[文本处理] BAT批处理如何修改指定文本的某行？

@echo off&setlocal enabledelayedexpansion
for /d %%d in (D:\m\*) do (
pushd %%d
for /f "delims=" %%a in ('type b.txt') do (
set /a n+=1
if !n! equ 1 (
echo %%a>>b.txt
) else (
if !n! equ 20 (
for /f "delims=" %%i in ("    <add key="A23" value="1" />") do echo %%i>>b.txt
) else (
echo.%%a>>b.txt  
)
)
)
popd
set n=0
)
pause
复制代码

@echo off
set "s=    <add key="A23" value="1" />"
for /f "delims=" %%i in ('dir /a-d /b /s "D:\m\b.txt"') do (
    set n=0
    (for /f "usebackq delims=" %%a in ("%%i") do (
        set /a n+=1 & set "str=%%a"
        setlocal enabledelayedexpansion
        if !n! equ 20 (
            echo,!s!
        ) else (
            echo,!str!
        )
        endlocal
    ))>$
    move $ "%%i"
)
pause
复制代码