diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0a35e000..af98aca6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
       run: shellcheck -V  && shellcheck -e SC2181 **/*.sh && echo "shellcheck OK"
     - name: Install shfmt
       with:
-        SHFMT_URL=https://github.com/mvdan/sh/releases/download/v3.1.2/shfmt_v3.1.2_linux_amd64
+        SHFMT_URL: "https://github.com/mvdan/sh/releases/download/v3.1.2/shfmt_v3.1.2_linux_amd64"
       run: curl -sSL ${{ SHFMT_URL }} -o ~/shfmt && chmod +x ~/shfmt
     - name: shfmt
       run: ~/shfmt -l -w -i 2 . ; git diff --exit-code && echo "shfmt OK"