Index: utils/novnc_proxy
--- utils/novnc_proxy.orig
+++ utils/novnc_proxy
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/ksh
 
 # Copyright (C) 2018 The noVNC authors
 # Licensed under MPL 2.0 or any later version (see LICENSE.txt)
@@ -118,14 +118,8 @@ fi
 
 # Sanity checks
 if [ -z "${HOST}" ]; then
-    if bash -c "exec 7<>/dev/tcp/localhost/${PORT}" &> /dev/null; then
-        exec 7<&-
-        exec 7>&-
-        die "Port ${PORT} in use. Try --listen PORT"
-    else
-        exec 7<&-
-        exec 7>&-
-    fi
+    netstat -ln -p tcp | grep -qs "\.${PORT} .*LISTEN" \
+        && die "Port ${PORT} in use. Try --listen PORT"
 fi
 
 trap "cleanup" TERM QUIT INT EXIT
@@ -169,38 +163,7 @@ if [ -n "${KEY}" ]; then
     fi
 fi
 
-# try to find websockify (prefer local, try global, then download local)
-if [[ -d ${HERE}/websockify ]]; then
-    WEBSOCKIFY=${HERE}/websockify/run
-
-    if [[ ! -x $WEBSOCKIFY ]]; then
-        echo "The path ${HERE}/websockify exists, but $WEBSOCKIFY either does not exist or is not executable."
-        echo "If you intended to use an installed websockify package, please remove ${HERE}/websockify."
-        exit 1
-    fi
-
-    echo "Using local websockify at $WEBSOCKIFY"
-else
-    WEBSOCKIFY_FROMSYSTEM=$(which websockify 2>/dev/null)
-    WEBSOCKIFY_FROMSNAP=${HERE}/../usr/bin/python2-websockify
-    [ -f $WEBSOCKIFY_FROMSYSTEM ] && WEBSOCKIFY=$WEBSOCKIFY_FROMSYSTEM
-    [ -f $WEBSOCKIFY_FROMSNAP ] && WEBSOCKIFY=$WEBSOCKIFY_FROMSNAP
-
-    if [ ! -f "$WEBSOCKIFY" ]; then
-        echo "No installed websockify, attempting to clone websockify..."
-        WEBSOCKIFY=${HERE}/websockify/run
-        git clone https://github.com/novnc/websockify ${HERE}/websockify
-
-        if [[ ! -e $WEBSOCKIFY ]]; then
-            echo "Unable to locate ${HERE}/websockify/run after downloading"
-            exit 1
-        fi
-
-        echo "Using local websockify at $WEBSOCKIFY"
-    else
-        echo "Using installed websockify at $WEBSOCKIFY"
-    fi
-fi
+WEBSOCKIFY=/usr/local/bin/websockify
 
 # Make all file paths absolute as websockify changes working directory
 WEB=`realpath "${WEB}"`
