import itertools import sys for x, y in zip(open(sys.argv[1]), open(sys.argv[2])): for xc, yc in itertools.izip_longest(x.rstrip('\r\n'), y.rstrip('\r\n'), fillvalue=' '): if yc == ' ': sys.stdout.write(xc); else: sys.stdout.write(yc); sys.stdout.write('\n')