cli/builtin/plugin.js
function(cb) {
            fs.exists(potterHome, function(exists) {
                if(exists) {
                    cb(null);
                } else {
                    mkdirp(potterHome, cb);
                }
            });
        }
function(cb) {
            fs.exists(potterHome, function(exists) {
                if(exists) {
                    cb(null);
                } else {
                    mkdirp(potterHome, cb);
                }
            });
        }
function ( cb ) { fs . exists ( potterHome , function ( exists ) { if ( exists ) { cb ( null ) ; } else { mkdirp ( potterHome , cb ) ; } } ) ; }
make sure the potter folder exists
make sure the potter folder exists