Linux Tips

NOTE: Just about all of the tips I'm listing are relevant to Red Hat 8.0 -- it's what I run.

Booting to single-user mode using GRUB

Imagine, if you will, a disgruntled system adminstrator, who, before he or she departs for places unknown, changes the root password on all your Linux systems and "forgets" to inform anyone.  How do you get access to the "root" account to change the "root" password?  I'm sure that you can think of other scenarios where the same need arises.  Here's how you can gain access to the system as "root" without knowing the "root" password:

1. Re-boot the system.
2. When the GRUB boot-loader appears, select the appropriate OS from the list by moving up or down with the arrow keys.
3. Press the 'a' key.  This will allow you to append parameters to the "kernel" command.  You should see something like:
   
   
   • grub append>ro root=LABEL=/
     
     
4. Append the word "single" (without the quotes, making sure to put a space between the slash ("/") and the word "single") so the command looks like:
   
   
   • grub append>ro root=LABEL=/ single
     
     
5. Press the Enter key.

At this point the system should boot to single-user mode and you will have "root" access.  Voila!  You can change the "root" password.

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