ioreg

On macOS, ioreg returns the structured output of the ioreg -a -l command, which includes detailed information about the I/O Kit registry.

On non-macOS operating systems, ioreg returns nil.

The output from ioreg is cached so multiple calls to the ioreg function will only execute the ioreg -a -l command once.

!!! example

```
{{ if eq .chezmoi.os "darwin" }}
{{   $serialNumber := index ioreg "IORegistryEntryChildren" 0 "IOPlatformSerialNumber" }}
{{ end }}
```

!!! warning

The `ioreg` function can be very slow and should not be used. It will be
removed in a later version of chezmoi.