eemi

$i = (Get-NetAdapter | ? { $_.Status -eq 'Up' -and $_.MediaType -eq '802.3' } | select -First 1).ifIndex
"Cable ifIndex: $i"
ping -n 2 "ff02::1%$i" | Out-Null
Get-NetNeighbor -InterfaceIndex $i | ? { $_.State -notin 'Unreachable','Permanent' } | ft IPAddress, LinkLayerAddress, State

eemi

Based on https://docs.docker.com/compose/rails/

Dockerfile

FROM ruby:2.5.1
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
RUN mkdir /site

eemi

brew doctor
Your system is raring to brew.