customize gulp file

gulpfile.coffee

through = require('through2')

gulp.task 'src', ->
  gulp.src './src/*.coffee'
    .pipe coffee({bare: true})
    .pipe gulp.dest('./dest/')
    .pipe through.obj((file, encoding, callback) ->
      callback(null, doSomethingWithTheFile(file)) 
    )
    .on 'error', gutil.log