diff --git a/entrypoint.sh b/entrypoint.sh
index 84217159..f86a576f 100644
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -56,19 +56,19 @@ printf "TinyProxy version: $(tinyproxy -v | cut -d" " -f2)\n"
 ############################################
 [ "$PORT_FORWARDING" == "false" ] && PORT_FORWARDING=on
 [ "$PORT_FORWARDING" == "true" ] && PORT_FORWARDING=off
-if [ -z $TINYPROXY && ! -z $PROXY ]; then
+if [ -z $TINYPROXY ] && [ ! -z $PROXY ]; then
   TINYPROXY=$PROXY
 fi
-if [ -z $TINYPROXY_LOG && ! -z $PROXY_LOG_LEVEL ]; then
+if [ -z $TINYPROXY_LOG ] && [ ! -z $PROXY_LOG_LEVEL ]; then
   TINYPROXY_LOG=$PROXY_LOG_LEVEL
 fi
-if [ -z $TINYPROXY_PORT && ! -z $PROXY_PORT ]; then
+if [ -z $TINYPROXY_PORT ] && [ ! -z $PROXY_PORT ]; then
   TINYPROXY_PORT=$PROXY_PORT
 fi
-if [ -z $TINYPROXY_USER && ! -z $PROXY_USER ]; then
+if [ -z $TINYPROXY_USER ] && [ ! -z $PROXY_USER ]; then
   TINYPROXY_USER=$PROXY_USER
 fi
-if [ -z $TINYPROXY_PASSWORD && ! -z $PROXY_PASSWORD ]; then
+if [ -z $TINYPROXY_PASSWORD ] && [ ! -z $PROXY_PASSWORD ]; then
   TINYPROXY_PASSWORD=$PROXY_PASSWORD
 fi
 
@@ -101,7 +101,7 @@ if [ "$DOT" == "off" ]; then
   fi
 fi
 exitIfNotIn PORT_FORWARDING "on,off"
-if [ "$PORT_FORWARDING" == "on" && -z "$PORT_FORWARDING_STATUS_FILE" ]; then
+if [ "$PORT_FORWARDING" == "on" ] && [ -z "$PORT_FORWARDING_STATUS_FILE" ]; then
   printf "PORT_FORWARDING is on but PORT_FORWARDING_STATUS_FILE is not set\n"
   exit 1
 fi