I am trying to be able to play, pause, chose next track or previous track from command line, but unfortunately no one seems to know how to do this (I have goggled repeatedly). I need it to be a command so that I can use it with blue proximity, so pause when I walk away. Are there any commands for this?
The Spotify client has supported the MPRIS2 DBUS specification for ~4 years. Simply put this means most media remote controls should be able to control it.
If you need command-line access, you can talk to it directly over DBUS. Here's an example I stole from Fran Diéguez:
For more commands, see the MPRIS2 Player specifications.