attic software package provides deduplicating backup program, 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 attic
attic is installed in your system.
Make ensure the attic package were installed using the commands given below,
$ sudo dpkg-query -l | grep attic *
You will get with attic package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Administration Utilities |
| Package | attic |
| Version | 0.13-1+b1 [s390x], 0.13-1 [amd |
| Description | deduplicating backup program |
| Sub Section | admin |