use strict;
use warnings;

while(<DATA>)
{
    chomp;
    my $old = $_;
    s/\.(?=.*?\.)/_/g;
    print "Change: $old to $_\n";
}


__END__
test0.file0.new_20060411.zip
test1.file1.new_20060411.zip
test2.file2.new_20060411.zip
test3.file3.new_20060411.zip