pycat.py

#!/usr/bin/env python

from __future__ import division

import os
import sys
import time

def seconds_to_hms(sec):
    return "%d:%.2d:%.2d" % (sec // (60*60), sec // 60 % 60, sec % 60)

def main(filename):
    if not filename or filename == "-":
        file_size = None
        fp = sys.stdin
    else:
        file_size = os.stat(filename).st_size
        fp = open(filename, "rb")
    
    block_size = 100*1024
    count = 0
    last_count = 0
    last_ts = time.time()
    start_ts = time.time()
    while True:
        block = fp.read(block_size)
        if not block:
            break
        count += len(block)
        sys.stdout.write(block)

        now = time.time()
        if now - last_ts > 5:
            mb = count / (1024 * 1024)
            rate = (count - last_count) / (now - last_ts)
            mb_rate = rate / (1024 * 1024) 
            last_ts = now
            last_count = count
            eta = (file_size - count) / rate
            elapsed = now - start_ts
            if file_size:
                done_perc = 100 * count / file_size
                sys.stderr.write("%s %.3f MB of %.3f MB total = %.2f %% (%.3f MB/s) (ETA %s)\n" % (seconds_to_hms(elapsed), mb, file_size/(1024*1024), done_perc, mb_rate, seconds_to_hms(eta)))
            else:
                sys.stderr.write("%s %.3f MB (%.3f MB/s)\n" % (seconds_to_hms(elapsed), mb, mb_rate))
    
    if fp != sys.stdin:
        fp.close()

if __name__ == "__main__":
    main(sys.argv[1] if len(sys.argv[1]) > 1 else None)