diff --git a/src/boot.sh b/src/boot.sh
index 7704712..0f8d8fd 100644
--- a/src/boot.sh
+++ b/src/boot.sh
@@ -102,7 +102,7 @@ fi
 SM_BIOS=""
 PS="/sys/class/dmi/id/product_serial"
 
-if [ -s "$PS"] && [ -r "$PS" ]; then
+if [ -s "$PS" ] && [ -r "$PS" ]; then
 
   BIOS_SERIAL=$(<"$PS")
   BIOS_SERIAL="${BIOS_SERIAL//[![:alnum:]]/}"