title: Parsing only first regex match in a line with several matches
body: <p>Is it possible to have a regex that parses only <code>a1bcdea1</code> from this line <code>a1bcdea1ABCa1DEFa1</code> ? </p>
  
  <p>This grep command does not work:</p>
  
  <pre><code>$ cat txtfile
  a1bcdea1ABCa1DEFa1
  $ grep -oE "[A-Z,a-z]1.*?[A-Z,a-z]1" txtfile
  a1bcdea1ABCa1DEFa1
  </code></pre>
  
  <p>I want the output of grep to be only <code>a1bcdea1</code>.</p>
  
  <p>EDIT: </p>
  
  <p>It is obvious that I can just use grep -o "a1bcdea1" for the above line, but consider if one has several thousands of lines and the goal is to match FIRST <code>[A-Z,a-z]1.*?[A-Z,a-z]1</code> for each single line.</p>