title: Add text between two patterns in File using sed command
body: <p>I want to add Some large code between two patterns:</p>
  
  <p><strong>File1.txt</strong></p>
  
  <pre><code>This is text to be inserted into the File.
  </code></pre>
  
  <p><strong>infile.txt</strong></p>
  
  <pre><code>Some Text here
  First
  Second
  Some Text here
  </code></pre>
  
  <p>I want to add <strong>File1.txt</strong> content between <em>First</em> and <em>Second</em> :</p>
  
  <p>Desired Output:</p>
  
  <pre><code>Some Text here
  First
  This is text to be inserted into the File.
  Second
  Some Text here
  </code></pre>
  
  <p>I can search using two patterns with sed command ,But I don't have idea how do I add content between them.</p>
  
  <pre><code>sed '/First/,/Second/!d' infile 
  </code></pre>