edstromp points out this New York Times "story on using a pocket pc to translate a street sign. It requires at least a dialup connection as it sends the photo to a server for the majority of the processing: OCR, translation, English overlay for new image, and then transmission back to the user. All said and done, it takes about 15 seconds to translate a street sign. Put this with some augumented reality, and you have a rather useful tool."
egrep patterns are full regular expressions; it uses a fast deterministic
algorithm that sometimes needs exponential space.
-- unix manuals