Place a string in the middle of the screen - in bash

For ages my shell is greeting me with "Let's boogie, Mr Swine". I had it printed in fixed offset but following a discussion in comp.lang.python I decided to get the screen size and calculate the exact location.

I'm using tput to get the size and the fact that printf can get the width of the string as a parameter if you specify a * there (BTW - Python supports that as well)

Here's the code.