title: How to replace in stream using Gulp?
body: <p>I try to switch from Grunt to Gulp and I have an issue:</p>
  
  <p>I read two streams from two files</p>
  
  <pre><code>var fileStream = gulp.src(file);
  var injectionStream = gulp.src(injection)
  .pipe(replace('#class-name#', argv.cname));
  </code></pre>
  
  <p>If my console argument "--remove" is absent I have no problem to concatenate these streams</p>
  
  <pre><code>.pipe(concat('animation.styl'))
  .pipe(gulp.dest('./dist'))
  </code></pre>
  
  <p>However when '--remove' is true I want to delete injection, in other words, subtract injectionStream from fileStream.</p>
  
  <p>I tried:</p>
  
  <pre><code>var es = require('event-stream');
  es.replace()
  
  var replace = require('gulp-replace');
  </code></pre>
  
  <p>It works with strings, but I cannot succeed with streams read from files. Can anybody give me a small hint?</p>
  
  <p>And maybe it is an incorrect tool for generation task and I should stay with Grunt and\or other tools like yo,etc?<br>
  Thank you for your time!</p>