Replace old chills with new atomic chills. To read more about chills see: http://www.unicode.org/versions/Unicode5.1.0/#Malayalam_Chillu_Characters

atomic-chiller.py

#!python

"""
Replace old chills with new atomic chills.
To read more about chills see: http://www.unicode.org/versions/Unicode5.1.0/#Malayalam_Chillu_Characters
"""
import unicodedata
import codecs
import sys
import os.path

# Chill pairs
chills = {
  u'\u0D23\u0D4D\u200D': u'\u0D7A', # new chillu NN
  u'\u0D28\u0D4D\u200D': u'\u0D7B', # new chillu N
  u'\u0d30\u0d4d\u200d': u'\u0d7c', # new chillu R
  u'\u0D32\u0D4D\u200D': u'\u0D7D', # new chillu L
  u'\u0D33\u0D4D\u200D': u'\u0D7E', # new chillu LL
  u'\u0d15\u0D4D\u200D': u'\u0D7F', # new chillu K
}
#oldNT = u'\u0d28\u0d4d\u0D31'
#newNT = u'\u0D7B\u0D4D\u0D31'

# function to replace old chills with new ones
def replace_chills(string):
  for old_chill, new_chill in chills.iteritems():
    string=string.replace(old_chill, new_chill)
  
  return string
  
if  __name__ =='__main__':
  input_filename = sys.argv[1]
  output_filename = sys.argv[2]
  input_file = codecs.open(input_filename, mode='r', encoding='utf-8')
  output_file = codecs.open(output_filename, mode='w+', encoding='utf-8')
  # Read entire text and convert.
  output_file.write(replace_chills(input_file.read()))
  output_file.flush()
  output_file.close()
  input_file.close()