diff --git a/release.nix b/release.nix
index 4186fd773..c2b272223 100644
--- a/release.nix
+++ b/release.nix
@@ -157,7 +157,7 @@ rec {
 
       preCheck = ''
         patchShebangs .
-        export LOGNAME=${LOGNAME:-foo}
+        export LOGNAME=''${LOGNAME:-foo}
       '';
 
       postInstall = ''