Repackage (backup) installed debian packages

These commands let you backup one or all of your installed packages.

To backup one installed package

dpkg-repack xbmc

or all of them at once

dpkg-repack `dpkg --get-selections | grep install | cut -f1`

Both these commands will create .deb-packages in the directory you're currently in.

If you want to install one of the packages

dpkg -i package_name.deb

or all of them at once

dpkg -i *.deb

Very handy.