内容一：增加 GRUB2 参数
# grubby --update-kernel ALL --add-args "selinux=0 enforcing=0"（补充：这里以增加 selinux=0 enforcing=0 参数为例）
内容二：删除 GRUB2 参数
# grubby --update-kernel ALL --remove-args "selinux=0 enforcing=0"（补充：这里以取消 selinux=0 enforcing=0 参数为例）
内容三：显示 GRUB2 的参数
3.1 显示 GRUB2 参数的简单信息
# grub2-editenv - list | grep kernelopts
kernelopts=root=UUID=ac2abk4hi-5529-26c1-b6o9-365260e054242 ro barrier=off crashkernel=auto rhgb quiet（补充：其实就是 /etc/default/grub 文件中 GRUB_CMDLINE_LINUX=”” 这一行里的参数）
3.2 显示 GRUB2 参数的详细信息
# grubby --info DEFAULT
index=0
kernel="/boot/vmlinuz-5.14.0-687.12.1.el9_8.x86_64"
args="ro barrier=off crashkernel=1G-2G:192M,2G-64G:256M,64G-:512M $tuned_params"
root="UUID=ac2abk4hi-5529-26c1-b6o9-365260e054242"
initrd="/boot/initramfs-5.14.0-687.12.1.el9_8.x86_64.img $tuned_initrd"
title="Red Hat Enterprise Linux (5.14.0-687.12.1.el9_8.x86_64) 9.8 (Plow)"
id="e5b27xh36j583kj7231667u51l5c82hc-5.14.0-687.12.1.el9_8.x86_64"3.3 显示所有历史 GRUB2 参数的详细信息
# grubby --info DEFAULT
index=0
kernel="/boot/vmlinuz-5.14.0-687.12.1.el9_8.x86_64"
args="ro barrier=off selinux=0 crashkernel=1G-2G:192M,2G-64G:256M,64G-:512M $tuned_params"
root="UUID=ac2abk4hi-5529-26c1-b6o9-365260e054242"
initrd="/boot/initramfs-5.14.0-687.12.1.el9_8.x86_64.img $tuned_initrd"
title="Red Hat Enterprise Linux (5.14.0-687.12.1.el9_8.x86_64) 9.8 (Plow)"
id="e5b27xh36j583kj7231667u51l5c82hc-5.14.0-687.12.1.el9_8.x86_64"
index=0
kernel="/boot/vmlinuz-5.14.0-687.12.1.el9_8.x86_64"
args="ro barrier=off selinux=0 crashkernel=1G-2G:192M,2G-64G:256M,64G-:512M $tuned_params"
root="UUID=ac2abk4hi-5529-26c1-b6o9-365260e054242"
initrd="/boot/initramfs-5.14.0-687.12.1.el9_8.x86_64.img $tuned_initrd"
title="Red Hat Enterprise Linux (5.14.0-687.12.1.el9_8.x86_64) 9.8 (Plow)"
id="e5b27xh36j583kj7231667u51l5c82hc-5.14.0-687.10.1.el9_8.x86_64"