acpi software package provides displays information on ACPI devices, 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 acpi
acpi is installed in your system.
Make ensure the acpi package were installed using the commands given below,
$ sudo dpkg-query -l | grep acpi *
You will get with acpi package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Utilities |
| Package | acpi |
| Version | 1.7-1 |
| Description | displays information on ACPI devices |
| Sub Section | Utils |