reverse.py

#!/usr/bin/env python
#
# Reverse order of lines.
# Author:  Yotam Medini  [email protected] -- Created: 2005/October/30
#

import sys

# Check for 2 parameters
if len(sys.argv) != 3:
    sys.stderr.write("I should be called with 2 parameters!\n")
    sys.stderr.write("Usage:  %s <oldfile> <newfile>\n" % sys.argv[0])
    sys.exit(1)

# Open files
fold = open(sys.argv[1], 'r') # open for read
fnew = open(sys.argv[2], 'w') # open for write

lines = []
line = fold.readline()
while line != '': # we did not finish reading
    lines = [line] + lines  # Last line read becomes first!
    line = fold.readline()
fold.close() # We don't need it anymore

li = 0
while li < len(lines):
    line = lines[li]
    fnew.write(line)  # Note that it has the '\n' already there.
    li = li + 1
fnew.close()

sys.exit(0)