title: grep on strace only working with stderr to stdout
body: <p>when i do:</p>
  
  <pre><code>sudo strace -p PID 2&gt;&amp;1 | grep -v "recvmsg"
  </code></pre>
  
  <p>grep matches the lines it ought to match, but when i do:</p>
  
  <pre><code>sudo strace -p PID|grep -v "recvmsg"
  </code></pre>
  
  <p>It still shows all calls.
  Why is that?</p>