aboutsummaryrefslogtreecommitdiff
path: root/doc/manual/src/command-ref/nix-shell.md
diff options
context:
space:
mode:
authorEelco Dolstra <edolstra@gmail.com>2020-07-31 15:43:25 +0200
committerEelco Dolstra <edolstra@gmail.com>2020-07-31 15:43:25 +0200
commit1d0a7b54fa330b041a720932ee4e05dcad1d2d5c (patch)
tree48627a3530e4d6d58c612864b2e99afb11a0a902 /doc/manual/src/command-ref/nix-shell.md
parent0c94c176446bd9e9cb8c7e16fb7c6d88bb4e9a20 (diff)
Enable syntax highlighting
Diffstat (limited to 'doc/manual/src/command-ref/nix-shell.md')
-rw-r--r--doc/manual/src/command-ref/nix-shell.md142
1 files changed, 85 insertions, 57 deletions
diff --git a/doc/manual/src/command-ref/nix-shell.md b/doc/manual/src/command-ref/nix-shell.md
index 492351867..27826717b 100644
--- a/doc/manual/src/command-ref/nix-shell.md
+++ b/doc/manual/src/command-ref/nix-shell.md
@@ -39,10 +39,12 @@ after `$stdenv/setup` has been sourced. Since this hook is not executed
by regular Nix builds, it allows you to perform initialisation specific
to `nix-shell`. For example, the derivation attribute
- shellHook =
- ''
- echo "Hello shell"
- '';
+```nix
+shellHook =
+ ''
+ echo "Hello shell"
+ '';
+```
will cause `nix-shell` to print `Hello shell`.
@@ -108,46 +110,58 @@ The following common options are supported:
To build the dependencies of the package Pan, and start an interactive
shell in which to build it:
- $ nix-shell '<nixpkgs>' -A pan
- [nix-shell]$ unpackPhase
- [nix-shell]$ cd pan-*
- [nix-shell]$ configurePhase
- [nix-shell]$ buildPhase
- [nix-shell]$ ./pan/gui/pan
+```shell
+$ nix-shell '<nixpkgs>' -A pan
+[nix-shell]$ unpackPhase
+[nix-shell]$ cd pan-*
+[nix-shell]$ configurePhase
+[nix-shell]$ buildPhase
+[nix-shell]$ ./pan/gui/pan
+```
To clear the environment first, and do some additional automatic
initialisation of the interactive shell:
- $ nix-shell '<nixpkgs>' -A pan --pure \
- --command 'export NIX_DEBUG=1; export NIX_CORES=8; return'
+```shell
+$ nix-shell '<nixpkgs>' -A pan --pure \
+ --command 'export NIX_DEBUG=1; export NIX_CORES=8; return'
+```
Nix expressions can also be given on the command line using the `-E` and
`-p` flags. For instance, the following starts a shell containing the
packages `sqlite` and `libX11`:
- $ nix-shell -E 'with import <nixpkgs> { }; runCommand "dummy" { buildInputs = [ sqlite xorg.libX11 ]; } ""'
+```shell
+$ nix-shell -E 'with import <nixpkgs> { }; runCommand "dummy" { buildInputs = [ sqlite xorg.libX11 ]; } ""'
+```
A shorter way to do the same is:
- $ nix-shell -p sqlite xorg.libX11
- [nix-shell]$ echo $NIX_LDFLAGS
- … -L/nix/store/j1zg5v…-sqlite-3.8.0.2/lib -L/nix/store/0gmcz9…-libX11-1.6.1/lib …
+```shell
+$ nix-shell -p sqlite xorg.libX11
+[nix-shell]$ echo $NIX_LDFLAGS
+… -L/nix/store/j1zg5v…-sqlite-3.8.0.2/lib -L/nix/store/0gmcz9…-libX11-1.6.1/lib …
+```
Note that `-p` accepts multiple full nix expressions that are valid in
the `buildInputs = [ ... ]` shown above, not only package names. So the
following is also legal:
- $ nix-shell -p sqlite 'git.override { withManual = false; }'
+```shell
+$ nix-shell -p sqlite 'git.override { withManual = false; }'
+```
The `-p` flag looks up Nixpkgs in the Nix search path. You can override
it by passing `-I` or setting `NIX_PATH`. For example, the following
gives you a shell containing the Pan package from a specific revision of
Nixpkgs:
- $ nix-shell -p pan -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/8a3eea054838b55aca962c3fbde9c83c102b8bf2.tar.gz
+```shell
+$ nix-shell -p pan -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/8a3eea054838b55aca962c3fbde9c83c102b8bf2.tar.gz
- [nix-shell:~]$ pan --version
- Pan 0.139
+[nix-shell:~]$ pan --version
+Pan 0.139
+```
# Use as a `#!`-interpreter
@@ -155,8 +169,10 @@ You can use `nix-shell` as a script interpreter to allow scripts written
in arbitrary languages to obtain their own dependencies via Nix. This is
done by starting the script with the following lines:
- #! /usr/bin/env nix-shell
- #! nix-shell -i real-interpreter -p packages
+```bash
+#! /usr/bin/env nix-shell
+#! nix-shell -i real-interpreter -p packages
+```
where *real-interpreter* is the “real” script interpreter that will be
invoked by `nix-shell` after it has obtained the dependencies and
@@ -170,39 +186,45 @@ because many operating systems only allow one argument in `#!` lines.
For example, here is a Python script that depends on Python and the
`prettytable` package:
- #! /usr/bin/env nix-shell
- #! nix-shell -i python -p python pythonPackages.prettytable
+```python
+#! /usr/bin/env nix-shell
+#! nix-shell -i python -p python pythonPackages.prettytable
- import prettytable
+import prettytable
- # Print a simple table.
- t = prettytable.PrettyTable(["N", "N^2"])
- for n in range(1, 10): t.add_row([n, n * n])
- print t
+# Print a simple table.
+t = prettytable.PrettyTable(["N", "N^2"])
+for n in range(1, 10): t.add_row([n, n * n])
+print t
+```
Similarly, the following is a Perl script that specifies that it
requires Perl and the `HTML::TokeParser::Simple` and `LWP` packages:
- #! /usr/bin/env nix-shell
- #! nix-shell -i perl -p perl perlPackages.HTMLTokeParserSimple perlPackages.LWP
+```perl
+#! /usr/bin/env nix-shell
+#! nix-shell -i perl -p perl perlPackages.HTMLTokeParserSimple perlPackages.LWP
- use HTML::TokeParser::Simple;
+use HTML::TokeParser::Simple;
- # Fetch nixos.org and print all hrefs.
- my $p = HTML::TokeParser::Simple->new(url => 'http://nixos.org/');
+# Fetch nixos.org and print all hrefs.
+my $p = HTML::TokeParser::Simple->new(url => 'http://nixos.org/');
- while (my $token = $p->get_tag("a")) {
- my $href = $token->get_attr("href");
- print "$href\n" if $href;
- }
+while (my $token = $p->get_tag("a")) {
+ my $href = $token->get_attr("href");
+ print "$href\n" if $href;
+}
+```
Sometimes you need to pass a simple Nix expression to customize a
package like Terraform:
- #! /usr/bin/env nix-shell
- #! nix-shell -i bash -p "terraform.withPlugins (plugins: [ plugins.openstack ])"
+```bash
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p "terraform.withPlugins (plugins: [ plugins.openstack ])"
- terraform apply
+terraform apply
+```
> **Note**
>
@@ -213,20 +235,22 @@ Finally, using the merging of multiple nix-shell shebangs the following
Haskell script uses a specific branch of Nixpkgs/NixOS (the 18.03 stable
branch):
- #! /usr/bin/env nix-shell
- #! nix-shell -i runghc -p "haskellPackages.ghcWithPackages (ps: [ps.HTTP ps.tagsoup])"
- #! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/nixos-18.03.tar.gz
+```haskell
+#! /usr/bin/env nix-shell
+#! nix-shell -i runghc -p "haskellPackages.ghcWithPackages (ps: [ps.HTTP ps.tagsoup])"
+#! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/nixos-18.03.tar.gz
- import Network.HTTP
- import Text.HTML.TagSoup
+import Network.HTTP
+import Text.HTML.TagSoup
- -- Fetch nixos.org and print all hrefs.
- main = do
- resp <- Network.HTTP.simpleHTTP (getRequest "http://nixos.org/")
- body <- getResponseBody resp
- let tags = filter (isTagOpenName "a") $ parseTags body
- let tags' = map (fromAttrib "href") tags
- mapM_ putStrLn $ filter (/= "") tags'
+-- Fetch nixos.org and print all hrefs.
+main = do
+ resp <- Network.HTTP.simpleHTTP (getRequest "http://nixos.org/")
+ body <- getResponseBody resp
+ let tags = filter (isTagOpenName "a") $ parseTags body
+ let tags' = map (fromAttrib "href") tags
+ mapM_ putStrLn $ filter (/= "") tags'
+```
If you want to be even more precise, you can specify a specific revision
of Nixpkgs:
@@ -237,12 +261,16 @@ The examples above all used `-p` to get dependencies from Nixpkgs. You
can also use a Nix expression to build your own dependencies. For
example, the Python example could have been written as:
- #! /usr/bin/env nix-shell
- #! nix-shell deps.nix -i python
+```python
+#! /usr/bin/env nix-shell
+#! nix-shell deps.nix -i python
+```
where the file `deps.nix` in the same directory as the `#!`-script
contains:
- with import <nixpkgs> {};
+```nix
+with import <nixpkgs> {};
- runCommand "dummy" { buildInputs = [ python pythonPackages.prettytable ]; } ""
+runCommand "dummy" { buildInputs = [ python pythonPackages.prettytable ]; } ""
+```