nix-super/doc/manual/src/quick-start.md
Jan Tojnar ca4d8ce9e2 doc: De-emphasize nix-env without -A
The manual uses `nix-env -i` without `-A` prominently, teaching a bad practice to newcomers.
2021-11-17 17:04:25 +01:00

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# 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.
1. Install single-user Nix by running the following:
```console
$ 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](installation/installation.md).)
1. See what installable packages are currently available in the
channel:
```console
$ 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
```
1. Install some packages from the channel:
```console
$ nix-env -iA nixpkgs.hello
```
This should download pre-built packages; it should not build them
locally (if it does, something went wrong).
1. Test that they work:
```console
$ which hello
/home/eelco/.nix-profile/bin/hello
$ hello
Hello, world!
```
1. Uninstall a package:
```console
$ nix-env -e hello
```
1. You can also test a package without installing it:
```console
$ 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:
```console
[nix-shell:~]$ hello
Hello, world!
[nix-shell:~]$ exit
$ hello
hello: command not found
```
1. To keep up-to-date with the channel, do:
```console
$ 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).
1. 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:
```console
$ nix-env --rollback
```
1. You should periodically run the Nix garbage collector to get rid of
unused packages, since uninstalls or upgrades don't actually delete
them:
```console
$ nix-collect-garbage -d
```