#!/usr/bin/env python

import re
import sys
import os


def license():
	print '''
	This script is released under BSD license. 
	Copyright (c) 2006 Shantanu Mahajan
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions
	are met:
	1. Redistributions of source code must retain the above
	   copyright notice, this list of conditions and the following
	   disclaimer.
	2. Redistributions in binary form must reproduce the above
	   copyright notice, this list of conditions and the following
	   disclaimer in the documentation and/or other materials
	   provided with the distribution.
	3. The name of the author may not be used to endorse or
	   promote products derived from this software without specific
	   prior written permission.

	    THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
	    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
	    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
	    INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
	    EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	    '''
if len(sys.argv) != 2:
	print "Incorrect parameters passed"
	print "Usage:"
	print "\t"+sys.argv[0]+" <file>"
	print "\tWhere <file> is file from which e-mail addresses will be extracted"
	print "\tOr use '-stdin' to use STDIN or pipe from other command"
	print "\n\n"
	sys.exit(1)

p = re.compile('([a-z]|\d|_|\.)+@([a-z]|\d)+(\.(([a-z]|\d)*))*')
if sys.argv[1] == '-stdin':
	f=sys.stdin
elif os.path.isfile(sys.argv[1]):
	f = open(sys.argv[1])
else:
	print "File '"+sys.argv[1]+"' does not exists"
	sys.exit(1)

try:
	for line in f.readlines():
		iter = p.finditer(line)
		for match in iter:
			print match.group()
except KeyboardInterrupt:
	print "Keyboard interrupt. Aborting"
	sys.exit(2)