git-pre-commit

#!/usr/bin/env bash
#
# git pre-commit hook: block a commit if it would introduce a broken Markdown link.
#
# Install:
#   cp examples/git-pre-commit .git/hooks/pre-commit
#   chmod +x .git/hooks/pre-commit
#
# It only checks the Markdown files you're actually committing (fast), using link-check.js.
# Bypass once with `git commit --no-verify` if you really must.
#
# Assumes link-check.js is at the repo root. Change SCRIPTS_DIR if it lives elsewhere.

set -euo pipefail

SCRIPTS_DIR="${SCRIPTS_DIR:-$(git rev-parse --show-toplevel)}"

# Staged, added/copied/modified Markdown files only.
mapfile -t staged < <(git diff --cached --name-only --diff-filter=ACM -- '*.md' '*.markdown')

if [ "${#staged[@]}" -eq 0 ]; then
  exit 0
fi

echo "pre-commit: checking links in ${#staged[@]} staged Markdown file(s)…"
if ! node "$SCRIPTS_DIR/link-check.js" "${staged[@]}"; then
  echo "✗ Broken Markdown link(s) found — commit blocked. Fix them or use 'git commit --no-verify'."
  exit 1
fi