中国DOS联盟

@echo off
findstr /v "aa" a.txt>b.txt

@echo off
setlocal enabledelayedexpansion
>"b.txt" type nul
for /f "usebackq tokens=*" %%a in ("a.txt") do (
  set row=%%a
  if "!row:~10,2!" equ "XX" (
    >>"b.txt" echo %%a
  )
)

@echo off
setlocal enabledelayedexpansion
>"b.txt" type nul
for /f "usebackq tokens=*" %%a in ("a.txt") do (
  set row=%%a
  if /i "!row:~10,2!" equ "XX" (
    >>"b.txt" echo %%a
  )
)

@echo off
setlocal enabledelayedexpansion
set count=0
>a.txt type nul
for /f "tokens=1-2 delims=:" %%a in ('findstr /n .* b.txt') do (
  set /a count+=1
  if !count! equ 5 (
    >>a.txt echo.aa=qweeeerttyy
  )
  if "%%b" equ "" (
    >>a.txt echo.
  ) else (
    >>a.txt echo.%%b
  )
)