hideMessage_textstego2.py

import sys
import os

def to_binary_string(s):
    binary_s = ''
    for c in s:
        binary_s += '{:08b}'.format(ord(c))
    return binary_s

def main():
    if len(sys.argv) != 4:
        print 'Usage: python %s <input-file> <message> <output-file>' % sys.argv[0]
        exit(1)

    input_file   = sys.argv[1]
    message      = sys.argv[2]
    output_file  = sys.argv[3]

    if not os.path.exists(input_file):
        print 'File "%s" does not exist' % input_file
        exit(1)

    message_hex = message.encode('hex')

    with open(input_file) as f:
        container = f.read()

    lines = container.split('\n')

    for i in range(len(message_hex)):
        lines[i] += ' ' * int(message_hex[i], 16)

    with open(output_file, 'w') as f:
        f.write('\n'.join(lines))

if __name__ == '__main__':
    main()