On Sat, Apr 11, 2015 at 05:11:41PM -0800, I wrote:
-bash: sudo: command not found
Looks like you might want to "apt-get install sudo".
That said, if you're running the command as root already, you can just omit the 'sudo' word.
Once you have done the apt-get sudo, do a 'man sudo' and you can read about what it is. It is one of the simple and pervasive unix commands that all sysadmins tend to know about -- but it is a tiny bit tricky here because Ubuntu basically forces you to know about it in order to do anything, whereas Debian doesn't.
Hope that helps, --Roger