Lost/Deleted dpkg (package manager for Debian). How do I get it back?

Question

OS: Ubuntu 12.04

Accidentally deleted dpkg. Now, packages can't be installed. So, needs an dpkg installer which installs packages.

Answer 1

Depending exactly what you removed, you may be able to rescue the situation by extracting the necessary parts from a manually downloaded .deb file. The trick, of course, is finding a way to unpack the .deb file without a working dpkg - fortunately there's a solution here

How to extract and install .deb without the command dpkg?

---

First go to packages.ubuntu.com and download the appropriate .deb file for your OS version and architecture e.g.

mkdir debroot && cd debroot
wget https://mirrors.edge.kernel.org/ubuntu/ubuntu/pool/main/d/dpkg/dpkg_1.22.6ubuntu6_amd64.deb

Now unpack the deb file using ar in place of the usual dpkg -x

ar -x dpkg_1.22.6ubuntu6_amd64.deb

(replace dpkg_1.22.6ubuntu6_amd64.deb with name of the actual deb that you downloaded). You should now have the following contents

control.tar.gz  data.tar.gz  debian-binary  dpkg_1.22.6ubuntu6_amd64.deb

The package's files should be located in the data.tar.gz so to extract the dpkg binary file locally

tar xf data.tar.gz ./usr/bin/dpkg

If that worked, you should have a file at ./usr/bin/dpkg which you can copy to your /usr/bin directory

sudo cp ./usr/bin/dpkg /usr/bin/

[Note that you could untar the file directly relative to / using sudo tar -C ... but doing it in two steps just feels a little safer.]

---

If that works, I'd recommend re-installing the whole thing from the repository for consistency i.e.

sudo apt-get update
sudo apt-get install --reinstall dpkg

(on newer systems, you can replace apt-get by apt).

Answer 2

Download the dpkg package for your release from https://launchpad.net/ubuntu/+source/dpkg/.

Extract the file.

cd to the root of the dpkg source directory.

./configure
make
sudo make install

You may need to download some packages if ./configure fails