What argv0 said.
$& is for improving code readability. If code lines are too long, you may be forced to scroll horizontally, which is undesirable. What I showed here was just demo code, but originally the loop condition line was very long. (I probably should've written it more elegantly, but that's a different story.
)
Actually, I'm seriously surprised no one's ever bumped into such a general use case (myself included).
