title: In F# what does the >> operator mean?
body: <p>I noticed in some code in this <a href="http://www.navision-blog.de/2009/12/12/christmas-tree-in-fsharp/" rel="noreferrer">sample</a> that contained the >> operator:</p>
  
  <pre><code>let printTree =
    tree &gt;&gt; Seq.iter (Seq.fold (+) "" &gt;&gt; printfn "%s")
  </code></pre>
  
  <p>What does the >> operator mean/do?</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Thanks very much, now it is much clearer.
  Here's my example I generated to get the hang of it:</p>
  
  <pre><code>open System
  open System.IO
  
  let read_lines path = File.ReadAllLines(path) |&gt; Array.to_list
  
  let trim line = (string line).Trim()
  let to_upper line = (string line).ToUpper()
  
  let new_list = [ for line in read_lines "myText.txt" -&gt; line |&gt; (trim &gt;&gt; to_upper) ]
  
  printf "%A" new_list
  </code></pre>