diff --git a/.github/workflows/update-script-timestamp-on-sh-change.yml b/.github/workflows/update-script-timestamp-on-sh-change.yml
index ee3caa578..5716e6b60 100644
--- a/.github/workflows/update-script-timestamp-on-sh-change.yml
+++ b/.github/workflows/update-script-timestamp-on-sh-change.yml
@@ -57,7 +57,8 @@ jobs:
       - name: Parse PR number from merge commit
         id: pr
         run: |
-          if [[ "$COMMIT_MSG" =~ #([0-9]+) ]]; then
+          re='#([0-9]+)'
+          if [[ "$COMMIT_MSG" =~ $re ]]; then
             echo "number=${BASH_REMATCH[1]}" >> "$GITHUB_OUTPUT"
           else
             echo "number=" >> "$GITHUB_OUTPUT"