replace.py

import sys
import os

try:
  t = sys.argv[1]
	u = sys.argv[2]
	rnm = True if len(sys.argv) > 3 else False
	
	fl_st = sys.argv[0]
	fl_n = fl_st.rfind("\\")
	fl_name = fl_st[fl_n+1:]
	
except IndexError:
	print("Запускай так:")
	print('replace.py <Чт> <На чт замнить> [<Меняем>]')
	
else:
	flist = os.listdir("./")
	fcount = len(flist)

	for i in range(fcount):
		if not fl_name == flist[i]:
			newName = flist[i].replace(t,u)
			if rnm:
				os.rename(flist[i],newName)
			print(newName)