# nix > Utilities for the Nix language and store. > More information: . - Search for a package via its name or description: `nix search {{search_term}}` - Start a Nix shell with the specified packages available: `nix run {{nixpkgs.pkg1 nixpkgs.pkg2 nixpkgs.pkg3...}}` - Optimise Nix store disk usage by combining duplicate files: `nix optimise-store` - Start an interactive environment for evaluating Nix expressions: `nix repl` - Upgrade Nix to the latest stable version: `nix upgrade-nix`