my $dir = 'input_files';
die "can't opendir $!" unless opendir DIR, $dir;
while (defined(my $file = readdir DIR)) {
    do {
        print "The directory and file are $dir/$file\n";
        die "Can't open input file $!" unless open IN, "< $dir/$file";
        use File::Glob ();
        while (defined($_ = glob(' IN '))) {
            print $_;
        }
    };
}
closedir DIR;