diff --git a/modules/workflows.nix b/modules/workflows.nix
index ef90a30..03eb6a0 100644
--- a/modules/workflows.nix
+++ b/modules/workflows.nix
@@ -133,7 +133,7 @@ in
         ${optionalString cfg.removeUnknown ''
           # Remove unknown workflow files
           for file in $(ls "$GIT_WC/.${cfg.platform}/workflows" | ${getExe pkgs.gnugrep} -v '\(${
-            concatMapStringsSep "|" (name: "${name}.yaml") (attrNames cfg.workflows)
+            concatMapStringsSep "\\|" (name: "${name}.yaml") (attrNames cfg.workflows)
           }\)'); do
             rm "$GIT_WC/.${cfg.platform}/workflows/$file" && echo "nix-actions: Removed $file"
           done