Question

I have 2 files that looks like this:

file1

aaa 5
bbb 2
ccc 9
ddd 46
eee 89
fff 56

file 2

aaa 54
bbb 8
ccc 16
ddd 4
eee 66
fff 9

I would like to have the sum of specific columns
(for example sum of aaa in both files
and sum of ccc + sum of ddd
and sum of bbb + sum of eee + sum of fff)

Is there a simple way to do so with awk for example?

Answer 1

If you simply want the sums, this can be done in pure bash (using associative arrays here, so bash 4 is required):

declare -A sums
while read name val1 val2; do
  sums[$name]=$(( val1 + val2 ))
done < <(join -j 1 file1 file2)

echo "Sum of aaa: ${sums[aaa]}"
echo "Sums of ccc and ddd: $(( ${sums[ccc]} + ${sums[ddd]} ))"
echo "Sums of bbb, eee, and fff: $(( ${sums[bbb]} + ${sums[eee]} + ${sums[fff]} ))"