Not sure if it still works. If it does work it requires that your user is subscribed to Spotify Premium I believe.
https://github.com/ArtemGordinsky/SpotiFree
http://spotifree.gordinskiy.com/
DISCLAIMER: This has nothing to do with command-line anything, it's just a useful project I discovered and wanted to share.
Mopidy supports local files, Spotify, Soundcloud and Google Play Music, all mixed in the same playlists.
http://docs.mopidy.com/en/latest/ext/external/#mopidy-soundc...
So, it doesn't have a command line client, it's a website that offers a text based interface to SoundCloud.
I don't think this is what most people would associate with 'command line client' though, while the linked GH project actually allows access to SoundCloud data from the command line/shell.
$ sudo apt-get install portaudio19-dev libmpg123-dev libncurses-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'libncurses5-dev' instead of 'libncurses-dev'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
portaudio19-dev : Depends: libjack-dev
E: Unable to correct problems, you have held broken packages. pip install soundscrape
soundscrape black-moth-super-rainbow
https://github.com/Miserlou/SoundScrape