title: How to grep download speed from wget output?
body: <p>I need to download several files with <code>wget</code> and measure download speed.</p>
  
  <p>e.g. I download with</p>
  
  <pre><code>wget -O /dev/null http://ftp.bit.nl/pub/OpenBSD/4.7/i386/floppy47.fs http://ftp.bit.nl/pub/OpenBSD/4.7/i386/floppyB47.fs
  </code></pre>
  
  <p>and the output is</p>
  
  <pre><code>--2010-10-11 18:56:00--  http://ftp.bit.nl/pub/OpenBSD/4.7/i386/floppy47.fs
  Resolving ftp.bit.nl... 213.136.12.213, 2001:7b8:3:37:20e:cff:fe4d:69ac
  Connecting to ftp.bit.nl|213.136.12.213|:80... connected.
  HTTP request sent, awaiting response... 200 OK
  Length: 1474560 (1.4M) [text/plain]
  Saving to: `/dev/null'
  
  100%[==============================================================&gt;] 1,474,560    481K/s   in 3.0s
  
  2010-10-11 18:56:03 (481 KB/s) - `/dev/null' saved [1474560/1474560]
  
  --2010-10-11 18:56:03--  http://ftp.bit.nl/pub/OpenBSD/4.7/i386/floppyB47.fs
  Reusing existing connection to ftp.bit.nl:80.
  HTTP request sent, awaiting response... 200 OK
  Length: 1474560 (1.4M) [text/plain]
  Saving to: `/dev/null'
  
  100%[==============================================================&gt;] 1,474,560    499K/s   in 2.9s
  
  2010-10-11 18:56:06 (499 KB/s) - `/dev/null' saved [1474560/1474560]
  
  FINISHED --2010-10-11 18:56:06--
  Downloaded: 2 files, 2.8M in 5.9s (490 KB/s)
  </code></pre>
  
  <p>I need to grep the total download speed, that is, the string <code>490 KB/s</code>.
  How do I do this?</p>
  
  <p>P.S. May need to account for the case that we will actually download only one file, so there won't be final output starting with <code>FINISHED</code></p>