Update `docs/getting_started/permissions.md`
Aligned the example wording more closely with that in the
`first_steps.md` document, and made other minor edits/corrections.
### Permissions whitelist
-Deno also provides permissions whitelist.
+Deno also allows you to control the granularity of permissions with whitelists.
-This is an example to restrict file system access by whitelist.
+This example restricts file system access by whitelisting only the `/usr`
+directory:
```shell
$ deno run --allow-read=/usr https://deno.land/std/examples/cat.ts /etc/passwd
@@ -18,15 +19,15 @@ error: Uncaught PermissionDenied: read access to "/etc/passwd", run again with t
...
```
-You can grant read permission under `/etc` dir
+Try it out again with the correct permissions by whitelisting `/etc` instead:
```shell
$ deno run --allow-read=/etc https://deno.land/std/examples/cat.ts /etc/passwd
```
-`--allow-write` works same as `--allow-read`.
+`--allow-write` works the same as `--allow-read`.
-This is an example to restrict host.
+This example restricts network access by whitelisting the allowed hosts:
```ts
const result = await fetch("https://deno.land/");
