.DEB

Introduction

A .deb file is a software package for Debian, Ubuntu, Linux Mint and the other Linux distributions built on Debian. It holds the files to install, a description of the package with the other packages it depends on, and scripts to run before and after installing or removing it. The dpkg tool installs it, and APT fetches packages and their dependencies from repositories.

Software

• dpkg (Debian and its derivatives)
• APT (Debian and its derivatives)
• GNU Binutils, whose ar unpacks the outer archive (Linux, macOS, Windows)
• 7-Zip (Windows)

Structure

A .deb file is an ar archive, the same simple format Unix uses for static libraries. It starts with the 8 bytes !<arch>\n, and each member after that has a 60-byte text header giving its name, date, owner, mode and size. A package has three members, always in this order:

• debian-binary, a text file holding the format version, 2.0.
• control.tar, compressed (as control.tar.gz, .xz or .zst), holding the control file that names the package and its version and dependencies, plus the install scripts.
• data.tar, compressed the same ways, holding the files to install, laid out as they will be on disk.