How To: run a program with nix run command:

run a program with `nix run` command:

for FlakeHub, 
0.1# is latest unstable.
0# is latest stable.

```
sudo NIXPKGS_ALLOW_UNFREE=1 nix run --impure "https://flakehub.com/f/NixOS/nixpkgs/=0.1#code-cursor"   
```

for example. or, if you don't need unfree, remove --impure.
