342mb? nix-shell -p nix-info --run "nix-info -m"

End of the installer of nix package manager say to run:
$ nix-shell -p nix-info --run “nix-info -m”

And it gave me:
these 49 paths will be fetched (65.92 MiB download, 342.49 MiB unpacked):

Why is it installing 340mb?
Is that a 1time install for being 1st time running the nix-shell command?

Hello there!

I don’t know why the installer asks you to run the command, but here’s what it does (taken from the manpages):

  • nix-shell: Start an interactive shell based on a Nix expression. A nix-shell will temporarily modify your $PATH environment variable. This can be used to try a piece of software before deciding to permanently install it.
  • -p nix-info option: Set up a temporary environment in which the package nix-info is present and can be used (-p is shorthand for --packages).
  • --run "nix-info -m": executes the command “nix-info -m” in the shell, provided by the nix-info package
  • nix-info -m: shows high level system info (like system architecture, host OS, Nix version)

By the way, don’t worry about the additional 342 MB - they will be removed from the Nix Store the next time you do a nix-collect-garbage.