build your own app-specific REPL for a nodejs application http://derickbailey.com/2014/07/02/build-your-own-app-specific-repl-for-your-nodejs-app/

my-repl-2.js

// my-repl.js

var repl = require("repl");

var replServer = repl.start({
  prompt: "my-app > ",
});

replServer.context.foo = "bar";

my-repl.js

// my-repl.js

var repl = require("repl");

var replServer = repl.start({
  prompt: "my-app > ",
});

my-repl.txt

$ node my-repl
my-app > var foo = "bar";
undefined
my-app > foo
'bar'
my-app > var fs = require("fs")
undefined
my-app > 

repl-context.txt

$ node my-repl.js
my-app > foo
'bar'
my-app > 

repl.txt

$ node
> var foo = "bar";
undefined
> foo
'bar'
> var fs = require("fs")
undefined
> 

signalleaf-repl.js

var repl = require("repl");

// environment configuration
var epa = require("epa");

// database 
var db = require("db");

// app specific modules
var Podcasts = require("podcasts");
var Accounts = require("accounts");

// i love moment.js
var moment = require("moment");

// connect to the database
db.connect(epa.mongo, function(err){
  if (err){ throw err; }

  var envName = process.env.NODE_ENV || "dev";

  // open the repl session
  var replServer = repl.start({
    prompt: "SignalLeaf (" + envName + ") > ",
  });

  // attach my modules to the repl context
  replServer.context.epa = epa;
  replServer.context.db = db;
  replServer.context.Podcasts = Podcasts;
  replServer.context.Accounts = Accounts;
  replServer.context.moment = moment;
  
});