diff --git a/external-sys76.sh b/external-sys76.sh
index 0975929..a7bba33 100644
--- a/external-sys76.sh
+++ b/external-sys76.sh
@@ -22,7 +22,7 @@ echo 'deb [arch=amd64 trusted=yes] https://ppa.launchpadcontent.net/system76-dev
 apt update -y --allow-unauthenticated
 
 PPP=$(../../ppp https://ppa.pika-os.com/dists/lunar/external/binary-amd64/Packages https://ppa.launchpadcontent.net/system76-dev/pre-stable/ubuntu/dists/lunar/main/binary-amd64/Packages.xz)
-if [ ! -z $PPP ]
+if [ ! -z "$PPP" ]
 then
     apt download $PPP -y
 else