diff --git a/pkgs/build-support/alternatives/blas/default.nix b/pkgs/build-support/alternatives/blas/default.nix
index b1dadf23c078..36708ce8841a 100644
--- a/pkgs/build-support/alternatives/blas/default.nix
+++ b/pkgs/build-support/alternatives/blas/default.nix
@@ -81,7 +81,7 @@ stdenv.mkDerivation {
   patchelf --set-rpath "$(patchelf --print-rpath $out/lib/libblas${canonicalExtension}):${lib.getLib blasProvider}/lib" $out/lib/libblas${canonicalExtension}
 '' else if stdenv.hostPlatform.isDarwin then ''
   install_name_tool \
-    -id libblas${canonicalExtension}
+    -id libblas${canonicalExtension} \
     -add_rpath ${lib.getLib blasProvider}/lib \
     $out/lib/libblas${canonicalExtension}
 '' else "") + ''