diff --git a/.github/workflows/check-and-test.yml b/.github/workflows/check-and-test.yml
new file mode 100644
index 0000000..f917c1b
--- /dev/null
+++ b/.github/workflows/check-and-test.yml
@@ -0,0 +1,17 @@
+name: Run checks and tests
+run-name: Run checks and tests ⚡️
+on:
+  push:
+    paths:
+      - '**.sh'
+jobs:
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Check out repository code
+        uses: actions/checkout@v4
+
+      - name: Run ShellCheck
+        uses: ludeeus/action-shellcheck@master
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..c670738
--- /dev/null
+++ b/README.md
@@ -0,0 +1,50 @@
+# update-brew-tap-toc-action
+
+This GitHub action reads the Homebrew tap folder and procduces a table of content.
+The list of formulae is then placed in the specified files.
+
+## Example
+
+An example workflow can look like.
+
+```yaml
+name: Update TOC
+run-name: Update TOC 🚀
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - Formula/*.rb
+      - README.md
+jobs:
+  update-toc:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+
+      - name: Update TOC
+        uses: qaware/update-brew-tap-toc-action@main
+
+      - name: Commit & Push changes
+        # Use some action that fits your needs
+```
+
+You can pass options.
+
+```yaml
+# ...
+steps:
+  - name: Update TOC
+    uses: qaware/update-brew-tap-toc-action@main
+    with:
+      formula-folder: Formula-cstm
+      replace-in: README.md,TOC.md,docs/content.adoc
+      replace-marker-start: '// START TOC'
+      replace-marker-end: '// END TOC'
+```
+
+## Maintainers
+
+* Alexander Eimer ([@aeimer](https://github.com/aeimer))
diff --git a/action.yml b/action.yml
new file mode 100644
index 0000000..f7503f4
--- /dev/null
+++ b/action.yml
@@ -0,0 +1,31 @@
+name: update-brew-tap-toc-action
+description: Reads the formulae stored in the tap (repo) and updates the list in the README
+author: aeimer
+inputs:
+  formula-folder:
+    description: The folder path from the repo root where the Formulae are placed
+    required: true
+    default: Formula
+  replace-in:
+    description: In which files should the TOC be updated. Eg. "README.md,docs/content.adoc"
+    required: true
+    default: README.md
+  replace-marker-start:
+    description: Where to replace the TOC starts
+    required: true
+    default: <!-- BEGIN TOC -->
+  replace-marker-end:
+    description: Where to replace the TOC ends
+    required: true
+    default: <!-- END TOC -->
+runs:
+  using: composite
+  steps:
+    - name: Update TOC
+      shell: bash
+      run: ${{ github.action_path }}/update-toc.sh
+      env:
+        INPUT_FORMULA_FOLDER: ${{ inputs.formula-folder }}
+        INPUT_REPLACE_IN: ${{ inputs.replace-in }}
+        INPUT_REPLACE_MARKER_START: ${{ inputs.replace-marker-start }}
+        INPUT_REPLACE_MARKER_END: ${{ inputs.replace-marker-end }}
diff --git a/update-toc.sh b/update-toc.sh
new file mode 100755
index 0000000..ad1af8c
--- /dev/null
+++ b/update-toc.sh
@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Enable debug - print commands
+#set -x
+
+#############
+# FUNCTIONS #
+#############
+
+function generateToc() {
+  programNameList=()
+
+  while read -r file; do
+    programName=$(cut -d@ -f1 <<<"$file" | sed 's/.rb//')
+    programNameList+=("$programName")
+  done < <(find "$INPUT_FORMULA_FOLDER" -maxdepth 1 -type f -name '*.rb' -exec basename {} \; | sort)
+
+  if [[ ${#programNameList[@]} == "0" ]]; then
+    programNameList=("_n/a (no formula found)_")
+  fi
+
+  printf "* %s\n" "${programNameList[@]}" | sort -u
+}
+
+###############
+# CHECK INPUT #
+###############
+
+echo "Checking input"
+if [[ -z "${INPUT_FORMULA_FOLDER:-}" ]]; then
+    echo "ERROR: No formula-folder defined"
+    exit 1
+fi
+echo "  formula-folder: $INPUT_FORMULA_FOLDER"
+
+if [[ -z "${INPUT_REPLACE_IN:-}" ]]; then
+    echo "ERROR: No replace-in defined"
+    exit 1
+fi
+echo "  replace-in: $INPUT_REPLACE_IN"
+
+if [[ -z "${INPUT_REPLACE_MARKER_START:-}" ]]; then
+    echo "ERROR: No replace-marker-start defined"
+    exit 1
+fi
+echo "  replace-marker-start: $INPUT_REPLACE_MARKER_START"
+
+if [[ -z "${INPUT_REPLACE_MARKER_END:-}" ]]; then
+    echo "ERROR: No replace-marker-end defined"
+    exit 1
+fi
+echo "  replace-marker-start: $INPUT_REPLACE_MARKER_END"
+
+#######
+# RUN #
+#######
+
+echo "Generating TOC..."
+toc=$(generateToc)
+echo "TOC:"
+echo "----"
+echo "$toc"
+echo "----"
+
+for file in ${INPUT_REPLACE_IN//,/ }; do
+    # https://stackoverflow.com/questions/2699666/replace-delimited-block-of-text-in-file-with-the-contents-of-another-file
+    sed -i -ne '/'"$INPUT_REPLACE_MARKER_START"'/ {p; r '<(cat <<<"$toc") -e ':a; n; /'"$INPUT_REPLACE_MARKER_START"'/ {p; b}; ba}; p' "$file"
+done