csv-add-column.py

import csv
import sys
import click


@click.command()
@click.option('--file-name', help='Input file (file is not modified).')
@click.option('--index', help='Insert column at this position (starts at 0).')
@click.option('--column-name', help='Column name.')
def main(file_name, index, column_name):
    with open(file_name, 'r') as f:
        reader = csv.reader(f)
        writer = csv.writer(sys.stdout)
        for i, row in enumerate(reader):
            if i == 0:
                row.insert(int(index), column_name)
            else:
                row.insert(int(index), '')
            writer.writerow(row)


if __name__ == '__main__':
    main()