title: How to do it correctly: grep -ri '->'
body: <pre><code>cat a.txt | grep -ri '-&gt;'
  </code></pre>
  
  <p>I want to grep lines with text arrow ->. 
  But in linux shell
   <code>-</code> means starts of an option<br>
  and 
    <code>&gt;</code> means pipe output to a file.  </p>
  
  <p>So after doing command given above ,I got error  </p>
  
  <pre><code>[root@rs169 document_root]# cat a.txt | grep -ri '-&gt;'
  grep: invalid option -- '&gt;'
  Usage: grep [OPTION]... PATTERN [FILE]...
  Try `grep --help' for more information.
  </code></pre>
  
  <p>Can someone tell how to do it correctly?</p>