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So I created that directory and there's a new error:

```
❯ nix-shell -p nodejs-20_x
error: creating directory '/nix/store/.links': Permission denied
```

Created that directory, and there's another error:

```
❯ nix-shell -p nodejs-20_x
error: creating directory '/nix/var/nix/temproots': Permission denied
```

#Nix has an missed opportunity to here to check for these error states and produce a more useful diagnostic message than "permission denied".