bd09ef9c21
"Ejecting" from the Finder ejects the entire device which is then not available for dd. diskutil unmountDisk does the right thing. Furthermore writing to diskN instead of rdiskN failed to complete even after waiting >10 minutes.
To build the manual, you need Nix installed on your system (no need
for NixOS). To install Nix, follow the instructions at
https://nixos.org/nix/download.html
When you have Nix on your system, in the root directory of the project
(i.e., `nixpkgs`), run:
nix-build nixos/release.nix -A manual.x86_64-linux
When this command successfully finishes, it will tell you where the
manual got generated.