diff --git a/nix/test-fake-ship.nix b/nix/test-fake-ship.nix
index 521f9cfbfc..26f5d68bd4 100644
--- a/nix/test-fake-ship.nix
+++ b/nix/test-fake-ship.nix
@@ -102,7 +102,7 @@ in pkgs.stdenvNoCC.mkDerivation {
   '';
 
   checkPhase = ''
-    if egrep "((FAILED|CRASHED|Failed|[0 %avow 0 %noun 1])|warn:)" $out >/dev/null; then
+    if egrep "((FAILED|CRASHED|Failed|\[0 %avow 0 %noun 1\])|warn:)" $out >/dev/null; then
       exit 1
     fi
   '';