The command nixos-rebuild list-generations produces an output in the following format:
Generation Build-date NixOS version Kernel Configuration Revision Specialisation
19 current 2023-12-27 20:38:59 23.11.2217.d02d818f22c7 6.6.8 *
...
...
Is there any documentation what the columns mean?
I do not know what Configuration Revision and Specialisation want to tell me.
Thanks for your help.
Specialisations are basically extra configurations that are built in addition to the default one. The table tells you that you don’t currently use any. Tweag have a nice blog post explaining them in more detail: Introduction to NixOS specialisations
The configuration revision is literally what it says on the tin, the git commit from which the generation was built: NixOS Search
I think you need to set it manually to get a value in there though.
The manpage says:
list-generations [–json]
List the available generations in a similar manner to the boot loader menu. It shows the generation number, build date and time, NixOS version, kernel version and the configuration revision. There is also a json version of output available.
There is literally no documentation about it in the official docs, though, neither in stable nor unstable. It is mentioned on wiki.nixos.org, only. According to release notes on GitHub the command was added in 23.11.