deb-preinst - package pre-installation maintainer script

Description

A package can perform several pre-installation actions via maintainer scripts, by including an executable preinst file in its control archive (i.e. DEBIAN/preinst during package creation). The script can be called in the following ways: new-preinstinstall Before the package is installed. new-preinstinstallold-versionnew-version Before a removed package is upgraded. The new-version is passed only since dpkg 1.18.5. new-preinstupgradeold-versionnew-version Before the package is upgraded. The new-version is passed only since dpkg 1.18.5. old-preinstabort-upgradenew-version If postrm fails during upgrade or fails on failed upgrade.