grub2-mkconfig

ماذا يفعل

طريقة الكتابة

grub2-mkconfig [-o FILE] [--update-bls-cmdline]

الأجزاء الرئيسية

GRUB_TIMEOUT

Seconds the menu waits.

GRUB_DEFAULT

Default entry (saved = use grubenv).

GRUB_CMDLINE_LINUX

Kernel arguments for all kernels.

GRUB_TERMINAL_OUTPUT

console, serial, gfxterm.

GRUB_DISABLE_RECOVERY

No rescue entries.

GRUB_ENABLE_BLSCFG

Use BLS entries (true on RHEL).

الأكثر استخدامًا

لا يوجد شيء يطابق هذا الفلتر.

$ مستخدم عادي# بصلاحية root (أو مع sudo)

1. 1Regenerate after a change

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

   After every edit of /etc/default/grub.

2. 2Change the timeout

   #sed -i 's/^GRUB_TIMEOUT=.*/GRUB_TIMEOUT=10/' /etc/default/grub
   #grub2-mkconfig -o /boot/grub2/grub.cfg

   Menu waits 10 seconds.

3. 3Change kernel arguments for all kernels

   #vim /etc/default/grub
   #grub2-mkconfig -o /boot/grub2/grub.cfg --update-bls-cmdline

   Without the option the existing entries keep their old arguments.

4. 4Preview without writing

   #grub2-mkconfig | less

   Check before you overwrite.

5. 5Back up the old config

   #cp -a /boot/grub2/grub.cfg /root/grub.cfg.bak

   Easy way back.

6. 6Show the menu on a serial console

   #grep -E 'GRUB_TERMINAL|GRUB_SERIAL' /etc/default/grub

   For VMs without a screen.

7. 7Password for the GRUB menu (security)

   #grub2-setpassword

   Nobody can edit boot entries at the console without it (stops rd.break tricks).

8. 8Where is the config on UEFI?

   #cat /boot/efi/EFI/redhat/grub.cfg

   A small stub that loads /boot/grub2/grub.cfg.

9. 9Boot an entry once

   #grub2-reboot 1; reboot

   Only the next boot uses entry 1.

10. 10Check the BLS entries afterwards

    #grep options /boot/loader/entries/*.conf

    The kernel arguments per entry.

لا يوجد شيء يطابق هذا الفلتر.

الملفات

/etc/default/grub

Your settings.

/etc/grub.d/

Scripts that build the config.

/boot/grub2/grub.cfg

Generated config.

/boot/loader/entries/

BLS entries.

رموز الخروج