UNIX for Dummies Questions & Answers

A A 5
A B 6
A C 1
A D 7
B A 8

A A 5
A B 14
A C 1
A D 7

#!/bin/bash
awk '{print $1}' $1 > 1.txt
awk '{print $2}' $1 > 2.txt
awk '{print $3}' $1 > 3.txt
paste 1.txt 2.txt | tr '\t' '_' > non-reverse.txt
paste 2.txt 1.txt | tr '\t' '_'> reverse.txt
paste non-reverse.txt 3.txt > tt; mv tt non-reverse.txt
paste reverse.txt 3.txt > tt; mv tt reverse.txt
cat reverse.txt non-reverse.txt > duplicates.txt
cat duplicates.txt | sort -nk1 | uniq > tt; mv tt duplicates.txt
awk '{print $1}' duplicates.txt | sort -nk1 | uniq > pair
for i in `cat pair`; do echo $i >> tt ; grep $i duplicates.txt | awk '{ sum+=$2} END {print sum}' >> tt; done
mv tt added_duplicates.txt
sed '$!N;s/\n/,/' added_duplicates.txt  | sort -nk1 | uniq > tt; mv tt final.txt
cat final.txt | tr '_' ' ' | tr ',' ' ' | grep ^[A-Z]  > tt; mv tt final.txt
rm -rf added_duplicates.txt non-reverse.txt reverse.txt duplicates.txt pair added_duplicates

awk '{i=($2<$1?$2" "$1:$1" "$2);A[i]+=$NF}END{for(k in A) print k,A[k]}' yourfile

awk '
        {
                i = $2 FS $1
                if ( i in A )
                {
                        A[i] += $3
                        next
                }
                else
                        A[$1 FS $2] += $3
        }
        END {
                for ( k in A )
                        print k, A[k]
        }
' file