How to boot into single user mode of CentOS 7.* to edit some file when you forget root’s password

When you forget the password of root using the CentOS 7.*, there is a way to get in the system in the “single user mode”.

Here are steps:

• As the system boots, press Esc to bring up the GRUB boot prompt.
• At the GRUB boot prompt, press E to edit the first boot option.
• Find the kernel line starting with linux16, Change ro to rw init=/sysroot/bin/sh.
• Press Ctrl+X or F10 to boot into single user mode.
• Access the system with the command: chroot /sysroot.
• Do anything you like.
• Run exit to exit sysroot.
• Run reboot -f to reboot the server.