How I broke my Linux (RHEL) and fixed it

Few months back I moved to RHEL Linux and managed to crash the OS by doing seemingly safe things. Here I am sharing my experience with other users so that they don't end up wasting time like me.

What I did

Installed XFCE and then uninstalled it

Why

I was hoping it to be better than gnome in terms of user experience. Later found its actually minimalistic desktop mainly for low end systems.

What happen

System failed to boot. Failsafe boot option also didn't work.

How I fixed

Reinstalled Gnome desktop by booting to RHEL command

1. Boot to Red Hat command line (steps in 'how to' below)
2. Ensure the network is working (steps in 'how to' below)
3. Reinstall gnome by giving command

              Yum groupinstall “GNOME Desktop Environment”

Should you try it

You can of course try XFCE but if you uninstall make sure to install Gnome Desktop again before any sort of reboot. I haven't tried this but based on my experience this should prevent the OS crash on next reboot.

Below are few ‘how to' which might be useful in case of system crash:

How To 1: How to boot RHEL to command prompt (not the grub menu)

1. Boot/reboot machine

2. At blue Red Hat screen press any key to enter the boot loader

3. Press 'e' to edit the most recent boot command

4. Use the arrow keys to select the line that starts with "kernel"

5. Press 'e' to edit the kernel command

6. Append 'S' to the end of the line. There should be a space before the previous end of the line (probably 'quiet') and the 'S'. Capitalization matters.

7. Hit Enter to commit the change

8. Hit 'b' to boot

9. When it is done booting you will be at a command prompt. Type 'help' for list of available commands

How To 2: How to connect network in the command line mode

Once you get the command line it's of no use if you have to install something and you are not on network. To start network (assuming that whatever you did to crash your system, it didn't mess up your network settings)

dhclient eth0

Note:

1. I am pretty sure that other people might be having similar inputs so feel free to put in the comments.
2. The reason/solutions mentioned are based on my search on internet, in case someone has anything to correct/add, please feel free to point out.