bin/fume.js
function (next) {

        async.each(input, function (path, done) {
            fs.stat(path, function (err, stats) {
                if (err) return done(err);
                if (stats.isDirectory())
                    return done("Cannot have a directory as input");
                done();
            });
        }, next);

    }
function (next) {

        async.each(input, function (path, done) {
            fs.stat(path, function (err, stats) {
                if (err) return done(err);
                if (stats.isDirectory())
                    return done("Cannot have a directory as input");
                done();
            });
        }, next);

    }
function ( next ) { async . each ( input , function ( path , done ) { fs . stat ( path , function ( err , stats ) { if ( err ) return done ( err ) ; if ( stats . isDirectory ( ) ) return done ( "Cannot have a directory as input" ) ; done ( ) ; } ) ; } , next ) ; }
make sure no directories in the input list
make sure no directories in the input list