title: how to manipulate SREC file
body: <p>I have an S19 file looking something like below:</p>
  
  <pre><code>S0030000FC
  S30D0003C0000F0000000000000020
  S3FD00000000782EFF1FB58E00003D2B00003D2B00003D2B00003D2B00003D2B00003D
  S3ED000000F83D2B00003D2B00003D2B00003D2B00003D2B00003D2B00003D2B00003D
  S31500000400FFFFFFFFFFFFFFFFFFFFFFFF7EF9FFFF7D
  S3FD0000041010B5DFF828000468012147F22C10C4F20300016047F22010C4F2030000
  S70500008EB4B8
  </code></pre>
  
  <p>I want to separate the first two characters and also the next two characters, and so on... I want it to look like below (last two characters are also to be separated for each line):</p>
  
  <pre><code>S0, 03, 0000, FC
  S3, 0D, 0003C000, 0F00000000000000, 20
  S3, FD, 00000000, 782EFF1FB58E00003D2B00003D2B00003D2B00003D2B00003D2B0000, 3D
  S3, ED, 000000F8, 3D2B00003D2B00003D2B00003D2B00003D2B00003D2B00003D2B0000, 3D
  S3, 15, 00000400, FFFFFFFFFFFFFFFFFFFFFFFF7EF9FFFF, 7D
  S3, FD, 00000410, 10B5DFF828000468012147F22C10C4F20300016047F22010C4F20300, 00
  S7, 05, 00008EB4, B8
  </code></pre>
  
  <p>How can I do this in Python?
  I have something like this:</p>
  
  <pre><code> #!/usr/bin/python
   import string,os,sys,re,fileinput
   print "hi"
   inputfile = "k60.S19"
   outputfile = "k60_out.S19"
  
   # open the source file and read it
   fh = file(inputfile, 'r')
   subject = fh.read()
   fh.close()
  
   # create the pattern object. Note the "r". In case you're unfamiliar with Python
   # this is to set the string as raw so we don't have to escape our escape characters
  
   pattern2 = re.compile(r'S3')
   pattern3 = re.compile(r'S7')
   pattern1 = re.compile(r'S0')
   # do the replace
   result1 = pattern1.sub("S0, ", subject)
   result2 = pattern2.sub("S3, ", subject)
   result3 = pattern3.sub("S7, ", subject)
  
   # write the file
   f_out = file(outputfile, 'w')
  
   f_out.write(result1)
   f_out.write(result2)
   f_out.write(result3)
   f_out.close()
  
   #EoF
  </code></pre>
  
  <p>but it is not working as I like!! Can someone help me with how to come up with proper regular expression use for this?</p>