Using this mod you can install any package during starup by providing it through the environment variable INSTALL_PACKAGES. This is then passed into the installation command as such: apt install -y --no-install-recommends ... or apk add --no-cache ... for Alpine based images.

In any docker container arguments, set an environment variable DOCKER_MODS=linuxserver/mods:universal-package-install

If adding multiple mods, enter them in an array separated by |, such as DOCKER_MODS=linuxserver/mods:universal-package-install|linuxserver/mods:universal-stdout-logs. Similarly, for installing multiple packages separate them by |. E.g., to install rsync, git and nginx add the following lines to your docker compose service:

- DOCKER_MODS=linuxserver/mods:universal-package-install
- INSTALL_PACKAGES=rsync|git|nginx