nix-env

Nix-env is a command line tool used in the Nix package manager. It allows users to manage and manipulate the software packages installed on their system. The tool is primarily used for creating, modifying, and deleting user environments, which are isolated collections of software packages. Users can use nix-env to add or remove packages, upgrade or downgrade packages, and create and manage custom environments. The tool provides various options to control package installation and removal, such as specifying package versions, handling dependencies, and managing package sets. Nix-env also supports creating and managing multiple profiles, allowing users to have different sets of packages for different purposes. The tool provides a user-friendly interface, with command line autocompletion and tab completion support for making package management easier. It supports both single-user and multi-user installations, allowing system-wide package management when used with appropriate permissions. Nix-env is highly extensible, allowing users to define custom package sets and configuration options. Overall, nix-env provides a powerful and flexible way to manage packages and environments in the Nix package manager.