title: Correct way to turn on Bluetooth discovery on Ubuntu command line
body: <p>Looks like there are two different options to put Bluetooth in discovery mode:</p>
  <p>First method:</p>
  <pre><code>$ sudo bluetoothctl
  #discoverable on
  #pairable on
  #agent on
  #default-agent
  </code></pre>
  <p>Second method:</p>
  <pre><code>$ sudo hciconfig hci0 piscan
  </code></pre>
  <p>Second method seems to be simpler. Is there any problem in using the second method? When does the first method make sense?</p>