[LINUX] How to use Nix package manager

Nix is good

I use Windows (company-supplied) for work, MacBook Pro (given by a friend) for everyday use, and Manjaro Linux (given by a senior company) for experimentation, all of which are package managers. I'm using nix. (However, Windows uses Nix in Ubuntu on WSL2)

The reason why I use Nix instead of using apt or homebrew quietly is

Easy to reproduce environment because environment can be managed declaratively
Highly customizable
No need for docker
No dust remains in unexpected places when uninstalling
The environment can be restored at any time

I'm happy about that.

I want Nix to become more popular, so I'll show you how to install the Nix package manager and how to use basic commands.

Nix installation

Linux

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

One caveat is that you can't run it with a fish shell.

macOS

$ sh <(curl -L https://nixos.org/nix/install) --darwin-use-unencrypted-nix-store-volume

Addendum to .bashrc

In ~ / .bashrc to set the necessary environment variables to use nix on both Linux and Mac

if [ -e $HOME/.nix-profile/etc/profile.d/nix.sh ]; then
    . $HOME/.nix-profile/etc/profile.d/nix.sh;
fi

Let's add.

Channel registration

First, you need to subscribe to a Unix package channel to use it. Use the nix-channel command to manipulate channels.

$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable
$ nix-channel --update

nix-channel --update is like sudo apt update.

Package management

The main command for package management is nix-env. You can use nix-env to install, upgrade, remove, search for packages, and more.

Search

You can browse all installable packages with nix-env -qa. The same is true for nix-env --query --available.

$ nix-env -qa
aterm-2.2
bash-3.0
binutils-2.15
bison-1.875d
blackdown-1.4.2
bzip2-1.0.2
...

You can search for a specific package by putting the name of the package after -qa.

$ nix-env -qa firefox
firefox-68.11.0esr
firefox-78.1.0esr
firefox-79.0

You can also use regular expressions to search.

$ nix-env -qa 'firefox-.*'

Package installation

You can install the package with nix-env -i or nix-env --install.

By the way, you don't need sudo. Installed packages are installed by the user, not the system. There is (probably) no impact on the entire system.

$ nix-env -i subversion

You can check all installed packages with nix-env -q.

$ nix-env -q
nix-2.3.7
subversion-1.12.2

upgrade

You can update your environment with nix-env -u or nix-env --upgrade.

When upgrading only a specific package,

$ nix-env -u subversion

When upgrading all installed packages,

$ nix-env -u

Uninstall

You can uninstall the package with nix-env -e or nix-env --erase.

nix-env -e subversion
uninstalling 'subversion-1.12.2'

rollback

Nix creates a generation for your environment each time you add or remove a package. And you can roll back to those generations at any time.

For example, it is useful when you have installed a package and had a bug and want to revert to a working installation.

Check generations nix-env --list-generations

$ nix-env --list-generations
   1   2020-08-03 23:36:12   
   2   2020-08-06 19:15:43   
   3   2020-08-06 19:55:13   
   4   2020-08-09 18:33:59   
   5   2020-08-09 18:34:46   (current)

(current) is the current environment.

Use nix-env --rollback to return to the previous environment.

$ nix-env --rollback
switching from generation 5 to 4

$ nix-env --list-generations
   1   2020-08-03 23:36:12   
   2   2020-08-06 19:15:43   
   3   2020-08-06 19:55:13   
   4   2020-08-09 18:33:59   (current)
   5   2020-08-09 18:34:46

To move to a specific generation, use nix-env --switch-generation.

$ nix-env --switch-generation 2
switching from generation 4 to 2