Shell Programming and Scripting

awk '{       A[ $1 "#" $2 ]++;       }
END {   for(K in A)
        {
                split(K, L, "#");
                STR=L[1]        ;       VAL=L[2]

                if(C[STR] <= A[K])      C[STR]=A[K];
        }

        for(K in C)     print K, C[K];
}' < data

 
$ awk '{print $1}' inputfile | sort -u | while read word; do sort inputfile| uniq -c | sort -r -n -k1 -k2 | grep $word | head -1; done
   1 ABC   4
   4 DEF   2
   3 XYZ   4