Get just the download speed via fast.com from the command line, suitable for logs. The infrastructure is provided by Netflix to make sure ISPs are not throttling their streaming movies. For execution time, speedtest runs about 60% faster than fasttest. In terms of information, speedtest provides more than fasttest, and is more accurate in measuring download speed. The code base for speedtest is more mature and receives more support and scrutiny, compared to that of fasttest.