npm

Getting Started

List everything you have installed in the current directory npm ls
Search the registry for packages matching terms npm search [search terms]
Install a package npm install [<name> [<name> ...]] [--save\|--save-dev\|--save-optional] This command installs a package, or packages, and any packages that it depends on in the current directory. If the package has a shrinkwrap file, the installation of dependencies will be driven by that. If no `package.json` exists, these options are ignored. If it exists, they'll update them if they are already there. `--save`: Package will appear in your depedencies. `--save-dev`: Package will appear in your devDependencies. `--save-optional`: Package will appear in your optionalDependencies. `--global`: Package will be installed globally (if you want to use it as a command line tool for example)
Install a package in the version npm install <module-name>@<version-name>
Uninstall a package, completely removing everything npm installed on its behalf npm uninstall
Update all the packages listed to the latest version (specified by the tag config). Also install missing packages npm update [<name> [<name> ...]]
Update the global npm version npm update npm -g
Display the README.md / documentation / npmjs.org page of a give library npm docs <module-name>
Run package test suite, based on setup in package.json in "scripts" : {"test" : "node testfile.js"}
List outdated libraries compared to currently installed node_modules npm outdated
Lock down dependency versions npm shrinkwrap

Develop

Interactively create a package.json file npm init Asks you a bunch of questions, and then writes a package.json for you. If you already have a package.json file, it'll read that first, and default to the options in there.
Install a git specific release npm install git://github.com/Marak/colors.js#v0.6.0
Locally edit a dependency npm edit <module_name>
Setup editor for npm edit npm config set editor "sublime"
Publish a package not under the default "latest" tag npm publish --tag beta