It's a fake terminal but it's surprisingly fully functional (lots of commands work, tab autocompletion, etc.)
That is, within the shell you can't switch through your browser tabs via Ctrl+Tab or Ctrl+Shift+Tab.
(Maybe this is the fault of Firefox. Why should it grant any web application the right to redefine essential browser navigation keystrokes?)
And perhaps also a section on ancient, but widely used, systems like autotools — even something as simple as ./configure --prefix would be useful to have known...
Hmz, I wonder if the author is aware of this thread on HN?
I think that maybe programming and Make examples were unnecessary -- they don't really give any idea about what to do with the language and don't present any paradigms or quirks that you might need and there are much better short tutorials on that topic out there. All in all, this wouldn't save you if you got to write something in C++, but this would definitely help if you need to remember some unix command that's just slipped your mind.
Though they might have included stuff for LVM to 'file system' section, LVM commands are more or less intuitive as they are.