You're most welcome! Am glad it helped.

You're commenting is correct. You asked, "why use $_ here?" Because Perls default scalar ($_) is implicitly used in the for loop that's iterating through the elements of @ARGV. Note, also, that Perl's default scalar is also implicitly used in the expression if (-e) { as that expression is equivalent to if (-e $_) {.

The purpose of next is to get the next element of @ARGV, otherwise a warn would occur.