diff --git a/.pre-commit b/.pre-commit
new file mode 100644
index 0000000..b5aef27
--- /dev/null
+++ b/.pre-commit
@@ -0,0 +1,11 @@
+#!/bin/sh
+FILES=$(git diff --cached --name-only --diff-filter=ACMR | sed 's| |\\ |g')
+[ -z "$FILES" ] && exit 0
+
+# Prettify all selected files
+echo "$FILES" | xargs keep-sorted
+
+# Add back the modified files to staging
+echo "$FILES" | xargs git add
+
+exit 0
diff --git a/README.md b/README.md
index 4b13b1c..fd970aa 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,11 @@
-# dots
\ No newline at end of file
+# dots
+## build
+### `keep-sorted` pre-commit hook
+copy the pre-commit hook to `.git/hooks`
+```bash
+cp .pre-commit .git/hooks/pre-commit
+```
+make it executable
+```bash
+chmod +x .git/hooks/pre-commit
+```