dpkg -s <package> - allows you to
find the version of that
you have installed. (source)
apt-cache showpkg <package> - will
show a list of Versions of the
package available. For each version,
the source of the package, in the
form of an index file name, will be
If you want to find the source of the package that's currently installed, you'll need the output of
dpkg -s <package>. Otherwise, you can simply look at the newest version output by
apt-cache showpkg <package>.
mac9416@lizzy:~$ dpkg -s liferea
Status: install ok installed
Maintainer: Ubuntu Developers <firstname.lastname@example.org>
mac9416@lizzy:~$ apt-cache showpkg liferea
1.6.2-1ubuntu6 (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid_main_binary-i386_Packages) (/var/lib/dpkg/status)
From the first command, I can see that Liferea version 1.6.2-1ubuntu6 is installed. From the second command, I can see that that version is listed in
Without too much effort, I can deduce that the source line contains "archive.ubuntu.com", "ubuntu", "lucid", and "main".
And, sure enough, my
/etc/apt/sources.list contains the following line.
deb http://archive.ubuntu.com/ubuntu lucid main universe restricted multiverse