diff --git a/build.sh b/build.sh
index 5b0b7ba..6ca9190 100755
--- a/build.sh
+++ b/build.sh
@@ -176,7 +176,7 @@ log "Begin ${BASE_DIR}"
 
 for STAGE_DIR in ${BASE_DIR}/stage*; do
 	STAGE_DIR_NUM=$(echo $STAGE_DIR | grep -o -E "[0-9]+$")
-	if [[ (-n $RUN_STAGE && $STAGE_DIR_NUM -eq $RUN_STAGE) && $STAGE_DIR_NUM -le $MAX_STAGE ]]; then
+	if [[ (-z $RUN_STAGE || $STAGE_DIR_NUM -eq $RUN_STAGE) && $STAGE_DIR_NUM -le $MAX_STAGE ]]; then
 		run_stage
 	else
 		echo "Skipping ${STAGE_DIR}"