diff --git a/.build.yml b/.build.yml
index be29941..83c8a95 100644
--- a/.build.yml
+++ b/.build.yml
@@ -30,10 +30,7 @@ tasks:
 
   # Diff RSS template against Hugo default, make sure only differences are intentional
   - rss: |
-      curl -s https://raw.githubusercontent.com/gohugoio/hugo/refs/tags/v$HUGO_VERSION/tpl/tplimpl/embedded/templates/rss.xml \
-        | diff - ./themes/v2/layouts/_default/rss.xml \
-        | wc -l \
-        | grep 7
+      ./bin/check-rss-template
 
   # Start Ruby server for dithering images
   - dither: |
diff --git a/.gitea/workflows/deploy.yaml b/.gitea/workflows/deploy.yaml
index ff8055c..758d806 100644
--- a/.gitea/workflows/deploy.yaml
+++ b/.gitea/workflows/deploy.yaml
@@ -33,11 +33,7 @@ jobs:
           printf '%s' "$SECRET_KEY" > secret.key
 
       - name: Verify RSS template diff
-        run: |
-          curl -s https://raw.githubusercontent.com/gohugoio/hugo/refs/tags/v${HUGO_VERSION}/tpl/tplimpl/embedded/templates/rss.xml \
-            | diff - ./themes/v2/layouts/_default/rss.xml \
-            | wc -l \
-            | grep 7
+        run: ./bin/check-rss-template
 
       - name: Build site
         run: ./bin/build
diff --git a/bin/check-rss-template b/bin/check-rss-template
new file mode 100755
index 0000000..882a3a6
--- /dev/null
+++ b/bin/check-rss-template
@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
+tmp_dir=$(mktemp -d)
+trap 'rm -rf "${tmp_dir}"' EXIT
+
+hugo_version="${HUGO_VERSION:?HUGO_VERSION must be set}"
+upstream_template="${tmp_dir}/rss.xml"
+diff_output="${tmp_dir}/rss.diff"
+
+curl -fsSL "https://raw.githubusercontent.com/gohugoio/hugo/refs/tags/v${hugo_version}/tpl/tplimpl/embedded/templates/rss.xml" \
+	-o "${upstream_template}"
+
+set +e
+diff "${upstream_template}" "${repo_root}/themes/v2/layouts/_default/rss.xml" >"${diff_output}"
+diff_status=$?
+set -e
+
+if [[ "${diff_status}" -gt 1 ]]; then
+	exit "${diff_status}"
+fi
+
+line_count=$(wc -l <"${diff_output}" | tr -d ' ')
+if [[ "${line_count}" != "7" ]]; then
+	echo "Unexpected RSS template diff line count: ${line_count}" >&2
+	cat "${diff_output}" >&2
+	exit 1
+fi