diff --git a/ci/travis/check-git-clang-format-output.sh b/ci/travis/check-git-clang-format-output.sh
index 224de1fc3..6dc0b51ca 100755
--- a/ci/travis/check-git-clang-format-output.sh
+++ b/ci/travis/check-git-clang-format-output.sh
@@ -1,16 +1,16 @@
 #!/bin/bash
 
-if [ "$TRAVIS_PULL_REQUEST" == "false" ] ; then
+if [ -z "${TRAVIS_PULL_REQUEST-}" ] || [ "${TRAVIS_PULL_REQUEST}" = "false" ]; then
   # Not in a pull request, so compare against parent commit
   base_commit="HEAD^"
-  echo "Running clang-format against parent commit $(git rev-parse $base_commit)"
+  echo "Running clang-format against parent commit $(git rev-parse "$base_commit")"
 else
   base_commit="$TRAVIS_BRANCH"
-  echo "Running clang-format against branch $base_commit, with hash $(git rev-parse $base_commit)"
+  echo "Running clang-format against branch $base_commit, with hash $(git rev-parse "$base_commit")"
 fi
 exclude_regex="(.*thirdparty/|.*redismodule.h|.*.java|.*.jsx?|.*.tsx?)"
-output=$(ci/travis/git-clang-format --binary clang-format --commit $base_commit --diff --exclude "$exclude_regex")
-if [ "$output" == "no modified files to format" ] || [ "$output" == "clang-format did not modify any files" ] ; then
+output="$(ci/travis/git-clang-format --binary clang-format --commit "$base_commit" --diff --exclude "$exclude_regex")"
+if [ "$output" = "no modified files to format" ] || [ "$output" = "clang-format did not modify any files" ] ; then
   echo "clang-format passed."
   exit 0
 else