Getting Source of an Installed Package on Ubuntu

This is a little tutorial that goes over how to find a system installed python application, find out what package it comes from, and get the source and package build information. This can be useful for a variety of reasons from looking at how to package specific types of application or just to see the source of the application you are running. This is done on Ubuntu, but would work on any Debian based distribution.

Lets hop on over to /usr/bin and see what runs python in a very simple way.

cd /usr/bin
grep /usr/bin/python *
2to3:#! /usr/bin/python2.7
2to3-2.7:#! /usr/bin/python2.7
2to3-3.5:#! /usr/bin/python3.5
add-apt-repository:#! /usr/bin/python3
alacarte:#! /usr/bin/python -OOt
apport-cli:#!/usr/bin/python3
apport-unpack:#!/usr/bin/python3
apt-add-repository:#! /usr/bin/python3
aptdcon:#! /usr/bin/python3
apturl-gtk:#!/usr/bin/python3
chardet3:#! /usr/bin/python3
chardetect3:#! /usr/bin/python3
check-language-support:#! /usr/bin/python3
createfontdatachunk:#! /usr/bin/python3
createfontdatachunk.py:#! /usr/bin/python
dcut:#!/usr/bin/python
debmake:#!/usr/bin/python3
...

The list goes on and on. We can see there's a mixture of python2 and python3 apps on my system. Now, lets pick out one of those /usr/bin files, particularly /usr/bin/alacarte and see what package it comes from.

dpkg -S /usr/bin/alacarte
alacarte: /usr/bin/alacarte

Before we can download the source, we need to make sure we have source repositories enabled in apt. These are usually not enabled by default, but your mileage may vary.

sudoedit /etc/apt/sources.list

Uncomment the source lines for the main release. For me, that's this line.

deb-src http://us.archive.ubuntu.com/ubuntu/ xenial main restricted

Save and exit. Now, update.

sudo apt-get update

Now, get the source.

cd ~
apt-get source alacarte

Notice no sudo on the apt-get source. This results in the following files and directory being download to the current working directory containing all of the application source and package source. From here you can inspect their contents.

alacarte-3.11.91
alacarte_3.11.91-2.debian.tar.xz
alacarte_3.11.91-2.dsc
alacarte_3.11.91.orig.tar.xz