脚本示例

@echo off
set file="a.txt"

(for /f "delims=" %%a in ('findstr /n .* %file%') do (
  set var=%%a
  setlocal enabledelayedexpansion
  if "!var:*:=!" neq "" (
    for %%a in (A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) do (
      set var=!var:%%a=%%a!
    )
    echo;!var:*:=!
  ) else echo;
  endlocal
))>"%temp%\UPPERCASE"

move "%temp%\UPPERCASE" %file%