Update start-server.sh

scripts/start-server.sh

@@ -7,7 +7,7 @@ if [ ! -f ${STEAMCMD_DIR}/steamcmd.sh ]; then
 fi
 
 echo "---Update SteamCMD---"
-if [ "USERNAME" == "" ]; then
+if [ "${USERNAME}" == "" ]; then
     ${STEAMCMD_DIR}/steamcmd.sh \
     +login anonymous \
     +quit
@@ -18,8 +18,8 @@ else
 fi
 
 echo "---Update Server---"
-if [ "USERNAME" == "" ]; then
-    if [ "$VALIDATE" == "true" ]; then
+if [ "${USERNAME}" == "" ]; then
+    if [ "${VALIDATE}" == "true" ]; then
         ${STEAMCMD_DIR}/steamcmd.sh \
         +login anonymous \
         +force_install_dir $SERVER_DIR \
@@ -33,7 +33,7 @@ if [ "USERNAME" == "" ]; then
         +quit
     fi
 else
-    if [ "$VALIDATE" == "true" ]; then
+    if [ "${VALIDATE}" == "true" ]; then
         ${STEAMCMD_DIR}/steamcmd.sh \
         +login $USERNAME $PASSWRD \
         +force_install_dir $SERVER_DIR \