add linting script for documentation

.gitlab-ci.yml

@@ -224,6 +224,13 @@ teaspoon:
   script:
     - teaspoon
 
+lint-doc:
+  stage: test
+  image: "phusion/baseimage:latest"
+  before_script: []
+  script:
+    - scripts/lint-doc.sh
+
 bundler:audit:
   stage: test
   <<: *ruby-static-analysis

scripts/lint-doc.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+cd "$(dirname "$0")/.."
+
+# Use long options (e.g. --header instead of -H) for curl examples in documentation.
+grep --perl-regexp --recursive --color=auto 'curl (.+ )?-[^- ].*' doc/
+if [ $? == 0 ]
+then
+  echo '✖ ERROR: Short options should not be used in documentation!' >&2
+  exit 1
+fi
+
+echo "✔ Linting passed"
+exit 0
+