#!/usr/bin/env python
"""\
convert dos linefeeds (crlf) to unix (lf)
usage: dos2unix.py <input> <output>
"""
import sys
import os

if len(sys.argv[1:]) != 1:
  sys.exit(__doc__)

content = ''
outsize = 0
fpath = os.path.dirname(os.path.abspath(sys.argv[1]))
dfile = os.path.join(fpath, sys.argv[1]+"_chg")
with open(sys.argv[1], 'rb') as infile:
  content = infile.read()
with open(dfile, 'wb') as output:
  for line in content.splitlines():
    outsize += len(line) + 1
    output.write(line + '\n')

if ((len(content)-outsize) == 0):
  os.remove(dfile)    
else:
  os.remove(sys.argv[1])
  os.rename(dfile, sys.argv[1])

print("Done. Saved %s bytes." % (len(content)-outsize))