I am very new to Bash scripting and still at the learning stage. Currently, I am working on CSV files and there has been a requirement that if 2 rows are matched in 2 different CSV files, then the data column should be added.

For example,

csv_file1.csv:

Account,Entity,Data
A1101,E101,1000

csv_file2.csv:

Account,Entity,Data
A1101,E101,2000
A1101,E102,2000

On executing bash script, the expected output should be a new CSV file with rows:

Account,Entity,Data
A1101,E101,3000
A1101,E102,2000

Since, elements in 1st row of “csv_file1” and elements in 1st row of “csv_file2” are matching, data in the “Data” column should append.

The below is the code which I have tried to print the contents of both CSV files. But, I am not able to move forward from here.

#!/bin/bash
#assigns the CSV file to a variable
FILE1="csv_file1.csv"

#reads each line and splits it into three variables

while IFS=, read -r Account Entity Data; do

echo "$Account#""$Entity#""$Data"

done < <(tail -n +2 $FILE1)

#assigns the CSV file to a variable
FILE2="csv_file2.csv"

#reads each line and splits it into three variables

while IFS=, read -r Account Entity Data; do

echo "$Account#""$Entity#""$Data"

done < <(tail -n +2 $FILE2)

It would be great if you guys can help me with your ideas. please let me know if any additional information is needed. Thanks a lot in Advance!