Basics

This page records some useful basic concepts and commands for nix

Note

  • Nix store: The approach taken by Nix is different. Nix stores all packages into a common place called the Nix store, usually located at /nix/store. Each package is stored in a unique subdirectory in the store, and each package has its own tree structure

Install nix

nix can be installed using the following command

sh <(curl -L https://nixos.org/nix/install) --daemon

Note

We may need to configure nix accordingly to use all of its features, e.g.,

  • Set the environment variable XDG_CONFIG_HOME, e.g.,
    export XDG_CONFIG_HOME=/home/szhang/.config
  • Edit $XDG_CONFIG_HOME/nix/nix.conf (we may need to create one if it does not exist) and add the line experimental-features = nix-command flakes.
    Note that by doing this we switch on the unstable version of nix, in order to keep using the stable version, we need to specify nixpkg in our future nix command, e.g., nix search nixpkgs emacs instead of nix search emacs

Use nix

Packages

Description

Command

Example

Install a package

nix-env -i <pkg> or nix-env -iA <channel>.<pkg>

nix-env -i hello or nix-env -iA nixpkgs.hello

Remove a package

nix-env -e <pkg>

nix-env -e hello

Upgrade a package

nix-env --upgrade <pkg>

nix-env --upgrade hello

Query installed packages

nix-env --query <pkg>

nix-env --query hello or nix-env --query "*"

Search a package

nix search <channel> <pkg>

nix search nixpkgs hello

Locate a package (within nix shell)

type <pkg>

type hello

Search an excutable

command -v <pkg>

N/A
Channels (all nix channels)

Description

Command

Example

List existing channels

nix-channel --list

N/A

Add a new channel

  • nix-channel --add <channel_link> <channel_name>

  • nix-channel –update

  • nix-channel --add https://nixos.org/channels/nixos-19.03 nixpkgs

  • nix-channel --update

Remove a channel

  • nix-channel --remove <channel_name>

  • nix-channel --update

  • nix-channel --remove https://nixos.org/channels/nixos-19.03 nixpkgs

  • nix-channel --update
Build (see Advanced for more details)

Description

Command

Example

build a package

nix-build '<channel name>' -A <pkg>

nix-build '<nixpkgs>' -A <hello>

clean up nix store (unused packages)

nix-collect-garbage

N/A
Flakes

Description

Command

Example

show the outputs of a flake URL

nix flake show '<URL>'

nix flake show nixpkgs

clone the flake source to a local directory

nix flake clone <URL> -f <local>

nix flake clone git+https://github.com/balsoft/hello-flake/ -f hello-flake

Reference