backup system
December 28, 2019
10:07 AM
81
FILES
Refer to this howto: [link]  
In simple terms, the backup command is: sudo tar czf [file] --exclude=/backup.tar.gz --exclude=/dev --exclude=/mnt --exclude=/proc --exclude=/sys --exclude=/tmp --exclude=/lost+found /. Add more --exclude= parameters if you need to.
It will create an archive of all your files at [file], which you can then copy over to another computer/drive and restore your files if the install goes pear-shaped. You can do it from a LiveCD, by mounting the "bad" system under /media or /mnt and running tar xf [file] -C /mnt (substitute for the actual path to the "bad" system).
GRUB
This will not cover GRUB, however you can easily reinstall it by following this guide here. You only need to do steps Three and Four.
tar cvpzf [file] --exclude=/proc --exclude=/lost+found --exclude=/backup.tgz --exclude=/mnt --exclude=/sys /