NixOS development is that much open and avoids such a fragmentation!
Thanks contributors for your work!
How is this feasible?
Install (and name) different overlays for one package.
Can I get 3 variants of one Firefox by applying (plain) overlay1, overlay2, “brocolly_overlay” and be able to simultaneously run 2 browser sessions: Firefox with overlay1 and Firefox with overlay2?
Install 2 stacks of GNOME - 3.10 and 3.12 (NixPills, Chapter 1). What should I use? “nix-env”, “configuration.nix”?
Switch between them without rebuild. How?
Consider installing 4 versions of Opera altogether:
- from nixpkgs: opera-66…
- from nixpkgs-unstable: opera-67…
- from nixpkgs (version is same as in nixpkgs, but with an overlay applied)
- from different repository: opera-68…
How can I run (start) specific version (one of four Opera versions installed)?
- Can I do that, using KDE Plasma menu?
Search for “opera”, get 4 versions of Opera, start one of them.
Search for “opera-66”. Version and overlay usage are not “very much” specified. Therefore, get 2 versions of Opera to choose from: one with an overlay, another without an overlay.
Search for “opera-67.0.3575.31”. Get 1 version of Opera (version is clearly specified).
- Somehow edit “configuration.nix” file …?
Then, enter following in the terminal: “opera”. Opera version specified for a user in the “configuration.nix” as a default should start.
Although, it’s uncommon to encounter multiple versions of a package usually on NixOS Search - Loading..., is that right?
I have found that:
- “nix-env -f nixpkgs-unstable -i (package_name)” installs latest version of a package from nixpkgs-unstable.
- In “configuration.nix”, at least 1 overlay can be configured with:
nixpkgs.overlays = [ … ];