Lineman is a node.js-based tool that greatly facilitates writing Javascript-based web applications. Lineman was created by Justin Searls, co-founder of the software studio Test Double. This is a short howto aiming at conveying how easy it is to get a webapp up and running with Lineman.

Start by installing Lineman (I'm just going to blatantly assume that you've already installed node.js):

sudo npm install -g lineman

and now you're able to create a scaffolded project as a starting point:

lineman new proj
cd proj/

where proj is the name of your new project. If everything went well, you should be able to do

lineman run

and open up localhost:8000 in your favourite browser to see a well-known greeting. In another terminal window, do

lineman spec

and Lineman will start the Testem runner. Now you can start editing your test files (spec/*.js) and source files (app/js/*.js), and whenever you save a file, Lineman will both run your tests and update the application running on localhost:8000.

The really cool thing with Testem is that you can run the tests in several browsers at the same time, simply by accessing the URL shown by Testem, which usually is localhost:7357. This even works on other machines, for example on Android phones or tablets connected to your local network (but in that case you of course have to replace localhost in the URL with your IP number).

Lineman has out-of-the-box support for Coffeescript, and since it's based on grunt, you can add support for other languages as well. Another nifty feature is backend proxying, which is described in more detail in the official documentation, but basically it enables you to specify the port on which you're running your backend server, and Lineman will automatically proxy requests that it doesn't handle itself to the specified port. Real simple and very powerful.