Mine

import sys
from optparse import OptionParser

usage = "usage: %prog [options] filename"
parser = OptionParser(usage=usage)

parser.add_option("-n", default=1, type="int",
    help="Number of lines to print from file")
parser.add_option("-l", default=False, action="store_true",
    help="Print line numbers")
(options, args) = parser.parse_args()
if len(args) != 1:
    parser.error("incorrect number of arguments")
chunk   = options.n
lineNumToggle = options.l
f = open(args[0], 'r')

lineCount = 0
while f:  # not detecting eof
	i = 0
	while (i != chunk) and f:
		line = f.readline()
		if not line:	break
		if lineNumToggle:
			print lineCount,
			lineCount += 1
		print line
		i += 1
	if not line:	break	
	raw_input('Hit any key to continue')