findstr /v ~ 123.txt

@echo off
type nul>"%temp%\123_tmp.txt"
for /f "delims=:" %%a in ('findstr /n .* "123.txt"') do (
  set RowNum=%%a
)
set /a TarRow=RowNum-7
for /f "tokens=1* delims=:" %%a in ('findstr /n .* "123.txt"') do (
  if %%a leq %TarRow% (
    set "str=%%b"
    setlocal enabledelayedexpansion
    if "!str:~0,1!" equ "~" (
      echo.!str:~1!>>"%temp%\123_tmp.txt"
    ) else (
      echo.!str!>>"%temp%\123_tmp.txt"
    )
    endlocal
  )
)
findstr "^[0-1][0-9]-[A-Z][A-Z][A-Z]-[0-9][0-9]" "123.txt">>"%temp%\123_tmp.txt"
move /y "%temp%\123_tmp.txt" "123.txt"

@echo off
cd.>b.txt
for /f "delims=" %%i in ('type "a.txt"^|find /v /c ""') do set /a n=%%i-5
    for /f "tokens=1* delims=:" %%i in ('findstr /n .* a.txt') do (
        setlocal enabledelayedexpansion
        if not "%%j"=="" (
        set str=%%j
        set str=!str:*^~=!
        >>b.txt echo.!str!
        if %%i equ %n% start b.txt&goto :eof
        )else >>b.txt echo.
)
pause

@echo off&setlocal enabledelayedexpansion
echo.1>nul 3>b.txt
for /f "tokens=1* delims=:" %%i in ('findstr /n .* "a.txt"') do (
     set/a n=%%i-7
     if not "%%j"=="" set var=%%j
)
for /f "tokens=1* delims=:" %%i in ('findstr /n .* "a.txt"') do (
       if not "%%j"=="" (
       set str=%%j
       set str=!str:*^~=!
       echo.!str!
       if %%i equ %n% echo !var:~1!&goto end
       )else echo.
)
:end
start notepad "b.txt"&exit