Boot Linux Grub Into Single User Mode

To boot Linux into single user mode from the GRUB boot menu, follow these steps:

1. At the GRUB boot menu, use the arrow keys to select the Linux kernel that you want to boot.
2. Press the "e" key to edit the kernel command line.
3. Use the arrow keys to navigate to the line that starts with "linux" or "linux16" and add "single" to the end of the line. For example:

linux /vmlinuz-5.4.0-72-generic root=UUID=e02bce91-52d8-4b17-aab7-2d066b8c8b72 ro single

4. Press "Ctrl+x" or "F10" to boot the kernel with the modified command line.

This will boot the Linux system into single user mode, where you will be logged in as the root user. You can then perform maintenance tasks, such as running filesystem checks or modifying system configuration files.

Note: Be very careful when performing maintenance tasks as the root user, as you have the ability to make changes that could potentially cause serious problems with your system.