Range file

range.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys


def gen_byte(path):
    with open(path) as fd:
        while True:
            buf = fd.read(4096)
            if not buf:
                return
            for b in buf:
                yield b


def range_filter(path, start, end=-1):
    def write(s):
        sys.stdout.write(s)

    buf = []
    n = 0
    end = end if end >= 0 else sys.maxint
    for b in gen_byte(path):
        if n >= start:
            buf.append(b)
        n += 1
        if n > end:
            break
        if len(buf) > 4096:
            write(''.join(buf))
            buf = []
    if buf:
        write(''.join(buf))

path = sys.argv[1]
r = sys.argv[2].split('-')
if len(r) == 2:
    start, end = int(r[0]), int(r[1])
else:
    start, end = int(r[0]), -1

range_filter(path, start, end)