Install Harp
To install Harp, you must first have Node.js, which can be installed on OS X, Windows, Linux, and SmartOS. Download it from the Node.js website.
First, install Node.js. Harp uses Node.js, but you don’t need to know about Node.js or even JavaScript to use Harp. Once it’s finished installing, you can install Harp using the mighty npm: Node.js’ package manager. You’ll use the command prompt to do this.
On OS X and Linux
Access the command prompt using the Terminal application. On OS X, it’s located in Applications → Utilities → Terminal. On Ubuntu, find it in Applications → Terminal. Then, run the following command:
sudo npm install -g harp
You may skip using sudo if you have the appropriate privileges.
On Windows
If you are using Windows, Node.js will have come with the Node.js Command Prompt application. Now, to install Harp via npm, type in:
npm install -g harp
Thats it! Now you are ready to start the harp webserver.
Updating Harp
Updating to the latest version of Harp is the same command as installing Harp. Run the following in your terminal:
npm install -g harp
You may need to preface this command with sudo, depending on your setup.
Troubles upgrading? Try clearing your cache
If you’re having trouble upgrading to the latest version of Harp, especially if you have recently upgraded npm, or are getting an error message like Error: Cannot find module 'minify', you might simply need to clear your npm cache:
npm uninstall -g harp
npm cache clear
npm install -g harp
You may need to use sudo before any of those, depending on your setup. It’s possible that an older dependency of Harp is cached on your system and not finding the new version or something. The npm cache clear part could take a while, depending on how much is cached. That should fix the problem, however!