jack-stdio software package provides program to pipe audio-data from and to JACK, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install jack-stdio
jack-stdio is installed in your system.
Make ensure the jack-stdio package were installed using the commands given below,
$ sudo dpkg-query -l | grep jack-stdio *
You will get with jack-stdio package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Sound |
| Package | jack-stdio |
| Version | 1.4-1+b1 [armhf], 1.4-1 [amd64 |
| Description | program to pipe audio-data from and to JACK |
| Sub Section | Sound |