/down and ip information.
#show ip protocol summary
Will show you all the routing protocols running on the router
Will display the configured log settings and buffered log messages
#show interfaces status
Shows Port, Status, VLAN, Duplex, Speed and Type for all interfaces.
#show interfaces summary
Live traffic stats on the interfaces.
#show ip arp
Displays the IP to MAC Address resolution for all the IP’s on the device, and from the interfaces it was learned.
#show mac address-table
Shows the MAC table entry and interface it is being seen on.
#show policy-map [interface]
Displays the QoS Policy information
#show interfaces link
Will display how long the interface has been disconnected
Displays information about the device. It gives you details such as; IOS version, System Uptime, Image filename, Type of Processor, Amount of RAM, Number of Ports, Flash Memory, MAC Address and Serial Number
Displays the clock status
#show version | include uptime
Shows the uptime of the device
#show processes cpu
Displays the CPU utilisation stats
#show processes cpu history
Displays a one minute output, and so on……
Lists the commands the user has entered in the session
Displays all the inventory information about the device
Lines connected on the router’s physical ports, such as serial connected.
#show cdp neighbour
Shows the directly connected devices with local and remote interfaces, via Cisco’s Discovery Protocol