Fast Search for text or pattern in memory mapped file

searchFile.py

#!/usr/bin/python2.7
import re, mmap, os, contextlib, sys

#print "Usage:    ./s1.py file regex(to print)"
# print "Example:  ./s1.py /tmp/a.log 10.213.194.\S+:http://([^/]+)/"

myString = str(sys.argv[2])
print "Searching file: " , str(sys.argv[1])
fn = sys.argv[1]
size = os.stat(fn).st_size

re.compile(myString)

with open(fn, 'r+') as f:
  data = mmap.mmap(f.fileno(), size)
  for match in re.finditer(myString, data, re.S):
    print match.group(0)