Quick Start

This chapter is for impatient people who don't like reading documentation. For more in-depth information you are kindly referred to subsequent chapters.

Install single-user Nix by running the following:
```
$ bash <(curl -L https://nixos.org/nix/install)
```
This will install Nix in /nix. The install script will create /nix using sudo, so make sure you have sufficient rights. (For other installation methods, see here.)

See what installable packages are currently available in the channel:

$ nix-env -qaP
nixpkgs.docbook_xml_dtd_43                    docbook-xml-4.3
nixpkgs.docbook_xml_dtd_45                    docbook-xml-4.5
nixpkgs.firefox                               firefox-33.0.2
nixpkgs.hello                                 hello-2.9
nixpkgs.libxslt                               libxslt-1.1.28
…

Install some packages from the channel:
```
$ nix-env -iA nixpkgs.hello
```
This should download pre-built packages; it should not build them locally (if it does, something went wrong).

Test that they work:

$ which hello
/home/eelco/.nix-profile/bin/hello
$ hello
Hello, world!

Uninstall a package:
```
$ nix-env -e hello
```
You can also test a package without installing it:
```
$ nix-shell -p hello
```
This builds or downloads GNU Hello and its dependencies, then drops you into a Bash shell where the hello command is present, all without affecting your normal environment:
```
[nix-shell:~]$ hello
Hello, world!

[nix-shell:~]$ exit

$ hello
hello: command not found
```
To keep up-to-date with the channel, do:
```
$ nix-channel --update nixpkgs
$ nix-env -u '*'
```
The latter command will upgrade each installed package for which there is a “newer” version (as determined by comparing the version numbers).
If you're unhappy with the result of a nix-env action (e.g., an upgraded package turned out not to work properly), you can go back:
```
$ nix-env --rollback
```
You should periodically run the Nix garbage collector to get rid of unused packages, since uninstalls or upgrades don't actually delete them:
```
$ nix-collect-garbage -d
```