Building Debian Packages from the Ground Up/

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Extracting the Control Tarball

Extracting the Control Tarball

Learn what's inside the control tarball and which functionality these files perform.

We'll cover the following...

Contents of the control.tar.gz file

Let’s look at the structure of control.tar.gz extracted from bash_4.4-5_amd64.deb.

  • ./conffiles
  • ./control
  • ./md5sums
  • ./postinst
  • ./postrm
  • ./preinst
  • ./prerm

Let’s explore these files one by one and see what functions these files perform.

The conffiles file

The conffiles file contains a list of file names that Debian considers configuration files. For the purpose of the package manager, a configuration file is one that we expect the user to change, so it can’t overwrite a configuration file that a user changed:

$ cat conffiles

Here are the contents of conffiles:

/etc/bash.bashrc
/etc/skel/.bash_logout
/etc/skel/.bashrc
/etc/skel/.profile
Content of conffiles

The md5sums file

The md5sums file contains MD5 checksums for each file in the package. This is useful for the packaging tools to be able to detect corrupt or incomplete files:

$ head -n3 md5sums

Below is the content ...