ubuntu restore previous version code example
Example: rollback ubuntu system
$ sudo add-apt-repository "deb http://ppa.launchpad.net/nemh/systemback/ubuntu xenial main"
$ sudo add-apt-repository "deb http://ppa.launchpad.net/nemh/systemback/ubuntu focal fossa main"
1. $ sudo su // su to root user.
2. $ {Enter your password next for the logged in user, you are trying to sudo!)
3. You should be as root user now. From here just drop the "sudo" before any commandline
script and run in the terminal or console without having to enter the password everytime you want to execute code lines.
4. $ add-apt-repository "deb http://ppa.launchpad.net/nemh/systemback/ubuntu xenial main"