diff --git a/.circleci/config.yml b/.circleci/config.yml
index 8639361..ac349ec 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -19,7 +19,7 @@ commands:
                 command: apk update
             - run:
                 name:    "Setup: Install build packages."
-                command: apk add git bash python2 diffutils ca-certificates curl
+                command: apk add git bash python2 diffutils ca-certificates curl shfmt
             - run:
                 name:    "Setup: Install test packages."
                 command: apk add util-linux coreutils