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APT Files
Chapter 1 Introduction

1.1 General

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/
     		  xstatus
     		  userstatus
     		  cdroms.list
       /var/cache/apt/
                       pkgcache.bin
     		  srcpkgcache.bin
     		  archives/
     		          partial/
       /etc/apt/
                sources.list
     	   apt.conf
       /usr/lib/apt/
                     methods/
     		       cdrom
     		       ftp
     		       http
     		       file
     		       gzip
     		       copy

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.