$ git commit hello-flake flake.nix -m 'added bovine feature'
-[main a10700e] added bovine feature
+[main cb77c4d] added bovine feature
2 files changed, 13 insertions(+), 1 deletion(-)
$ nix run
________________________
@@ -3381,7 +3381,7 @@ You can come back to this section later to learn more.
$ nix shell nixpkgs#ghc
-$ runghc Main.hs # Won't work
+$ runghc Main.hs # Fails
Main.hs:1:1: error: [GHC-87110]
Could not find module ‘Network.HostName’.
@@ -3400,7 +3400,7 @@ Let’s exit that shell and try again, this time adding the hostname
$ exit
$ nix shell nixpkgs#ghc nixpkgs#hostname
-$ runghc Main.hs # Won't work
+$ runghc Main.hs # Fails
Main.hs:1:1: error: [GHC-87110]
Could not find module ‘Network.HostName’.
@@ -3423,7 +3423,7 @@ The package we want is in the package set called haskellPackages<
$ exit
$ nix shell nixpkgs#ghc nixpkgs#haskellPackages.hostname
-$ runghc Main.hs # Won't work
+$ runghc Main.hs # Fails
Main.hs:1:1: error: [GHC-87110]
Could not find module ‘Network.HostName’.
@@ -3770,7 +3770,7 @@ warning: creating lock file '"/home/amy/codeberg/nix-book/source/new-flake/haske
• Added input 'haskell-flake':
'github:srid/haskell-flake/2acbf1c9bb7aac38b59dcc3c1bd78911cf37e42c?narHash=sha256-jwZT6Ns4BXlrFHaXjZgZwfhSaw8nTCTKZ8fCDylrONM%3D' (2025-09-14)
• Added input 'nixpkgs':
- 'github:nixos/nixpkgs/6d7ec06d6868ac6d94c371458fc2391ded9ff13d?narHash=sha256-fEvTiU4s9lWgW7mYEU/1QUPirgkn%2BodUBTaindgiziY%3D' (2025-09-13)
+ 'github:nixos/nixpkgs/88cef159e47c0dc56f151593e044453a39a6e547?narHash=sha256-kYhNxLlYyJcUouNRazBufVfBInMWMyF%2B44xG/xar2yE%3D' (2025-09-14)
warning: Git tree '/home/amy/codeberg/nix-book/source/new-flake/haskell-flake/hello-haskell' is dirty
@@ -3788,6 +3788,11 @@ The important thing for now is that the build succeeded.
$ nix run
warning: Git tree '/home/amy/codeberg/nix-book/source/new-flake/haskell-flake/hello-haskell' is dirty
+these 2 derivations will be built:
+ /nix/store/b67dd3m503q30yiwfgav3xzz88bb91h4-hello-flake-haskell-source-1.0.0.drv
+ /nix/store/bgjyjh7282728b2qff37ldygg80zk4m1-hello-flake-haskell-1.0.0.drv
+building '/nix/store/b67dd3m503q30yiwfgav3xzz88bb91h4-hello-flake-haskell-source-1.0.0.drv'...
+building '/nix/store/bgjyjh7282728b2qff37ldygg80zk4m1-hello-flake-haskell-1.0.0.drv'...
Hello from Haskell inside a Nix flake!
Your hostname is: wombat11k
@@ -3807,7 +3812,7 @@ We need to add this to the repo, and commit all important files.
$ git add flake.lock
$ git commit -a -m 'initial commit'
-[master (root-commit) d35f8fd] initial commit
+[master (root-commit) c64c57a] initial commit
5 files changed, 170 insertions(+)
create mode 100644 LICENSE
create mode 100644 Main.hs
@@ -4009,7 +4014,7 @@ First we’ll try building the package manually.
-
$ python -m build # Won't work
+$ python -m build # Fails
/nix/store/iyff8129iampdw13nlfqalzhxy8y1hi9-python3-3.13.6/bin/python: No module named build
@@ -4212,7 +4217,7 @@ something like this.
-
$ nix build # Won't work
+$ nix build # Fails
error: Path 'flake.nix' in the repository "/home/amy/codeberg/nix-book/source/new-flake/python-flake/hello-python" is not tracked by Git.
To make it visible to Nix, run:
@@ -4236,7 +4241,7 @@ warning: creating lock file '"/home/amy/codeberg/nix-book/source/new-flake/pytho
• Added input 'flake-utils/systems':
'github:nix-systems/default/da67096a3b9bf56a91d16901293e51ba5b49a27e?narHash=sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768%3D' (2023-04-09)
• Added input 'nixpkgs':
- 'github:NixOS/nixpkgs/5ad881b15fb2b63c2f127533ca59f840fcc24c3f?narHash=sha256-P8XdKg87fR5PpCjIgMH%2B05PDwhdmlNrigsvChdHfyaw%3D' (2025-09-14)
+ 'github:NixOS/nixpkgs/dd16e0b60390586a261a4e28fc180a91212fe010?narHash=sha256-yM1FFsRiyESij/lzbdBMCUoFOKMoShHu0CAexnBWzTM%3D' (2025-09-15)
warning: Git tree '/home/amy/codeberg/nix-book/source/new-flake/python-flake/hello-python' is dirty
@@ -4254,6 +4259,9 @@ The important thing for now is that the build succeeded.
$ nix run
warning: Git tree '/home/amy/codeberg/nix-book/source/new-flake/python-flake/hello-python' is dirty
+this derivation will be built:
+ /nix/store/kr0aywqsm9v8ds4mc909iaan2yaqmjq3-hello-flake-python.drv
+building '/nix/store/kr0aywqsm9v8ds4mc909iaan2yaqmjq3-hello-flake-python.drv'...
Hello from inside a Python program built with a Nix flake!
@@ -4272,7 +4280,7 @@ We need to add this to the repo, and commit all important files.
$ git add flake.lock
$ git commit -a -m 'initial commit'
-[master (root-commit) 2af9bd5] initial commit
+[master (root-commit) deac9ed] initial commit
4 files changed, 127 insertions(+)
create mode 100644 flake.lock
create mode 100644 flake.nix
@@ -4655,7 +4663,7 @@ sanitized: <strong>some text</strong>