sub createDir {
    my $dirName = shift;
    if (-e $dirName) {
        if (-d $dirName) {
            return "Directory $dirName already exists!";
        }
        else {
            return "Can't create $dirName because there's a file in the way!";
        }
    }
    mkdir $dirName or return $!;
}

##</code><code>##

mkdir $path or die "Can't mkdir $path: $!";