gistfile1.py

import readin
import sys

if len(sys.argv) < 2:
  print "No Input"
elif len(sys.argv) < 3:
	print "No Output"
else: 
	t = readin.readDataFromFile(sys.argv[1])
	#print t
	u = str()
	for i in t:
		if i == "T":
			u = u + "U"
		else: 
			u = u + i

	#print u

	out = open(sys.argv[2], 'w') # 'w' opens in "write" mode, which erases existing content of the file
	print >> out, u
	out.close()