root@BJ-CentOS7 ~ # uname -sr
root@BJ-CentOS7 ~ # grub2-editenv list
root@BJ-CentOS7 ~ # cat /boot/grub2/grub.cfg |grep ^menuentry 或 rpm -qa kernel
root@BJ-CentOS7 ~ # grub2-set-default 'CentOS Linux (3.10.0-1062.9.1.el7.x86_64) 7 (Core)'