diff --git a/src/doc/rustc-dev-guide/ci/github_pages.sh b/src/doc/rustc-dev-guide/ci/github_pages.sh
index 603b280f9839..f5dd7898ba32 100644
--- a/src/doc/rustc-dev-guide/ci/github_pages.sh
+++ b/src/doc/rustc-dev-guide/ci/github_pages.sh
@@ -7,4 +7,6 @@ BOOK_DIR=book
 if [ "$TRAVIS_BRANCH" = master -a "$TRAVIS_PULL_REQUEST" = false ]; then
     mdbook build 
     ghp-import $BOOK_DIR
-fi
\ No newline at end of file
+else
+    echo Skipping 'mdbook build' because this is not master or this is just a PR.
+fi