中国DOS联盟

@echo off&setlocal enabledelayedexpansion
type a.txt>b.txt
set n=-1
:1
for /f "delims=" %%a in (a.txt) do set/a n+=1&call :lp "%%a"
ping 127.1 /n 3 >nul &set n=-1&goto 1

:lp
if not !n! equ 0 (
  for /f "skip=%n% delims=" %%a in (b.txt) do (
   set /a m=!n!+1
   if not "%%a" equ "%~1" echo &echo 第!m!行改变
   goto :eof
)
)
for /f "delims=" %%a in (b.txt) do (
  if not "%%a" equ "%~1" echo &echo 第1行改变
  goto :eof
)

@echo off
fc a.txt b.txt>nul 2>nul
if errorlevel 1 echo a.txt已被改动!
pause>nul