title: How do I remove non numeric characters from only one column of a .csv file in bash?
body: <p>I have a large .csv file containing inconsistent data that looks something like this:</p>
  
  <pre><code>O_T_11c,234858DEF8,OHL11_c_234858DEF8.csv,c
  Ohl12und,234858DEF8,OHL12_u234858DEF8.csv,u
  Ohlabx13und,234858DEF8,OHL13u_234858DEF8.csv,u
  Ohl14und,234858DEF8,OHL14u_234858DEF8.csv,u
  </code></pre>
  
  <p>I want to remove the all letters only from only the first column and leave the rest alone. I've attempted to do this using a regex in awk, but this gives me
  strange output. I want my output to ultimately be this:</p>
  
  <pre><code>11,234858DEF8,OHL11_c_234858DEF8.csv,c
  12,234858DEF8,OHL12_u234858DEF8.csv,u
  13,234858DEF8,OHL13u_234858DEF8.csv,u
  14,234858DEF8,OHL14u_234858DEF8.csv,u
  </code></pre>
  
  <p>I understand I can use a sed like this</p>
  
  <pre><code>sed 's/[^0-9]*//g'
  </code></pre>
  
  <p>To remove all non-numeric characters, but I only want to apply this to the first column.</p>