GRUB (Grand Unified Bootloader) is a bootloader that is commonly used in Linux systems to manage the boot process. It is responsible for loading the Linux kernel and initial RAM disk (initrd) and passing control to the kernel. GRUB allows users to pass various boot options to the kernel during the boot process. These options can be used to configure the kernel, change the behavior of the system, or troubleshoot issues.
Here are some examples of commonly used GRUB boot options:
- “nomodeset”: This option is used to prevent the kernel from setting certain kernel mode setting (KMS) options. KMS options are used to configure the graphics mode for the system. By default, KMS options are set by the kernel during the boot process, but in some cases, these options may cause issues with the system’s display or graphics capabilities.
- “quiet” and “quiet splash”: These options will suppress boot messages and display a graphical splash screen instead.
- “single”: This option will boot the system into single-user mode, which is a minimal environment used for system maintenance and recovery.
- “init=/bin/bash”: This option will launch the system into a bash shell instead of the normal init process. This can be useful for troubleshooting or recovery.
- “debug”: This option will enable debugging during the boot process, and will print more verbose messages to the console.
- “acpi=off”: This option will disable the Advanced Configuration and Power Interface (ACPI), which can be useful for troubleshooting power management issues.
- “noapic”: This option will disable the Advanced Programmable Interrupt Controller (APIC), which can be useful for troubleshooting hardware interrupt issues.
- “nolapic”: This option will disable the local APIC, which can be useful for troubleshooting multi-processor systems.
- “noirqbalance”: This option will disable irqbalance service. It is a daemon that distributes hardware interrupts across multiple processors in a symmetric multiprocessing (SMP) system.
- “mem=xxxx” : This option can be used to specify the amount of memory to be used by the kernel during boot.
- “root=xxxx” : This option can be used to specify the root file system for the kernel.
Please note that not all boot options will be applicable to all systems, and some options may be specific to certain hardware or software configurations.
These are some of the commonly used boot options, but there are many other options available, depending on the specific configuration of the system, and the version of the kernel. It is always recommended to consult the documentation of your distribution and the kernel version you are using to know the exact options and parameters.