Hex reading problems

[BossOfTheGame]

I have a huge binary file and I want to quicky edit it with a python script.
I want to search the file for the bytes

54 45 58 30 00 00 20 40 00 00 00 01 FF FF FE E0
00 00 00 40 00 04 CF 44 00 00 00 00 00 80 00 80
00 00 00 0E 00 00 00 01 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

or the string

TEX0 @
ÿÿþÃ*@Ã�D€€

and replace all the bytes after that to the next occurrence of the string with a different hex file that I want to read in.

I'm having problem reading in these huge (534kb) files. When I say huge I mean to big to edit by hand. I'm not familiar with hex or how its read. The literal string that I copied from my hex editor was turned into that when it looks nothing like that in the actual editor.

[ifdef]

Open the file as binary

f = open('filename', 'rwb')
lostString = string # Lost because we are searching for it ;) but seriously this is a list of hex e.g. 0xAB
count = 0
while count != len(lostString):
    if f.read(1) == lostString[count]:
        count += 1
    else:
        count = 0

This should put you at your byte then you just have to modify that byte and shift the rest of the data down.

Also refrence http://snippets.dzone.com/posts/show/740