title: How to cat files in linux vertically?
body: <p>I have n files containing one line and want to concatenate them:</p>
  
  <p><em>Input files:</em></p>
  
  <pre><code>file_1
  A B C
  
  file_2 
  1 2 3 
  </code></pre>
  
  <p><em>Desired console ouput result:</em> </p>
  
  <pre><code>A B C
  1 2 3 
  </code></pre>
  
  <p><strong>But with</strong>:</p>
  
  <pre><code>$ cat file_1 file_2 
  </code></pre>
  
  <p><em>I get</em>:</p>
  
  <pre><code>A B C1 2 3 
  </code></pre>