Package Management

NixOS provides a set of tools for building, installing, and managing packages.

Verified Usage

nix-build

nix-build builds Nix derivations and produces outputs in the Nix store. It is the preferred way to build software reproducibly.

# Step 1: Create a clean workspace
rm -rf /tmp/nix-hello-c && mkdir -p /tmp/nix-hello-c && cd /tmp/nix-hello-c

# Step 2: Write a C program
cat > hello.c <<'EOF'
#include <stdio.h>

int main(void) {
    puts("Hello, World!");
    return 0;
}
EOF

# Step 3: Write a default.nix
cat > default.nix <<'EOF'
{ pkgs ? import <nixpkgs> {} }:

pkgs.stdenv.mkDerivation {
  pname = "hello-c";
  version = "0.1.0";
  src = ./.;

  dontConfigure = true;

  buildPhase = ''
    cc hello.c -o hello
  '';

  installPhase = ''
    mkdir -p $out/bin
    install -m755 hello $out/bin/hello
  '';
}
EOF

# Step 4: Build and run
nix-build
./result/bin/hello

nix-env

nix-env installs or removes individual packages in your user profile.

# Install the `hello` package
nix-env -iA nixos.hello

# Remove the `hello` package
nix-env -e hello

nix-shell

nix-shell creates a temporary development environment with the specified dependencies. This is useful for testing software without modifying your system environment.

# Enter a shell with the `hello` package available
nix-shell -p hello

nixos-rebuild

nixos-rebuild manages the entire system configuration declaratively. It applies changes defined in configuration.nix, and is the recommended approach for installing packages system-wide.

# Edit the system configuration file
vim /etc/nixos/configuration.nix

# Apply configuration changes and rebuild the system without rebooting
nixos-rebuild test