From the Terminal
When launching Spotify in Linux by default the deb package comes with a desktop file that contains an exec that essentially just runs the "spotify" binary. Spotify does have a dbus interface for certain things. We can look for an existing process and if one is found we throw the Spotify link into dbus instead of opening another Spotify instance.
I wrote a simple launcher replacement. Just set your desktop file to use this instead of the default.
What's going on?
kde-open5 is breaking the links by making all characters lowercase.
Get the link by running:
while sleep .1; do ps aux | grep slack | grep -v grep | grep magic; done
Then just run `
xdg-open [the link]`
The link should look like this: