How to back up my entire system?

FILES

Refer to this howto: http://ubuntuforums.org/showthread.php?t=35087

In simple terms, the backup command is: sudo tar czf /backup.tar.gz --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 /backup.tar.gz, 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 /path/to/drive/with/backup.tar.gz -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.

Noone noticed clonezilla. It makes a complete image of your hard drive, so it backups absolutely everything. It's as easy as burning an iso or creating a bootable flash drive.

The actual backup takes a while, but is the most reliable.

To clone your system to another system. Or make a backup. In terminal type:

dpkg --get-selections | grep -v deinstall > ubuntu-files

This command makes a file list of all installed packages in your system (and stores it in present working directory). Backup this file in hdd, email, etc...(this file is very small).

In the freshly installed ubuntu system run:

sudo dpkg --set-selections <./ubuntu-files (will set it up and)

apt-get -y update
apt-get dselect-upgrade

This will install only those packages you had installed (with apt-get) in the old system.

                                    (OR)

You could back up all the .deb packages from /var/cache/apt/archives/ and install them manually using:

dpkg -i *.deb

And after that running an update cycle later.