aseqdump

aseqdump [-p client:port,...] [-l] [-u version] [-r] [-R|-N|-P]

aseqdump is a command-line utility that prints the ALSA sequencer events it receives as human-readable text. It is useful for debugging MIDI connections, testing keyboards, and monitoring MIDI data streams.The output shows event type, channel, note numbers, velocity, control changes, and other MIDI message details.

-h, --help

Print a list of options

Print the current version

Print a list of possible input ports

Set the sequencer port(s) from which events are received. A client can be specified by its number, its name, or a prefix of its name. A port is specified by its number; for port 0, the ":0" part can be omitted

Set the client MIDI version. 0 is for legacy mode, 1 is UMP MIDI 1.0 mode, and 2 is UMP MIDI 2.0 mode

Suppress the automatic conversion of events among UMP and legacy clients

Show the raw values as is. Channel numbers and UMP group numbers are 0-based. This is the default

Show normalized values aligned with MIDI 1.0. Channel and group numbers are 1-based, velocity and data values are normalized between 0 and 127

Show values as percentages. Channel and group numbers are 1-based

Only displays ALSA sequencer events, not raw MIDI. Subscribe to specific ports to filter output. Events are displayed but not recorded.

aseqdump is part of the alsa-utils package, providing MIDI debugging capabilities since ALSA's introduction.

aconnect(1), amidi(1), arecordmidi(1), aseqnet(1), aplaymidi(1)