open ONE, $FILE1; while () { chomp; if ($_=~/^(.*)\t(.*)/) { $hash1{$1} =$2; } } foreach $key(keys %hash1) { open TWO, $FILE2; while () { chomp; if ($_=~/^$key\t(.*)/) { if ($1 eq $hash1{$key}) { print $key."\t".'OK'."$hash1{$key}"."\n"; } else { print $key."\t".'WRONG'."\t".$hash1{$key}."\n"; } } } }