This is a python example for an easy way to search file lines for lines matching a specific regex. You need to pass the filename to search as the first argument.

python_line_matcher.py

#!/usr/bin/env python
 
import sys, re

# get first command line argument as filename
input_file = sys.argv[1]
 
# suck in file contents
with open(input_file) as f:
  content = f.readlines()

# strip newline characters
lines = [line.strip() for line in content]

# search through the file, line by line, print matching lines.
for line in lines:
 # this regex uses a back-reference. each set of parens is a saved match.
 # the '\1' references the first saved match
  matchObj = re.match( r'([A-Za-z0-9]+) => (12)?\1$', line)
  if matchObj:
    print "FOUND MATCH: ", matchObj.group()