updatefile.js
function updateExample(app, str) {
  var cwd = app.options.dest || app.cwd;
  return app.src('example.txt', {cwd: cwd})
    .pipe(append(str))
    .pipe(app.dest(cwd));
}
function updateExample(app, str) {
  var cwd = app.options.dest || app.cwd;
  return app.src('example.txt', {cwd: cwd})
    .pipe(append(str))
    .pipe(app.dest(cwd));
}
function updateExample ( app , str ) { var cwd = app . options . dest || app . cwd ; return app . src ( 'example.txt' , { cwd : cwd } ) . pipe ( append ( str ) ) . pipe ( app . dest ( cwd ) ) ; }
Append the given string to `example.txt` and re-write the file to the current
working directory.

The `.src` and `.dest` methods work exactly like gulp's (we use the same libs from the
gulp team under the hood)

@param {Object} `app` Instance of update, to get the cwd. Pass `--dest` on the command line to set `app.options.dest`
@return {Stream} vinyl stream
@api public
Append the given string to example . txt and re - write the file to the current working directory .