echo %date:~-4,4%%date:~-10,2%%date:~-7,2%_%time:~0,2%%time:~3,2%%time:~6,2%-OUTPUT.txt
Would return (example):
20171409_152203-OUTPUT.txt
echo %date:~-4,4%%date:~-10,2%%date:~-7,2%_%time:~0,2%%time:~3,2%%time:~6,2%-OUTPUT.txt
Would return (example):
20171409_152203-OUTPUT.txt