Something keeps nibbling on my list

[michael]

My program reads a file and copies it into a list, line by
line. Then
writes the list to another file. for some reason the first 2
lines from
the first file are missing from the second file. i know that
they are
being read into the list because i print the whole list out
and they are
there. Can someone please help? The entire program is below.

     TIA
            Michael

################  Start program #######################


#!/usr/local/bin/python

#This program reads the hosts.deny file, removes duplicate entries and
#sorts them. It then sends the output to another file.
#This program requires Python 2.0.

import sys
import string

FILENAME = "/etc/hosts.deny"   #The file the input is read from.
TEMPFILE = "./hosts.deny.test"   #The file the output is written to.
EXCLUDE=''   #Lines beginning with this should not be printed.

def get_line() :
  buf = f.readline()
  if (buf and buf[0] == EXCLUDE):
    return 0
  else:
    return buf


def is_this_a_dup(buf, l) :
  if (l and buf):
    results = l.count(buf)
    if (results > 0):
      return l
    else:
      l.append(buf)
      return l
  else:
    l = buf
    return l


f = open(FILENAME, "r")

l = ["1"]   #This is just to avoid the "NameError: There is no
            #   variable named 'l'". It can be taken care of later.

while 1:
  buf = get_line()
  if (buf == ''):
    break
  if (buf == 0):   # If 0 is returned then the line read on this loop
begins
    continue       #    with the EXCLUDE char and is not to be used.
  else:
#    sys.stdout.write(buf)
    l = is_this_a_dup(buf, l)

print l

l.remove("1")   #Removes the 1 that we put into the list at the
beginning of
                #    the program.
l.sort()

for i in l:
  sys.stdout.write(i)

g = open(TEMPFILE, "w")
g.writelines(l)
g.close()

f.close()