Receive/Transmit

I have a very short but very useful command for you today. You’ll often find yourself working within the IOS config mode, and you might forget little things such as ‘what is the interface number I need’, or ‘what is the current IP assigned to this interface’. Following this you probably go through a series of commands like the ones below

Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#int fa 0/^Z  <---Arrgh forgot which interface it was, Ctrl+Z out of config mode
% Incomplete command.

Router#sh ip int brief
Interface                  IP-Address      OK? Method Status                Prot
ocol
FastEthernet0/0            10.10.10.1  YES NVRAM  up                    up

FastEthernet0/1            192.168.0.1   YES NVRAM  up                    up

Router#conf t  <---OK found it, back into config mode
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#int fa 0/0
etc

This gets annoying pretty fast, but luckily you can execute exec commands from within config mode by preceding them with ‘do’! This is a lot nicer:

Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#int fa 0/  <---Arrgh forgot which interface it was, lets try 'do'
% Incomplete command.

Router(config)#do sh ip int brief
Interface                  IP-Address      OK? Method Status                Prot
ocol
FastEthernet0/0            10.10.10.1  YES NVRAM  up                    up

FastEthernet0/1            192.168.0.1   YES NVRAM  up                    up

Router(config)#int fa 0/0

Much easier right? There are of course a few caveats, the main one being that you can’t use the ‘?’ symbol to remind you of the commands but its still a great little time saver.