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--- linux_wiki:modify_the_system_bootloader [2016/03/03 23:12]
billdozor
+++ linux_wiki:modify_the_system_bootloader [2019/05/25 23:50]
@@ Line 1: / Line 1: @@
-====== Modify The System Bootloader ======
-**General Information**
-Managing Grub2; the system boot loader.
-----
-===== Grub2 Structure =====
-**Grub2 files:**
-  * /boot/grub2/grub.cfg => grub2 generated menu (**do not edit directly**)
-  * /etc/default/grub => grub2 variables (can be edited, then menus re-generated)
-  * /etc/grub.d/ => individual files used internally by grub2
-**Grub2 symlinks**
-  * /etc/grub2.cfg => symlink to /boot/grub2/grub.cfg
-  * /etc/sysconfig/grub => symlink to /etc/default/grub
-----
-===== Grub2 Commands =====
-**View the active kernel that is default for system boot**
-<code bash>
-grub2-editenv list
-saved_entry=CentOS Linux (3.10.0-327.3.1.el7.x86_64) 7 (Core)
-</code>
-\\
-**View list of kernels displayed on grub menu**
-<code bash>
-grep ^menuentry /boot/grub2/grub.cfg
-menuentry 'CentOS Linux (3.10.0-327.3.1.el7.x86_64) 7 (Core)' ...
-menuentry 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)' ...
-menuentry 'CentOS Linux (0-rescue-15bdd5425c924660bb6c9979dc071d56) 7 (Core)' ...
-</code>
-\\
-**Set default kernel for grub system boot (permanent)**
-<code bash>
-grub2-set-default 'CentOS Linux (3.10.0-327.3.1.el7.x86_64) 7 (Core)'
-</code>
-  * Note: Copy/paste including the single quotes from the "grep ^menuentry" output
-\\
-**Changing Grub2 settings**
-  - Edit grub2 variables<code bash>vim /etc/default/grub</code>
-  - After making changes, re-generate the grub2 menu<code bash>grub2-mkconfig -o /boot/grub2/grub.cfg</code>
-----