Kernel parameters
zh-CN:Kernel parameters There are three ways to pass options to the kernel and thus control its behaviour:
- When building the kernel. See Kernel Compilation for details.
- When starting the kernel (usually, when invoked from a boot loader).
- At runtime (through the files in
/proc
and/sys
). See sysctl for details.
This page now explains in more detail the second method and shows a list of most used kernel parameters in Arch Linux.
Contents
Configuration
Kernel parameters can be set either temporarily by editing the boot menu when it shows up, or by modifying the boot loader's configuration file.
Here we are adding the parameters quiet
and splash
to Syslinux, GRUB, GRUB Legacy, LILO, Gummiboot and rEFInd.
Syslinux
- Press
Tab
when the menu shows up and add them at the end of the string:
linux /boot/vmlinuz-linux root=/dev/sda3 initrd=/boot/initramfs-linux.img quiet splash
- Press
Enter
to boot with these parameters.
- To make the change persistent after reboot, edit
/boot/syslinux/syslinux.cfg
and add them to theAPPEND
line:
APPEND root=/dev/sda3 quiet splash
For more information on configuring Syslinux, see the Syslinux article.
GRUB
- Press
e
when the menu shows up and add them on thelinux
line:
linux /boot/vmlinuz-linux root=UUID=978e3e81-8048-4ae1-8a06-aa727458e8ff quiet splash
- Press
b
to boot with these parameters.
- To make the change persistent after reboot, while you could manually edit
/boot/grub/grub.cfg
with the exact line from above, for beginners it's recommended to:
- Edit
/etc/default/grub
and append your kernel options to theGRUB_CMDLINE_LINUX_DEFAULT
line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
- And then automatically re-generate the
grub.cfg
file with:
# grub-mkconfig -o /boot/grub/grub.cfg
For more information on configuring GRUB, see the GRUB article.
GRUB Legacy
- Press
e
when the menu shows up and add them on thekernel
line:
kernel /boot/vmlinuz-linux root=/dev/sda3 quiet splash
- Press
b
to boot with these parameters.
- To make the change persistent after reboot, edit
/boot/grub/menu.lst
and add them to thekernel
line, exactly like above.
For more information on configuring GRUB Legacy, see the GRUB Legacy article.
LILO
- Add them to
/etc/lilo.conf
:
image=/boot/vmlinuz-linux ... quiet splash
For more information on configuring LILO, see the LILO article.
Gummiboot
- Press
e
when the menu appears and add the parameters to the end of the string:
initrd=\initramfs-linux.img root=/dev/sda2 rw quiet splash
- Press
Enter
to boot with these parameters.
Space
while booting for the Gummiboot menu to appear.- To make the change persistent after reboot, edit
/boot/loader/entries/arch.conf
(assuming you set up your EFI System Partition and configuration files according to the instructions in the Beginners' Guide) and add them to theoptions
line:
options root=/dev/sda2 rw quiet splash
For more information on configuring Gummiboot, see the Gummiboot article.
rEFInd
- To make the change persistent after reboot, edit
/boot/EFI/arch/refind_linux.conf
(ie. refind_linux.conf in the folder your kernel is located in) and append them to all/required lines, for example:
"Boot to X" "root=PARTUUID=978e3e81-8048-4ae1-8a06-aa727458e8ff ro rootfstype=ext4 quiet splash
- If you've disabled auto-detection of OS's in rEFInd and are defining OS stanzas instead in
/boot/EFI/refind/refind.conf
to load your OS's, you can edit it like:
menuentry "Arch" { loader /EFI/arch/vmlinuz-arch.efi options "quiet splash ro root=PARTUUID=978e3e81-8048-4ae1-8a06-aa727458e8ff"
For more information on configuring kernel parameters in rEFInd, see Configuring the rEFInd Bootmanager
Parameter list
Parameters always come in parameter
or parameter=value
. All of these parameters are case-sensitive.
parameter | Description |
---|---|
root= |
Root filesystem. |
ro |
Mount root device read-only on boot. |
rw |
Mount root device read-write on boot (default). |
initrd= |
Specify the location of the initial ramdisk. |
init= |
Run specified binary instead of /sbin/init (symlinked to systemd in Arch) as init process.
|
init=/bin/sh |
Boot to shell. |
systemd.unit= |
|
systemd.unit=multi-user |
Boot to a specified runlevel. |
systemd.unit=rescue |
Boot to single-user mode (root). |
nomodeset |
Disable Kernel Mode Setting. |
For a complete list of all options, please see the kernel documentation.