Para desinstalar somente hardening-includes do Debian 9 (Stretch) execute no terminal:
sudo apt-get remove hardening-includes
Desinstalar hardening-includes e os pacotes dependentes
Para desinstalar o pacote hardening-includes e quaisquer outros pacotes dependentes que não sejam mais necessários do Debian Stretch.
sudo apt-get remove --auto-remove hardening-includes
Se você também deseja limpar as configurações e/ou dados de hardening-includes do Debian Stretch então use este comando:
sudo apt-get purge hardening-includes
Para limpar as configurações e/ou arquivos de dados do hardening-includes e de seus pacotes dependentes do Debian Stretch execute:
sudo apt-get purge --auto-remove hardening-includes
More information about apt-get remove
Advanced Package Tool, or APT, is a free software user interface that works with core libraries to handle the installation and removal of software on Debian, Ubuntu and other Linux distributions. APT simplifies the process of managing software on Unix-like computer systems by automating the retrieval, configuration and installation of software packages, either from precompiled files or by compiling source code.
apt-get is the command-line tool for handling packages, and may be considered the user's "back-end" to other tools using the APT library.
apt-get remove is identical to install except that packages are removed instead of installed. Note that removing a package leaves its configuration files on the system. If a plus sign is appended to the package name (with no intervening space), the identified package will be installed instead of removed.