How do I view information about a package in nix?

Question

How do I get more details about a nix package, e.g. to verify that it actually is what I think it is.

In Debian, I would use apt-cache show; but how do I get similar information for nix? A command to show the derivation for an arbitrary package would be good enough, since I can probably use the src line to find the website hosting the project.

There is a site for Nix packages and one for NixOS options – wizzup Nov 16 '17 at 11:26 — wizzup, Nov 16 '17 at 11:26

score 11 · Accepted Answer · edited Nov 16 '17 at 17:46

11

Pass the --description flag to nix-env -qa ("query available") for a brief summary, or pass --json (or --xml --meta) for more verbose output, with similar content to that available on Debian; though you'll probably also need something that can wrangle those forms to human readable

# nix-env -qa --description neovim
neovim-0.2.0  Vim text editor fork focused on extensibility and agility
# nix-env -qa --json neovim
{"nixos.neovim":{"name":"neovim-0.2.0","system":"x86_64-linux","meta":{"descriptio...

edited Nov 16 '17 at 17:46

jpaugh

329

answered Nov 15 '17 at 20:56

thrig

34,938

Thanks! I wonder why --description is not the default? I made an edit to emphasize the needed options, since I didn't realize nix-env -qa had an alternate output. – jpaugh Nov 16 '17 at 17:15
1

note: not all packages have descriptions – Knu Jan 11 '19 at 03:52

How do I view information about a package in nix?

1 Answers1