title: About looping through environment variables but looking for the first char in them
body: <p>I wrote this code,</p>
  
  <pre><code>set /p Letter=Enter your FavoriteLetter:
  if "%1" == "" (
     echo Usage: Enter Your Birth Date EX. (November)  
     exit /b 1
  ) 
  
  setlocal enableDelayedExpansion
  </code></pre>
  
  <p>What i would like to do is take the users letter that they entered and loop through all environment variables with a for loop, then return how many i found that start with the given letter they input. Please if you have the time do explain it to me i want to learn as well as find out the answer. </p>