The CLI offers a couple of useful shortcuts for us to use:
- You can press the TAB button to auto-complete a command or keyword. This is
VERY useful. If you type “clo” and then press TAB it will auto-complete “clo” to
- CTRL-A brings your cursor to the beginning of the line. This is faster than pressing
the left arrow.
- CTRL-E brings your cursors to the end of the line. This is faster than pressing the
- CTRL-SHIFT-6 interrupts processes like a PING.
- CTRL-C aborts the current command that you were typing and exits configuration
- CTRL-Z ends configuration mode.
Cisco IOS keeps a history of all the commands you previously typed in. You can view them
with the following command:
Above you see an overview of the commands I have used so far. By default, it will only
save the last 10 typed commands but we can increase the history size:
Use the terminal history size command to change it. I‟ve set it to 50 commands.
By pressing the UP or DOWN arrow you can browse through commands you have previously
Show version will display our model, hardware, interfaces and more. We also saw this
output when we just started the switch.
Let‟s take a closer look at the interfaces that this switch has:
The show ip interface brief is a very useful command. It shows us all the interfaces and
their status. This switch has 24x FastEthernet interfaces and 2x Gigabit Interfaces.
The keyword status tells us whether the interface is up or down. This is the physical status
so it means whether there is a cable connected to the interface or not. The keyword
protocol tells us if the interface is operational or not. It‟s possible that the status shows an
interface as up but that the protocol is down because of a security violation.
If we want we can take a closer look at one of the interfaces:
Use the show interface command and specify the interface that you want to look at.
Above you can see an example of the FastEthernet 0/1 interface. Some of the things that
we see are the status, the speed (100Mbit), and the duplex settings (full-duplex). You can
also see the number of incoming and outgoing packets.
So now you have an idea how the CLI works, let‟s continue by creating a basic configuration
for our device.