Why can't bash recognize the existence of a socket file
<p>On a Linux box I want to check if a specific socket file exists. I know the socket files exists, but my checks in bash don't show that to me:</p>

<pre><code>$ ls -l /var/run/supervisor.sock
srwxrw-rw- 1 root root 0 Jun  3 13:30 /var/run/supervisor.sock  # &lt;== THE FILE EXISTS!!
$ if [ ! -f /var/run/supervisor.sock ]; then echo 'file does not exist!'; fi
file does not exist!
</code></pre>

<p>Why oh why can't bash see that the file exists?</p>