Basic Python implementation of the unix tail command

tail.py

#! /usr/bin/env python
'''
Copyright (c) 2012 Marcus McCurdy
Permission is hereby granted, free of charge, to any person 
obtaining a copy of this software and associated documentation 
files (the "Software"), to deal in the Software without restriction, 
including without limitation the rights to use, copy, modify, merge, 
publish, distribute, sublicense, and/or sell copies of the Software, 
and to permit persons to whom the Software is furnished to do so, 
subject to the following conditions:

The above copyright notice and this permission notice shall be 
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY 
KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE 
AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
DEALINGS IN THE SOFTWARE.
Created 8/22/12
@author: Marcus McCurdy <marcus.mccurdy@gmail.com>
'''

import os, sys, argparse

def tail(path, lines_to_print=5):
    if lines_to_print < 1:
        return
    with open(path, 'r') as file:
        file.seek(-1, os.SEEK_END)
        position = file.tell()
        lines_seen = 0
        if file.read(1) == '\n':
            position -= 1
            file.seek(position)
        while lines_seen < lines_to_print and file.tell() > 0:
            c = file.read(1)
            if c == '\n':
                lines_seen += 1
                if lines_seen == lines_to_print:
                    break
            position -= 2
            file.seek(position)
        sys.stdout.write(file.read())



if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('path', help='The path to the file to tail')
    parser.add_argument('-n', help='Print the last n lines of the file', type=int, default=5)
    args = parser.parse_args()
    tail(args.path, args.n)