diff --git a/Shorewall-core/configure b/Shorewall-core/configure
index 82a26ec40..38e8ab8dc 100755
--- a/Shorewall-core/configure
+++ b/Shorewall-core/configure
@@ -58,7 +58,7 @@ for p in $@; do
     pn=${p%=*}
     pv=${p#*=}
 
-    if [ -n ${pn} ]; then
+    if [ -n "${pn}" ]; then
 	case ${pn} in
 	    VENDOR)
 		pn=HOST
@@ -73,7 +73,7 @@ for p in $@; do
 		pn=CONFDIR
 		;;
 	esac
-	    
+    
 	params[${pn}]="${pv}"
     fi
 done