gistfile1.txt

$ nix-repl 
Welcome to Nix version 1.11.15. Type :? for help.

nix-repl> :l <nixpkgs>
Added 7876 variables.

nix-repl> simple = derivation { name = "simple"; builder = "${bash}/bin/bash"; args = [ ./simple_builder.sh ]; gcc = gcc; coreutils = coreutils; src = ./simple.c; system = builtins.currentSystem; }

nix-repl> :b simple
these derivations will be built:
  /nix/store/dyd9yhalxh55bq2mmr5z3gzp0sm5ngd5-simple.drv
building path(s) ‘/nix/store/ipij0gvkrcc5269izv9qw2a0xkr6g48x-simple’
/nix/store/3pmhqksyv8z241j8rc6m0s6my93vi6bh-simple.c: In function 'main':
/nix/store/3pmhqksyv8z241j8rc6m0s6my93vi6bh-simple.c:2:5: warning: implicit declaration of function 'puts' [-Wimplicit-function-declaration]
     puts("Simple!");
     ^~~~
warning: you did not specify ‘--add-root’; the result might be removed by the garbage collector
/nix/store/ipij0gvkrcc5269izv9qw2a0xkr6g48x-simple

this derivation produced the following outputs:
  out -> /nix/store/ipij0gvkrcc5269izv9qw2a0xkr6g48x-simple

nix-repl> 

[nix-shell:~/projects/nixpkgs]$ /nix/store/ipij0gvkrcc5269izv9qw2a0xkr6g48x-simple/simple 
Simple!