Shell Programming and Scripting

a x 1 5
b x 3 10
b x 4 9
b x 5 16
c x 5 9
c x 4 8

a x 1 5
b x 3 16
c x 4 9

awk '{idx=$1 FS $2}FNR==1{a3[idx]=$3}{a3[idx]=(a3[idx]>$3)?a3[idx]:$3;a4[idx]=($4>a4[idx])?$4:a4[idx]} END{for(i in a3)print i,a3[i],a4[i]}' myFile

awk '
        {
                F[$1 FS $2] = F[$1 FS $2] ? F[$1 FS $2] : $3
                F[$1 FS $2] = F[$1 FS $2] > $3 ? $3 : F[$1 FS $2]
                S[$1 FS $2] = S[$1 FS $2] < $4 ? $4 : S[$1 FS $2]
        }
        END {
                for ( k in F )
                        print k, F[k], S[k]
        }
' file