A famous adage goes:
The pen is mightier than the sword
Perhaps, we could say now that the keyboard has taken that privileged place. Command line tools have a surprising power to give you control over your machine. In the time that it takes to issue a few mouse clicks, trying to do certain routine tasks, many more commands can be supplied using the keyboard.
If you are a power user of GNU/Linux and love the keyboard, or you are a lover of GNU/Linux wanting to become a seasoned user, you'll want more and more to leverage the power of the keyboard by finding and using console based tools. The text based mail client, mutt, empowers you in a big way to make you highly productive and efficient.