guix-package:tldr:2b1d7

The command "guix package --roll-back" is used in the Guix package manager to revert or roll back to a previous generation of packages.

In Guix, each time you install or upgrade packages, a new generation (or version) of your package set is created. These generations are immutable and preserved, allowing you to easily switch between different sets of installed packages.

When you run "guix package --roll-back", Guix will display a list of previous generations of packages along with some information about them, such as the date they were created and the number of installed packages at that time. You can then choose a specific generation by its number to roll back to.

Once you select a generation, Guix will perform the necessary steps to switch your whole system to that generation. This includes downgrading/upgrading packages, installing/removing packages as needed, and updating system configuration files. After the roll-back operation is complete, your system will have the package set identical to the selected generation.

Rolling back can be useful in situations where a package update introduces problems or conflicts. By going back to a previous generation of packages, you can restore the previous stable state of your system.

It's important to note that rolling back affects the entire system, not just individual packages. So any changes made to system configuration files or shared dependencies will also be reverted.