title: Remove dot(.) from specific columns using gsub and awk
body: <p>I want to remove dot(.) only from the 4th and 5th columns of the table.</p>
  
  <pre><code>input
  1    10057   .       A       AC      
  1    10146   .       AC.      A       
  1    10177   .       A       AC      
  1    10230   .       AC      .A,AN    
  1    10349   .       CCCTA   C,CCCTAA.              
  1    10389   .       .AC      A,AN
  
  
  
  desired output
  1    10057   .       A       AC      
  1    10146   .       AC      A       
  1    10177   .       A       AC      
  1    10230   .       AC      A,AN    
  1    10349   .       CCCTA   C,CCCTAA              
  1    10389   .       AC      A,AN    
  </code></pre>
  
  <p>So I tried the following command.</p>
  
  <pre><code>awk 'BEGIN {OFS=FS="\t"} {gsub("\.","",$4);gsub("\.","",$5)}1' input
  </code></pre>
  
  <p>and I got this result (The whole 4th and 5th columns were removed).</p>
  
  <pre><code>1    10057   .          
  1    10146   .            
  1    10177   .        
  1    10230   .       
  1    10349   .                 
  1    10389   .       
  </code></pre>
  
  <p>Can you please point out where I have to modify?
  Thanks in advance.</p>