$ npm help
Usage: npm <command>

where <command> is one of:
    add-user, adduser, apihelp, author, bin, bugs, c, cache,
    completion, config, deprecate, docs, edit, explore, faq,
    find, get, help, help-search, home, i, info, init, install,
    la, link, list, ll, ln, login, ls, outdated, owner, pack,
    prefix, prune, publish, r, rb, rebuild, remove, restart, rm,
    root, run-script, s, se, search, set, show, shrinkwrap,
    star, start, stop, submodule, tag, test, un, uninstall,
    unlink, unpublish, unstar, up, update, version, view,
    whoami

npm <cmd> -h     quick help on <cmd>
npm -l           display full usage info
npm faq          commonly asked questions
npm help <term>  search for help on <term>
npm help npm     involved overview

Specify configs in the ini-formatted file:
    /home/gv/.npmrc
or on the command line via: npm <command> --key value
Config info can be viewed via: npm help config

$ npm install --help
npm install <tarball file>
npm install <tarball url>
npm install <folder>
npm install <pkg>
npm install <pkg>@<tag>
npm install <pkg>@<version>
npm install <pkg>@<version range>

Can specify one or more: npm install ./foo.tgz bar@stable /some/folder
If no argument is supplied and ./npm-shrinkwrap.json is 
present, installs dependencies specified in the shrinkwrap.
Otherwise, installs dependencies from ./package.json.