test

scripts/update-toc.sh

@@ -7,6 +7,24 @@
 ## Requires: https://github.com/mzlogin/vim-markdown-toc
 set -eu
 
+usage(){
+  echo "Usage: ${0##*/} <file> [file ...]"
+  exit 1
+}
+
+case "${1-}" in
+  ""|-h|--?help) usage;;
+esac
+
+## vim-markdown-toc deletes lines if they are folded, can't rely on its native
+## update on save.
+if ! vim -e -c 'setf markdown' -c 'if !exists(":GenTocGFM") | cq | endif' -c q
+then
+  echo "Error: Vim Plugin mzlogin/vim-markdown-toc is not installed."
+  exit 1
+fi
+
+
 for f in "$@"; do
   if ! grep -q "^## Table of Contents$" "$f"; then
     echo "Could not find table of contents on file: $f" >&2; exit 1