diff --git a/nixos/modules/installer/tools/nixos-version.sh b/nixos/modules/installer/tools/nixos-version.sh
index 8727cd2f876f..39e34a3718cb 100644
--- a/nixos/modules/installer/tools/nixos-version.sh
+++ b/nixos/modules/installer/tools/nixos-version.sh
@@ -8,7 +8,7 @@ case "$1" in
     ;;
   --hash|--revision)
     if ! [[ @revision@ =~ ^[0-9a-f]+$ ]]; then
-      echo "$0: Nixpkgs commit hash is unknown"
+      echo "$0: Nixpkgs commit hash is unknown" >&2
       exit 1
     fi
     echo "@revision@"