在El Capitan和同事的High Sierra(标准终端)中进行了测试(打击)。 user@hostname ~ $ man ls | grep "BU" BUGS user@hostname ~ $ man ls | grep "BUG" user@hostname ~ $ user@hostname ~ $ man ls | grep "IEEE" files in order to be compatible with the IEEE Std 1003.2 (``POSIX.2'') The ls utility conforms to IEEE Std …