user15657: I have downloaded the latest version of Stockfish, and I am running it on the command line.
There is a hidden command 'd' which displays the current board.
Also, the "debug on" command is not implemented, even though it is part of the UCI protocol.
Is there a list somewhere of all commands, all "un-implemented" commands, and/or command line switches for Stockfish?
I have already downloaded and read the UCI protocol.
Before someone sugests it, I would like to write my own GUI, so downloading arena and just running it isn't an option.

user19871: I have created this gist which is the best documentation I could find - most links I found where dead
https://gist.github.com/aliostad/f4470274f39d29b788c1b09519e67372

user825: Look at the source code:

https://github.com/official-stockfish/Stockfish/blob/master/src/uci.cpp

   // Additional custom non-UCI commands, mainly for debugging
      else if (token == "flip")  pos.flip();
      else if (token == "bench") bench(pos, is, states);
      else if (token == "d")     sync_cout << pos << sync_endl;
      else if (token == "eval")  sync_cout << Eval::trace(pos) << sync_endl;

Your "d" command is there, and others.

15657: <p>I have downloaded the latest version of Stockfish, and I am running it on the command line.</p>

<p>There is a hidden command 'd' which displays the current board.
Also, the "debug on" command is not implemented, even though it is part of the UCI protocol.</p>

<p>Is there a list somewhere of all commands, all "un-implemented" commands, and/or command line switches for Stockfish?</p>

<p>I have already downloaded and read the UCI protocol.</p>

<p>Before someone sugests it, I would like to write my own GUI, so downloading arena and just running it isn't an option.</p>
 19871: <p>I have created this gist which is the best documentation I could find - most links I found where dead</p>

<p><a href="https://gist.github.com/aliostad/f4470274f39d29b788c1b09519e67372" rel="nofollow noreferrer">https://gist.github.com/aliostad/f4470274f39d29b788c1b09519e67372</a></p>
 825: <p>Look at the source code:</p>

<blockquote>
  <p><a href="https://github.com/official-stockfish/Stockfish/blob/master/src/uci.cpp" rel="noreferrer">https://github.com/official-stockfish/Stockfish/blob/master/src/uci.cpp</a></p>
</blockquote>

<pre><code>   // Additional custom non-UCI commands, mainly for debugging
      else if (token == "flip")  pos.flip();
      else if (token == "bench") bench(pos, is, states);
      else if (token == "d")     sync_cout &lt;&lt; pos &lt;&lt; sync_endl;
      else if (token == "eval")  sync_cout &lt;&lt; Eval::trace(pos) &lt;&lt; sync_endl;
</code></pre>

<p>Your "d" command is there, and others.</p>
