diff --git a/build.sh b/build.sh
index 290588b8cf6f..d8a0d6c18bac 100755
--- a/build.sh
+++ b/build.sh
@@ -17,7 +17,7 @@ usage()
     echo
 }
 
-if [ $1 == "-?" ]; then
+if [ "$1" == "-?" ]; then
     usage
 fi