show new output for :b

[mhwombat]

The output from the current version of :b in the nix repl shows less information, so when the first derivation is built, the environment isn't printed to the screen. As a result, the purpose of putting declare -xp into the builder script is no longer clear.

Therefore, I split the example into two parts 1) using a builder script that simply echoes "foo" to $out, and 2) a builder script that writes the environment to $out. I think this makes it easier for the user to follow the steps.

[jonringer]

this does a little more than update the :b command, are you sure that you included the right changes?

[mhwombat]

this does a little more than update the :b command, are you sure that you included the right changes?

Yes. In the existing version, when derivation is built, the environment isn't printed to the screen. As a result, the purpose of putting declare -xp into the builder script is no longer clear. That's why I split it into two steps.