title: Randomly mix lines of 3 million-line file
body: <p>Everything is in the title. I'm wondering if any one knows a quick and with reasonable memory demands way of randomly mixing all the lines of a 3 million lines file. I guess it is not possible with a simple vim command, so any simple script using Python. I tried with python by using a random number generator, but did not manage to find a simple way out.</p>