diff --git a/.github/workflows/test-matrix.yml b/.github/workflows/test-matrix.yml
index a6bb8e1..7c6df6e 100644
--- a/.github/workflows/test-matrix.yml
+++ b/.github/workflows/test-matrix.yml
@@ -1,5 +1,9 @@
 name: "ZUnit (Zsh matrix)"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 on:
   schedule:
     - cron: "0 3 * * 3"
diff --git a/.github/workflows/test-native.yml b/.github/workflows/test-native.yml
index 2198540..2993c81 100644
--- a/.github/workflows/test-native.yml
+++ b/.github/workflows/test-native.yml
@@ -1,5 +1,9 @@
 name: "ZUnit (native)"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: read
 
diff --git a/docker/utils.zsh b/docker/utils.zsh
index d7738ab..ec52892 100755
--- a/docker/utils.zsh
+++ b/docker/utils.zsh
@@ -1,4 +1,6 @@
 #!/usr/bin/env zsh
+# -*- mode: zsh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
+# vim: ft=zsh sw=2 ts=2 et
 
 # Functions to wrap container setup and initialization.