Bash iterate through fields of a TSV file and divide it by the sum of the column

I have a tsv file with several columns, and I would like to iterate through each field, and divide it by the sum of that column:

Input:

A    1    2    1
B    1    0    3

Output:

A    0.5    1    0.25
B    0.5    0    0.75

I have the following to iterate through the fields, but I am not sure how I can find the sum of the column that the field is located in:

awk -v FS='\t' -v OFS='\t' '{for(i=2;i<=NF;i++){$i=$i/SUM_OF_COLUMN}} 1' input.tsv

>Solution :

You may use this 2-pass awk:

awk '
BEGIN {FS=OFS="\t"}
NR == FNR {
   for (i=2; i<=NF; ++i)
      sum[i] += $i
   next
}
{
   for (i=2; i<=NF; ++i)
      $i = (sum[i] ? $i/sum[i] : 0)
}
1' file file

A       0.5     1       0.25
B       0.5     0       0.75