Table of Contents
This document serves two purposes. The first is to document the installed directory structure and the format and purpose of each file. The second purpose is to document how APT views the Debian archive and deals with multiple package files.
The var directory structure is as follows:
/var/lib/apt/ lists/ partial/ periodic/ extended_states cdroms.list /var/cache/apt/ archives/ partial/ pkgcache.bin srcpkgcache.bin /etc/apt/ sources.list.d/ apt.conf.d/ preferences.d/ trusted.gpg.d/ sources.list apt.conf apt_preferences trusted.gpg /usr/lib/apt/ methods/ bzip2 cdrom copy file ftp gpgv gzip http https lzma rred rsh ssh
As is specified in the FHS 2.1 /var/lib/apt is used for application data that is not expected to be user modified. /var/cache/apt is used for regeneratable data and is where the package cache and downloaded .debs go. /etc/apt is the place where configuration should happen and /usr/lib/apt is the place where the apt and other packages can place binaries which can be used by the acquire system of APT.