title: Combine multiple files into single file in unix shell scripting
body: <p>I want to combine the data of 3 (say) files having the same columns and datatype for those, into a single file, which I can further use for processing.<br>
  Currently I have to process the files one after the other. So, I am looking for a solution which I can write in a script to combine all the files into one single file.<br>
  For ex:<br>
  File 1:  </p>
  
  <pre><code>mike,sweden,2015
  tom,USA,1522
  raj,india,455
  </code></pre>
  
  <p>File 2:  </p>
  
  <pre><code>a,xyz,155
  b,pqr,3215
  c,lmn,3252
  </code></pre>
  
  <p>Expected combined file 3:  </p>
  
  <pre><code>mike,sweden,2015
  tom,USA,1522
  raj,india,455
  a,xyz,155
  b,pqr,3215
  c,lmn,3252
  </code></pre>
  
  <p>Kindly help me with this.</p>