a console.log replacement that prints callee file name and line

main.js

// this goes in the main file
// (assumes that all the modules that use this function are in the same directory or below)
// the Error.stack trick suggested by isaacbw on #Node.js on freenode

global.log = function() {
	var line = new Error().stack.match(/at .+\n/g)[1]
	var filename = line.match(/\((.+?\.js:\d+)/)[1].replace(__dirname, '').slice(1)
	var args = [].slice.call(arguments)
	args.unshift('[%s]', filename)
	console.log.apply(this, args)
}

// and so
var foo = require('./lib/foo')

// then, in module lib/foo.js
global.log('hey')
// prints "[lib/foo.js:42] hey"