To answer your last question about. The use of "our" keeps the variable in scope and does not restrict $color to the current lexical scope. Basically, when used outside of any brace delimited block, it lasts through the end of the compilation unit ( Learning Perl p133) which, in your case, should be the entire program. Consequently, when you are inside the loop, $color refers to the variable you expect it to and not the locally scoped variable that occurs with "my". "our" also allows the subroutine print_color() to access the variable which the "my" declaration would not since lexical variables are hidden from any subroutine called from their scope.