How do I change redhat kernel command line parameters for all boot entries?

vaquitasos

This example shows changing the kernel logging.

Initial check of the kernel logging.

$ sysctl kernel.printk
kernel.printk = 7       4       1       7

Edit the file /etc/default/grub make changes to the GRUB_CMDLINE_LINUX variable.

For this example "quite" was added to the end of the line.

GRUB_CMDLINE_LINUX="console=ttyS0,115200n8 console=tty0 net.ifnames=0 rd.blacklist=nouveau crashkernel=auto quiet"

Update the GRUB2 configuration file.

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
done

Reboot when safe to do so.

Check the status of kernel logging after reboot.

$ sysctl kernel.printk
kernel.printk = 4       4       1       7