If the user tries to run a program that doesn't exist from Bash, the
program name is looked up in a database that maps to Nix package
names. If it is found, we print out a message like:
$ pdflatex
The program ‘pdflatex’ is currently not installed. It is provided by
several packages. You can install it by typing one of the following:
nix-env -i tetex
nix-env -i texlive-core
If the environment variable $NIX_AUTO_INSTALL is set, the command is
installed and executed automatically:
$ hello --version
The program ‘hello’ is currently not installed. It is provided by
the package ‘hello’, which I will now install for you.
installing `hello-2.8'
hello (GNU hello) 2.8
Copyright (C) 2011 Free Software Foundation, Inc. ...
To use this, you must currently manually put the SQLite programs
database in /var/lib/nixos/programs.sqlite. In the future, this file
should be provided as part of the NixOS channel so it gets updated
automatically. To get a test version:
$ curl http://nixos.org/~eelco/programs.sqlite.xz | xz -d > /var/lib/nixos/programs.sqlite
b89f941b20