broadcast

#!/usr/bin/env python3

"""Broadcasts the text argument string across every line of the input file.


Usage:

    cat in.txt | broadcast "This is a test"

Will output every line of in.txt, with the string "This is a test" as column one, tab-separated.

You can specify the index of the output field using the -i argument. The default is -1.
"""

import sys


def main(args):
    message = "\t".join(args.message)

    for line in args.infile:
        fields = line.rstrip().split("\t")
        if args.index >= 0 and args.index < len(fields):
            fields.insert(args.index, message)
        else:
            fields.append(message)

        print(*fields, sep=args.separator)


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser()
    parser.add_argument("--index", "-i", type=int, default=-1, help="which field to broadcast the message to (default: %(default)s)")
    parser.add_argument("--infile", type=argparse.FileType("r"), default=sys.stdin)
    parser.add_argument("--separator", "-d", "-t", default="\t")
    parser.add_argument("message", nargs="+")
    args = parser.parse_args()

    main(args)