audacity software package provides fast, cross-platform audio editor, 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 audacity
audacity is installed in your system.
Make ensure the audacity package were installed using the commands given below,
$ sudo dpkg-query -l | grep audacity *
You will get with audacity package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Sound |
| Package | audacity |
| Version | 2.1.2-1+b1 |
| Description | fast, cross-platform audio editor |
| Sub Section | Sound |