CMD Challenge

This repository contains the code for the site cmdchallenge.com

Read more about cmdchallenge

Installation

• Install Docker
• Install rtx
• rtx install

docker-compose build runcmd cmd cmd-no-bin
# For ARM (M1 mac for example) run
#   BUILD_ARCH=arm64 docker-compose build runcmd cmd cmd-no-bin

docker-compose up --remove-orphans
# For ARM (M1 mac for example) run
#   BUILD_ARCH=arm64 docker-compose up runcmd caddy -V --remove-orphans

# Connect your browser to http://localhost:8181/

cmd and cmd-no-bin are runner images launched on demand by the Go server. They use the runner-images Compose profile so a normal docker-compose up starts only the web server and Caddy. Build them explicitly as shown above; they are not long-running services.

• Connect your browser to http://localhost:8100

Testing

• cd cmdchallenge && go test ./...

• Frontend checks (from site/):

  npm ci
  npm run lint
  npm test
  npm run build
  npx playwright install chromium
  npm run test:browser

  Browser tests exercise the production build on desktop and mobile with mocked command/solutions responses; they do not require Docker.

Local development

Static assets

cd site
npm ci
npm run build

build.js bundles browser JavaScript and CSS with esbuild, compiles Sass, copies public/, and writes dist/index.html with content-hashed asset URLs. Production builds include precompressed gzip files for Caddy.

For development, run npm run dev from site/ to watch JavaScript, Sass, HTML, and public assets. Start the Go server in another terminal and refresh the browser after changes. Watch builds include source maps and skip minification/compression. Restart the watcher after changing build.js or installing dependencies.

Run the server

cd cmdchallenge
# Start the backend the `-dev` option uses an in-memory db.
go run cmd/runcmd/runcmd.go -dev -staticDistDir=../site/dist

Open http://localhost:8181/. The Go server serves both the built site and its API. The other flavors can be tested at http://oops.localhost:8181/ and http://12days.localhost:8181/ in browsers that resolve .localhost to loopback.

Frontend structure

The frontend uses native DOM APIs and ES modules. main.js loads styles and starts app.js, which coordinates challenge state, navigation, and requests. The command form in command-input.js provides history, completion, keyboard handling, and busy state. ui.js renders challenge content and feedback; api.js, storage.js, and router.js handle the browser interfaces.

Enter runs a command, Shift+Enter inserts a new line, Up/Down recalls history, and Tab completes a word. Double Tab displays matching candidates. Shift+Tab leaves the command field, and Tab on an empty field moves to the Run button. Existing correct_answers progress and jQuery Terminal history remain available.

Type clear (or press Ctrl+L) to clear the command field and displayed output locally. Ctrl+A and Ctrl+E move to the start and end of the current line; Ctrl+C cancels the current input when no text is selected, and copies selected text normally. These shortcuts apply only while the command field has focus.

Misc

Test a single command:

curl  http://localhost:8181/c/r -X POST -F slug=hello_world -F cmd="echo hello world"

Fetch solutions:

curl http://localhost:8181/c/s?slug=hello_world

Bugs / Suggestions

• Open a GitHub issue.