shebang-regex 
Regular expression for matching a shebang
Install
$ npm install --save shebang-regex
Usage
var shebangRegex = require('shebang-regex');
var str = '#!/usr/bin/env node\nconsole.log("unicorns");';
shebangRegex.test(str);
//=> true
shebangRegex.exec(str)[0];
//=> '#!/usr/bin/env node'
License
MIT © Sindre Sorhus