bat命令以概率50%選中

setlocal enabledelayedexpansion
SET /p filename=請輸入文件名:
SET num=0
for /f "tokens=*" %%a in (%filename%.txt) do (
SET /a num=!RANDOM!%%100+1
if !num! LEQ 50 (
echo %%a>>out.txt
)
)
endlocal
pause