aseqdump

aseqdump [options] [port ...]

-h, --help
    Show help message and exit.

-V, --version
    Show version number and exit.

-l, --list
    List all available ports.

-p port, --port port
    Select a specific port to monitor (e.g., 14:0).

-s, --system
    Dump system client events only.

-d, --destination
    Dump destination client events only.

-S, --source
    Dump source client events only.

-x, --hex
    Show raw hex data.

-a, --ascii
    Show ascii data (useful to check received SysEx).

-q, --queue
    Show queue number.

-r, --rawport
    Use raw port (no timestamp).

port ...
    One or more ALSA sequencer port numbers to monitor.

The aseqdump command is a utility for monitoring and capturing ALSA sequencer events.
It provides a human-readable representation of the MIDI and system events that are being transmitted through the ALSA sequencer subsystem.
This command allows you to see exactly what MIDI data is being sent and received by your MIDI devices, making it useful for debugging MIDI applications, understanding MIDI protocols, and analyzing MIDI streams.
It's invaluable for developers working with MIDI, musicians troubleshooting MIDI setups, and anyone who needs to understand the flow of MIDI data on a Linux system.
Aseqdump captures ALSA sequencer events and presents them on the standard output. It's a diagnostic tool, not intended for real-time processing.
Filters can be applied to display specific types of data to make the process easier to analyze.

• To monitor all sequencer events: aseqdump
• To monitor a specific port (e.g., port 14:0): aseqdump -p 14:0
• To display raw hex data: aseqdump -x

aseqdump is part of the ALSA (Advanced Linux Sound Architecture) project.
It was developed to provide a way to inspect and debug MIDI communication within the ALSA framework.
Its development is closely tied to the overall evolution of ALSA, and it has been a standard tool for MIDI developers and users on Linux for many years.

amidi(1), aconnect(1)