### Keys with dots
When specifying a key that has a dot use key lookup indicator.

```yaml
b:
  foo.bar: 7
```

```bash
yaml r sample.yaml 'b[foo.bar]'
```

```bash
yaml w sample.yaml 'b[foo.bar]' 9
```

Any valid yaml key can be specified as part of a key lookup.

Note that the path is in quotes to avoid the square brackets being interpreted by your shell.