1.6 KiB
Ad-Hoc Package Management
With the command nix-env, you can install and uninstall packages from
the command line. For instance, to install Mozilla Thunderbird:
$ nix-env -iA nixos.thunderbird
If you invoke this as root, the package is installed in the Nix profile
/nix/var/nix/profiles/default and visible to all users of the system;
otherwise, the package ends up in
/nix/var/nix/profiles/per-user/username/profile and is not visible to
other users. The -A flag specifies the package by its attribute name;
without it, the package is installed by matching against its package
name (e.g. thunderbird). The latter is slower because it requires
matching against all available Nix packages, and is ambiguous if there
are multiple matching packages.
Packages come from the NixOS channel. You typically upgrade a package by updating to the latest version of the NixOS channel:
$ nix-channel --update nixos
and then running nix-env -i again. Other packages in the profile are
not affected; this is the crucial difference with the declarative
style of package management, where running nixos-rebuild switch causes
all packages to be updated to their current versions in the NixOS
channel. You can however upgrade all packages for which there is a newer
version by doing:
$ nix-env -u '*'
A package can be uninstalled using the -e flag:
$ nix-env -e thunderbird
Finally, you can roll back an undesirable nix-env action:
$ nix-env --rollback
nix-env has many more flags. For details, see the nix-env(1) manpage or
the Nix manual.