Hopefully this will help (using your input file) #!/usr/bin/env python import re buildinfo = "input.txt" input = open(buildinfo, 'r') regex = re.compile(r"^\s*build.number=(\d+)\s*$") for line in input: if re.search(regex, line): print line buildNum = re.sub(r"^\s*build.number=(\d+)\s*$", "\\1", line) print line print buildNum