Install gmidimonitor by entering the following commands in the terminal:
sudo apt update sudo apt install gmidimonitor
Description:
GTK+ application that shows MIDI events
GMIDImonitor is GTK+ application that shows MIDI events. . You need to connect desired source of MIDI events to gmidimonitor input using some kind of patchbay like qjackctl, patchage. For restoring connections (not connecting every time) you can use LASH.
Homepage: http://home.gna.org/gmidimonitor/
Version: 3.6+dfsg0-3
Section: universe/sound