Re: Where to declare?

[blackmateria]

Move the declaration of @dirlist after the nested sub (getAns), then pass it in as a hard reference:

sub getDirs() {

    sub getAns() {
        my ($dirlist) = @_; # new
        print qq(Enter a valid directory: );
        chomp(my $ans = <STDIN>);
        if ($ans ne "") {
            if ($ans =~ m/foo/g) {
                push(@$dirlist, $ans); # note the @$dirlist
                &getAns;
            } else {
                print qq(That is not a valid directory!\n);
                &getAns;
                }
            } else {
                return @$dirlist; # note the @$dirlist
            }
        }

    my @dirlist;
    my @dirs = getAns(\@dirlist); # note the \@dirlist
    
    if (@dirs) {
        return @dirs;
    } else {
        die qq(No directories have been entered!\n);
    }

}

For more information on hard references, take a look at perlref.

Just a stylistic note, you don't need to put the & on getAns to call if if you're already using () (the original has a line which read my @dirs = &getAns()). As a matter of fact, you should stay away from using & to call subroutines unless you understand how it's different from calling them with (). Calling with & makes @_ in the called subroutine an alias for @_ in the caller; () makes a copy instead. So changing the parameters in the subroutine could affect the variables used in the main program. This is probably not what you expect! Be careful. If I were you, I'd change the places in your code that call &getAns to getAns().

Anyway, hope this helps.