Ubuntu – What classifies an application as ‘installed’ in Ubuntu


I would like to know what causes Ubuntu and/or Synaptic to recognize a program as being installed.

  • Is there an equivalent of the Windows registry that an application has to have a entry in?
  • Does a program have to be installed from a .*deb package to be classified as installed and show up in Synaptic?
  • And where are files for an installed program usually kept? I know that configuration files are kept in /home/x/ but not much else.

Best Answer

dpkg, through apt or aptitude keeps a database of the installed software in /var/lib/dpkg/status.

You can learn more about this here.

My response is based on a response given in this forum discussion.

As @psusi pointed out, because apt and aptitude are merely front-ends to dpkg, it is actually dpkg that keeps track of packaging.