Shell Programming and Scripting

#!/bin/bash

while IFS="," read f1_ID f1_VER f1_COST
do
        [[ "$f1_ID" =~ ID ]] && continue;

        while IFS="," read f2_ID f2_VER f2_COST
        do
                [[ "$f2_ID" =~ ID ]] && continue;

                if [ $f1_ID -eq $f2_ID ]
                then
                        if [ $f1_ID -eq $f2_ID ] && [ $f1_VER -eq $f2_VER ] && [ $f1_COST -eq $f2_COST ]
                        then
                                continue;
                        fi
                        [[ $f1_VER -ne $f2_VER ]] && printf "${f1_ID},version,${f1_VER},${f2_VER}\n"
                        [[ $f1_COST -ne $f2_COST ]] && printf "${f1_ID},cost,${f1_COST},${f2_COST}\n"
                fi
        done < file2.csv
done < file1.csv

join -t"," -1 1 -2 1 -a1 file1.csv file2.csv | awk -F, ' BEGIN {
         print "ID,field,old,new"
 } NF > 3 { 
        if ( $3 != $5 )   
              print $1, "cost", $3, $5        
       if ( $2 != $4 )              
            print $1, "version", $2, $4 } ' OFS=, 

echo "the IDs which are not present in first file are ">>file3000.csv 
awk -F, 'NR==FNR{_1[$1]++;next}!_1[$1]' file81.csv file82.csv >> file3000.csv 
cut -d',' -f1 file3000.csv>>file3001.csv 
cat file3001.csv  

echo "the IDs which are not present in second file are ">>file4000.csv 
awk -F, 'NR==FNR{_1[$1]++;next}!_1[$1]' file82.csv 
file81.csv >> file4000.csv cut -d',' -f1 file4000.csv>>file4001.csv 
cat file4001.csv