Shell Programming and Scripting

I have two files that have the date field in common. I request your help with some script that divide each field value from file1 by the correspond field value of the file2 only when the field date is equal in both files. Thanks in advance !

This is a sample of the files

file 1

12/16/2010, 134.21, 134.23, 132.86, 133.81, 23463000
12/17/2010, 133.97, 134.63, 133.22, 134.2, 17213000
12/20/2010, 135.13, 135.44, 134.33, 135.11, 13129500
12/21/2010, 135.17, 135.78, 134.79, 135.32, 10235600
12/22/2010, 135.6, 135.7, 134.97, 135.05, 7300600
12/23/2010, 134.26, 134.9, 133.93, 134.66, 8700800

file 2

12/16/2010, 123.53, 124.26, 123.10, 124.17, 186003814
12/17/2010, 124.08, 124.46, 123.82, 124.3, 141075300
12/20/2010, 124.64, 124.9, 123.98, 124.6, 119085500
12/21/2010, 124.99, 125.47, 124.87, 125.39, 94965500
12/22/2010, 125.48, 125.82, 125.41, 125.78, 78878100
12/23/2010, 125.64, 125.78, 125.29, 125.6, 70053700

something like..

Code:

#! /usr/local/bin/bash
exec 6<f2
while IFS=, read v1 v2 v3 v4 v5 v6
do
        IFS=, read n1 n2 n3 n4 n5 n6 <&6
        if [ "$v1" = "$n1" ]; then
                echo $v1,$(echo "scale=2;$v2/$n2" | bc),$(echo "scale=2;$v3/$n3" | bc),$(echo "scale=2;$v4/$n4" | bc),$(echo "scale=2;$v5/$n5" | bc),$(echo "scale=2;$v6/$n6" | bc)
        fi
done < f1
6<&-

O/P for the given sample:

Code:

12/16/2010,1.08,1.08,1.07,1.07,.12
12/17/2010,1.07,1.08,1.07,1.07,.12
12/20/2010,1.08,1.08,1.08,1.08,.11
12/21/2010,1.08,1.08,1.07,1.07,.10
12/22/2010,1.08,1.07,1.07,1.07,.09

Note: I have changed the date for the last row to test and its ignored.

May be awk solution would be simpler.

Assuming every record will have 6 fields:

Code:

awk -F, 'NR==FNR{a[$1]=$2;b[$1]=$3;c[$1]=$4;d[$1]=$5;e[$1]=$6;next;}{if(a[$1]) print $1", "$2/a[$1]", "$3/b[$1]", "$4/c[$1]", "$5/d[$1]", "$6/e[$1]; else print $0;}' file2 file1