title: Batch script if else command
body: <p>I'm trying to make a simple batch script to wipe/zero a flash drive and reformat it. It's for others, so i'm attempting to make it relatively safe, by blocking formatting to C:, D:, etc.</p>
  
  <p>I'm looking for an IF ELSE type command i can use, to be an error catch-all.</p>
  
  <p>Here's (the main portion of) what i have ATM</p>
  
  <pre><code>:again
  echo.
  cls
  echo.
  echo  Please select the drive letter for the flash
  echo  drive you wish to erase
  echo.
  echo    **** DO NOT SELECT C: OR D: ****
  echo.
  echo.
  echo   *** Enter letter (no colon) ONLY e.g. "E" ***
  echo.
  set /p answer=
  cls
  echo.
  echo.
  echo.
  if /i "%answer:~,1%" EQU "e" format E: /x /fs:FAT32 /v:FORENSICS /p:2
  if /i "%answer:~,1%" EQU "f" format F: /x /fs:FAT32 /v:FORENSICS /p:2
  if /i "%answer:~,1%" EQU "g" format G: /x /fs:FAT32 /v:FORENSICS /p:2
  if /i "%answer:~,1%" EQU "h" format H: /x /fs:FAT32 /v:FORENSICS /p:2
  if /i "%answer:~,1%" NOT exist goto again &amp;&amp; echo    Please provide a valid drive letter for flash drive
  echo.
  </code></pre>
  
  <p>Now I know that </p>
  
  <pre><code>if /i "%answer:~,1%" NOT exist goto again &amp;&amp; echo    Please provide a valid drive letter for flash drive
  </code></pre>
  
  <p>is not valid syntax, but what could I use in order to achieve the same goal? I know there is a more effecient way to do this (e.g. instead of defining 4 variables for likely drive letters, put a single variable that listens to user input and accepts it if it exists.)</p>
  
  <p>This is my first foray into batch scripting (and scripting in general) and i'm learning on-the-fly, so  the "dumber" you can make it, the better.</p>
  
  <p>Thanks in advance.</p>