grep.py

#!/usr/bin/env python3

"""------------------------------------------------------------

Esse programa e um simulador basico do comando grep do UNIX

Programa 3 do curso de Python e Django.

------------------------------------------------------------"""

#Importacao
import sys

FOUND = 0
NOT_FOUND = 1
ERROR = 2

def find(search, filename):
	
	__file = open(filename)
		
	for line in __file:
		if search in line:
			yield line.strip()

	__file.close()

def main(args):
	
	try:
	
		search = args[1]
	
	except IndexError:
	
		print >>sys.stderr,("Usage: grep [OPTION]... PATTERN [FILE]...")
		return(ERROR)

	filenames = args[2:]

	ret = NOT_FOUND
	
	#iteracao
	for filename in filenames:
		
		try:
		
			for line in find(search, filename):
				print("%s:%s" % (filename, line))
				ret = FOUND
		
		except IOError, ex:
		
			print >>sys.stderr,("grep.py: %s: %s" %(ex.filename, ex.strerror))
			return(ERROR)

	return(ret)

args = sys.argv
ret = main(args)
sys.exit(ret)