import csv, sys

def main(fielddef=None, *inputs):

    if fielddef is None or len(inputs) == 0:
        sys.stderr.write("usage: %s <field_def> input_file [ ... ]\n" % sys.argv[0])
        return 1

    fields = map(lambda x: int(x) - 1, fielddef.split(','))

    fh = [open(f) for f in inputs]
    readers = []

    for f in fh:
        dialect = csv.Sniffer().sniff(f.readline())
        f.seek(0)
        readers.append(csv.reader(f,dialect))

    writer = csv.writer(sys.stdout)

    for row in zip(*readers):
        output = []
        for fileno, filerow in enumerate(row):
            for i in fields:
                try:
                    output.append(filerow[i])
                except IndexError:
                    sys.stderr.write("* Error: Could not find column %d in the following row from %s:\n" % (i + 1, inputs[fileno]))
                    sys.stderr.write("* %s\n" % str(filerow))
                    return 1
        writer.writerow(output)

    map(lambda f: f.close(), fh)

    return 0

if __name__ == "__main__":
    sys.exit(main(*sys.argv[1:]))