title: Tcpdump with -w writing gibberish to file
body: <p>When trying to capture tcpdump output to a file, I get the following:</p>
  
  <p>▒ò▒▒▒▒3▒X▒▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒Xu&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒D&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒D&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X5▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b
  7
  7▒▒3▒X▒&lt;&lt;▒▒▒▒▒▒▒4▒4▒b</p>
  
  <p>If I run tcpdump without the -w the output displays fine in the shell.</p>
  
  <p>Here is the input:</p>
  
  <pre><code>tcpdump -i eth0 -Z root -w `date '+%m-%d-%y.%T.pcap'`
  </code></pre>