findit.py

import time

find = '07123E1F482356C415F684407A3B8723E10B2CBBC0B8FCD6282C49D37C9C1ABC'
length = len(find)

# dd if=/dev/urandom of=200mb.txt bs=1000000 count=200
# echo '07123E1F482356C415F684407A3B8723E10B2CBBC0B8FCD6282C49D37C9C1ABC' >> 200mb.txt
data = open('200mb.txt').read()

found = 0
start = time.time()
i = 0
for i in xrange(len(data)):
    if data[i] == find[found]:
        found += 1
    else:
        found = 0

    if found == length:
        print 'found at ', i
        found = 0

print 'scan took', time.time() - start