readme: fix sed expression

[DamienCassou]

No description provided.

[Samasaur1]

My guess is that you're using GNU sed as opposed to the BSD sed that comes with macOS. This command works fine with the macOS sed

[Samasaur1]

We could also update the command to be

sed -i'' -e "s/simple/$(scutil --get LocalHostName)/" flake.nix

which works with both BSD and GNU sed

[DamienCassou]

@Samasaur1: I didn't install any version of sed specifically. I'm just switching from linux to os x today and I'm still in the process of installing stuff. Anyway, I changed my commit to follow your suggestion.

[Samasaur1]

You're still missing the -e option

[Samasaur1]

Suggested change

	sed -i'' "s/simple/$(scutil --get LocalHostName)/" flake.nix
	sed -i'' -e "s/simple/$(scutil --get LocalHostName)/" flake.nix

[Enzime]

@DamienCassou I think it's still missing the -e

[emilazy]

-i'' is incorrect for macOS’s default BSD sed. It needs to be -i '' or you get a flake.nix-e file.

[DamienCassou]

I don't see any way to make a command that works in all cases. I am therefore closing the PR. Feel free to reopen if you see a way forward.