#!/bin/ksh
printf "Following assumes all entries with matching field 1 & field 2 are
adjacent and prints the last entry found.\n"
awk 'BEGIN {FS = OFS = ";"}
last != $1 FS $2 {
        if(last != "") print last, hi3
        last = $1 FS $2
        hi3 = $3
        next
}
        {hi3 = $3}
END {   if(last != "") print last, hi3}' input

printf "\nFollowing assumes all entries with matching field 1 & field 2 are
adjacent and prints the entry with highest value in field 3.\n"
awk 'BEGIN {FS = OFS = ";"}
last != $1 FS $2 {
        if(last != "") print last, hi3
        last = $1 FS $2
        hi3 = $3
        next
}
        {if($3 > hi3) hi3 = $3}
END {   if(last != "") print last, hi3}' input

printf "\nFollowing assumes entries with matching field 1 & field 2 might not be
adjacent and prints the last entry found.  Output order is not guaranteed to
match the order of first appearance in the input file.\n"
awk 'BEGIN {FS = OFS = ";"}
{       k3[$1 FS $2] = $3}
END {   for (k in k3) print k, k3[k]}' input

printf "\nFollowing assumes entries with matching field 1 & field 2 might not be
adjacent and prints the highest entry found.  Output order is not guaranteed to
match the order of first appearance in the input file.\n"
awk 'BEGIN {FS = OFS = ";"}
{       if(kc[$1 FS $2]++ == 0) k3[$1 FS $2] = $3
        else if($3 > k3[$1 FS $2]) k3[$1 FS $2] = $3
}
END {   for (k in kc) print k, k3[k]}' input

printf "\nFollowing assumes entries with matching field 1 & field 2 might not be
adjacent and prints the highest entry found.  Output order is guaranteed to
match the order of first appearance in the input file.\n"
awk 'BEGIN {FS = OFS = ";"}
{       if(kc[$1 FS $2]++ == 0) {
                k3[$1 FS $2] = $3
                order[++cnt] = $1 FS $2
        } else if($3 > k3[$1 FS $2]) k3[$1 FS $2] = $3
}
END {   for(i = 1; i <= cnt; i++) print order[i], k3[order[i]]}' input

split;test;2
ref.1;rack.1;2
ref.1;rack.1;1
ref.1;rack.2;1
split;test;3
ref.2;rack.3;1
ref.2;rack.3;2
ref.2;rack.3;3
split;test;1

Following assumes all entries with matching field 1 & field 2 are
adjacent and prints the last entry found.
split;test;2
ref.1;rack.1;1
ref.1;rack.2;1
split;test;3
ref.2;rack.3;3
split;test;1

Following assumes all entries with matching field 1 & field 2 are
adjacent and prints the entry with highest value in field 3.
split;test;2
ref.1;rack.1;2
ref.1;rack.2;1
split;test;3
ref.2;rack.3;3
split;test;1

Following assumes entries with matching field 1 & field 2 might not be
adjacent and prints the last entry found.  Output order is not guaranteed to
match the order of first appearance in the input file.
split;test;1
ref.2;rack.3;3
ref.1;rack.1;1
ref.1;rack.2;1

Following assumes entries with matching field 1 & field 2 might not be
adjacent and prints the highest entry found.  Output order is not guaranteed to
match the order of first appearance in the input file.
split;test;3
ref.2;rack.3;3
ref.1;rack.1;2
ref.1;rack.2;1

Following assumes entries with matching field 1 & field 2 might not be
adjacent and prints the highest entry found.  Output order is guaranteed to
match the order of first appearance in the input file.
split;test;3
ref.1;rack.1;2
ref.1;rack.2;1
ref.2;rack.3;3