If you want to affect the elements 1..10, you could set $[ to 1 and iterate from 0 to less than ten, as your code describes. That seems like a contrived example to me. What problem are you trying to solve?

I fiddled with $/ for the first time yesterday in order to read in a file in one big slurp, but I generally leave the 'system dollar' variables alone.

In any case, I believe $[ is going away in Perl 6 -- so it's probably best not to get into the habit of using it anyway.