Permission denied using dd to clone main drive

So I'm trying to clone the setup of one computer to 4 identical machines on the same network. I don't fancy the idea of meddling with the insides of the computer, so I'm following the method outlined here

However, whenever I try the method outlined in the accepted answer, I get
dd: opening 'dev/sda1':Permission denied

Since the drive I'm cloning is my main partition, I'm running both machines off of live CDs. I thought it might not be working because I can't clone the drive when it's mounted, but running umount /dev/sda1 / says it's not mounted.

I'm not 100% set on using this particular method, if there's some other way that would also get the job done.

Solution 1:

Try this: press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command(s) below:

sudo -i 

That will give you a root shell, that way it'll all run as root.

Solution 2:

I've always used Clonezilla when cloning drives for identical computers. It runs off a liveCD and is really easy to use. With this method you can create an img file of the base system. So in a few months if a system crashes you have that fresh image ready to go.