Overview
Kernel parameters can be used to change some kernel settings at boot time. You can change the parameter temporary (only for a single boot) or permanently.
Check Kernel Parameters
To display the current kernel parameter run:
$ cat /proc/cmdline
Temporary Change
These changes are valid only once. If you restart your system, they no longer hold.
Reboot
Open the grub menu at boot
Use „arrow key up“ or „arrow key down“ to stop the countdown
If the grub menu does not appear, press „shift“ several times during booting
Select the desired kernel entry
Press „e“
Edit the line, which starts with
linux. The last words on this line are the kernel parameters.Press „F10“ to boot
For example:
| UI Text Box | ||
|---|---|---|
| ||
menuentry |
...
'Ubuntu, |
...
with |
...
Linux |
...
3.5.0-54-generic |
...
(Writable)' |
...
--class |
...
ubuntu |
...
--class |
...
gnu-linux |
...
--class |
...
gnu |
...
--class |
...
os |
...
{ |
...
|
...
|
...
gzio |
...
|
...
part_msdos |
...
|
...
ext2 |
...
|
...
root='(hd0,msdos1)' |
...
|
...
--no-floppy |
...
--fs-uuid |
...
--set=root |
...
28adfe9d-c122-479a-ab81-de57d16516dc |
...
|
...
root=/dev/mapper/faramir-root |
...
ro |
...
quiet splash |
...
|
...
| UI Text Box | ||
|---|---|---|
| ||
linux /vmlinuz-3.5.0-54-generic |
...
root=/dev/mapper/faramir-root |
...
ro |
...
quiet splash |
The three kernel parameters in this example are ro quiet splash.
Change Kernel Parameters permanently
$ sudo nano /etc/default/grubAdd your parameters to the line:
GRUB_CMDLINE_LINUX_DEFAULT=„quiet splash“(this line may contain different kernel parameters)
It should look like this:
GRUB_CMDLINE_LINUX_DEFAULT=„quiet splash yourParameter=1
$ sudo update-grubreboot the pc
...
Check Kernel Parameters
To display the current kernel parameter run:
...