title: how to run gulp tasks in order?
body: <p>I am trying to concat all the css files into one released css file by running task: </p>
  
  <pre><code>gulp.task('task one', () =&gt; {  
      gulp.src([Dir + "**/*.css"])
          .pipe(concat(outFilename + ".css"))
          .pipe(gulp.dest(destDir));
  });
  </code></pre>
  
  <p>After that, because the font path in the output css file is not correct, so I need to modify the path. </p>
  
  <pre><code>gulp.task('task two', () =&gt; {
      var urlAdjuster = require('gulp-css-url-adjuster');
  
      //change font path for released css files
      gulp.src([releasePath + "/*.css"])
          .pipe(urlAdjuster({
              replace: ['../../fonts', '../fonts'],
          }))
          .pipe(gulp.dest(releasePath + "/"));
  );
  </code></pre>
  
  <p>In order to make it happen, I need to run these two tasks separately one by one. 
  How can I run these two tasks in order and put them into one task. </p>
  
  <p>I have tried: 
  <code>series = require('gulp-series');</code> ----not working</p>
  
  <pre><code>gulp.task('task two', ['task one'], function () {
      // Gulp. src (...
  });
  </code></pre>
  
  <p>-----not working</p>
  
  <p>---update--------------------------------------------------------
  I used return but it is now working. The actual codes are: </p>
  
  <pre><code>function procHTMLForRelease(stream, file) {
      gulp.src([Dir + "**/*.css"])
          .pipe(concat(outFilename + ".css"))
          .pipe(gulp.dest(destDir));
  
  }
  
  function processRelease() {
  
  
      // Grab all html files in the folder.
      // Loop over them, process them, then spit em out.
      gulp.src([paths.Source + "/*.html"])
          .pipe(foreach(procHTMLForRelease))
          .pipe(gulp.dest(paths.Release));
  
      // Process image files
      gulp.src([paths.Source + "images/*.*"])
          .pipe(gulp.dest(paths.Release + "images/"));
  
      // Copy font files
      gulp.src([paths.html + "fonts/*.*", paths.html + "fonts/*/*.*"])
          .pipe(gulp.dest(paths.release + "/fonts/"));
  
  
  }  
  
  
  
  gulp.task('task one', () =&gt; { return processRelease();
  });
  </code></pre>