How to Add Column with Percentage

Question

I would like to calculate percentage of value in each line out of all lines and add it as another column. Input (delimiter is \\t):

1   10      
2   10
3   20
4          


        

Answer 1

You can do it in a couple of passes

#!/bin/bash

total=$(awk '{total=total+$2}END{print total}' file)
awk -v total=$total '{ printf ("%s\t%s\t%.2f\n", $1, $2, ($2/total)*100)}' file