diff --git a/GUIDE.md b/GUIDE.md
index 74a9018..2601742 100644
--- a/GUIDE.md
+++ b/GUIDE.md
@@ -58,3 +58,10 @@ class Mycheat(Hack):
 
 Please, use `black` before doing a pull request, as it's the formatter the
 project use.
+
+On Linux, you can copy the git hook stored in [githooks/](./githooks) who check
+the code, preventing any commit with bad formatting.
+
+```sh
+$ cp githooks/* .git/hooks/
+```
diff --git a/githooks/pre-commit b/githooks/pre-commit
new file mode 100755
index 0000000..77061ce
--- /dev/null
+++ b/githooks/pre-commit
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+python3 -m black --check .