My workflow for updating wallpaper previews in my nordic-wallpapers repository

main.yml

name: Update previews

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

  workflow_dispatch:

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2

      - name: Get list of wallpapers
        run: ls wallpapers/ > wallpaper-preview.md
        
      - name: Add markdown syntax for image preview on each line
        run: |
          sed -i -e 's/^/![](wallpapers\//' wallpaper-preview.md
          sed -i 's/$/\)/' wallpaper-preview.md
      - name: Add heading and an empty line
        run: |
          sed -i '1 i\# Wallpapers in this repository' wallpaper-preview.md
          sed -i '/# Wallpapers/ a \ ' wallpaper-preview.md
      - name: Commit wallpaper-preview.md
        uses: EndBug/add-and-commit@v7.4.0
        with:
          message: 'Auto updated preview'
      - name: Push changes  # push the output folder to your repo
        run: echo 'I ran'
      - uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          force: true