A simple test

... to establish whether you're a Mac OS X (or Linux) geek:

View this cartoon. If you fall off your chair laughing, you're an OS X geek.

I laughed, I fell.

That is all.

What, you want an explanation? OK. UNIX-based operating systems like Linux and the Mac OS include a terminal emulation programme which lets you run native UNIX commands; it's raw, ugly, and blisteringly fast, perfect for slicing and dicing humungous amounts of data.

When you use the Terminal programme you have only limited rights: you cannot change other users' data or delete parts of the operating system, which is as it should be. However, there is a way to override this restriction: if you happen to know the administrator's password (usually this is yourself) you can acquire superuser authority, and can make the computer do things that it doesn't want to do. The command to run a process as superuser is sudo.