Consider this python program:
import sys lc = 0 for line in open(sys.argv[1]): lc = lc + 1 print lc, sys.argv[1]
Running it on my 6GB
Note that Python I/O is implemented in C, so there is not much luck speeding it up further.
If you assume that a disk can read 60MB/s you'd need 6000 / 60 = 100 seconds, which is 1 minute 40 seconds. I don't think that you can get any faster because the disk is the bottleneck.