title: GULP: gulp is not defined
body: <p>As shown in the screen shot below I am not able to run <code>gulp</code> to concat the JavaScript files. Its saying that <code>gulp is not defined</code>.</p>
  
  <p>I have tried the following commands:</p>
  
  <pre><code>npm install -g gulp
  npm install gulp
  npm install gulp --save-dev
  </code></pre>
  
  <p>I have also set the environment variables as following:</p>
  
  <pre><code>C:\Users\&lt;user&gt;\AppData\Roaming\npm;C:\Python27;C:\Users\&lt;user&gt;\AppData\Roaming\npm\node_modules;C:\Users\&lt;user&gt;\AppData\Roaming\npm\node_modules\gulp;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/sBHxM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sBHxM.png" alt="enter image description here"></a></p>
  
  <pre><code>var concat = require('gulp-concat');  
  var rename = require('gulp-rename');  
  var uglify = require('gulp-uglify');  
  
  
  //script paths
  var jsFiles = 'scripts/*.js',  
      jsDest = 'dist/scripts';
  
  gulp.task('scripts', function() {  
      return gulp.src(jsFiles)
          .pipe(concat('scripts.js'))
          .pipe(gulp.dest(jsDest));
  });
  </code></pre>