Example of accessing ghost's api. Check out core/server/routes/api.js for more routes you can hit.

ghost-api.js

var querystring = require('querystring');
var http = require('http');
var fs = require('fs');
var requester = require('request');

var postData = querystring.stringify({
    grant_type: "password",
    username: "your_email",
    password: "password",
    client_id: "ghost-admin"
});

var uriBase = '/ghost/api/v0.1/';

var requestOptions = {
    host: '127.0.0.1',
    port: 2368,
    path: uriBase + 'authentication/token',
    method: 'POST',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': postData.length,
        'Accept': 'application/json, text/javascript, */*; q=0.01',
        'X-Requested-With': 'XMLHttpRequest'
    }
};

var request = http.request(requestOptions, function(response) {
   response.setEncoding('utf8');
   var authData = '';
   response.on('data', function(chunk) {
       authData += chunk;
   })
   response.on('end', function() {
       console.log('Auth data');

       var authObject = JSON.parse(authData);

       console.log(authObject);

       var apiQuery = querystring.stringify({
           include: "roles"
       });

       requestOptions.headers.Authorization = authObject.token_type + ' ' + authObject.access_token;
       requestOptions.headers['User-Agent'] = 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36';
       requestOptions.headers.Referer = 'http://127.0.0.1:2368/ghost/4/';

       delete requestOptions.headers['Content-Type'];
       delete requestOptions.headers['Content-Length'];

       var apiOptions = {
           url: 'http://' + requestOptions.host + ':' + requestOptions.port + uriBase + '/tags',
           headers: requestOptions.headers
       };

       function callback(error, response, body) {
           if (!error && response.statusCode == 200) {
               var info = JSON.parse(body);
               console.log(info);
           }
       }

       requester(apiOptions, callback);
   });
});

request.write(postData);
request.end();

This was very helpful. Thank you!

Thanks works great. Any idea how I could update an existing post using the api? Also, create a new post.
Edit: Will look at core/server/routes/api.js :-)