diff --git a/pkgs/build-support/trivial-builders.nix b/pkgs/build-support/trivial-builders.nix
index 707c5da0931f..692ac6801dee 100644
--- a/pkgs/build-support/trivial-builders.nix
+++ b/pkgs/build-support/trivial-builders.nix
@@ -280,7 +280,7 @@ rec {
         #!${runtimeShell}
         set -o errexit
         set -o nounset
-        set- o pipefail
+        set -o pipefail
 
         export PATH="${lib.makeBinPath runtimeInputs}:$PATH"