#!/usr/bin/env python3 import sys if __name__ == '__main__': if len(sys.argv) != 2: print(sys.argv[0], 'input_file') sys.exit(1) with open(sys.argv[1]) as f: ifile = f.read() if ifile != 'This is a text only input file.\n': print('Malformed input') sys.exit(1) print('This is a binary output file.')