service/documentation.md

@@ -39,6 +39,42 @@ To make changes there, just clone and push to this git repository:
 
     git clone git@gitlab.torproject.org:tpo/tpa/wiki-replica.git
 
+Ideally, you should also setup linting locally, see below.
+
+## Local linting configuration
+
+While the wiki replica has continuous integration checks, it might be
+good to run those locally, to make sure you don't add any new warnings
+when making changes.
+
+We currently only lint Markdown syntax, with [markdownlint](https://github.com/markdownlint/markdownlint). You
+can install it using the upstream instructions, but anarcat prefers to
+run it under Docker, with a wrapper script like:
+
+    #!/bin/sh
+
+    exec docker run --volume "$PWD:/data/" --rm -i markdownlint/markdownlint "$@"
+
+Drop this somewhere in your path as `mdl` and it will behave just as
+if it was installed locally.
+
+Then you should drop this in `.git/hooks/pre-commit` (if you want to
+enforce checks):
+
+```
+#!/bin/bash
+
+${GIT_DIR:-.git}/../bin/mdl-wrapper $(git diff --cached --name-only HEAD)
+```
+
+... or `.git/hooks/post-commit` (if you just want warnings):
+
+```
+#!/bin/sh
+
+${GIT_DIR:-.git}/../bin/mdl-wrapper $(git diff-tree --no-commit-id --name-only -r HEAD)
+```
+
 ## Pager playbook
 
 ### Wiki unavailable