title: Calling shell functions with xargs
body: <p>I am trying to use xargs to call a more complex function in parallel.  </p>
  
  <pre><code>#!/bin/bash
  echo_var(){
      echo $1
      return 0
  }
  seq -f "n%04g" 1 100 |xargs -n 1 -P 10 -i echo_var {} 
  exit 0
  </code></pre>
  
  <p>This returns the error</p>
  
  <pre><code>xargs: echo_var: No such file or directory
  </code></pre>
  
  <p>Any ideas on how I can use xargs to accomplish this, or any other solution(s) would be welcome.</p>