hideMessage_textstego3.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]

    message_binary = to_binary_string(message)

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

    lines = container.split('\n')
    print 'Lines: %d' % len(lines)
    print 'Bits in message: %d' % len(message_binary)

    message_binary += '0' * (len(lines) - len(message_binary))
    for i in range(len(message_binary)):
        if message_binary[i] == '0':
            lines[i] += '\r\n' #CRLF
        else:
            lines[i] += '\n\r' #LFCR

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


if __name__ == '__main__':
    main()