What is in bash var=64#@_
<p>I have the net line    </p>

<pre><code>let "b64 = 64#@_" # the result is 4011    
echo "b64 = $b64" # is 4011    
</code></pre>

<p>How did we get this result.
Does anybody knows what base notation is and how we got this result? Where can I read about this notation?</p>