I have made some modifications to my RHEL/Fedora/CentOS, Debian/Ubuntu operating system and now it does not restart. How can I make a recovery / rescue operation?
There are 2 ways to make a rescue system operation: the first is using the rescue cd or live cd distribution you are using, you can also use Knoppix or Puppy Linux; the second, which we will discuss in this post, is passing to the kernel from GRUB, then runlevel which the operating system should be started. To do this:
Restart the computer
Press Esc to enter GRUB
After having entered GRUB, press: a
For RHEL/CentOS add: init 1
For Fedora add only: 1
In Ubuntu you must select the version of the kernel: recovery mode
From there the system starts in mode text, single-user and no start network services, neither web server, mail, DNS, etc., mounted existing partitions existing to create an environment to carry out rescue operations
Make changes to the configuration of the system
Restart