Cannot download build-dep for indicator-sound [duplicate]

Question

I'm trying to do this, but when I execute sudo apt-get build-dep indicator-sound, i get E: You must put some 'source' URIs in your sources.list. I did not get this error in pervious ubuntu versions, only in 16.04. What sources do I need to add in order to download indicator-sound sources? Thanks!

Edit1:

I can now execute sudo apt-get build-dep indicator-sound, but all I get is :

Reading package lists... Done
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 16 not upgraded.

It appeares that I haven't downloaded anything. :(

Edit2: This question is not a duplicate of this one. As you can read in edit1, I cannot download the actual folder with source files.

Edit3: I just realized, I also get these errors when I run sudo apt-get update:

W: Target Sources (restricted/source/Sources) is configured multiple times in /etc/apt/sources.list:2 and /etc/apt/sources.list:7
W: Target Sources (restricted/source/Sources) is configured multiple times in /etc/apt/sources.list:2 and /etc/apt/sources.list:7

Edit4: I followed this, and it worked. Thanks!

Answer 1

To edit your sources.list first you might want to make a backup copy

sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup

then:

sudo nano /etc/apt/sources.list

all the deb-src... lines are commented out by default. You actually only need to uncomment the first one. Change this:

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

to this:

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

save and exit and you will be able to run

sudo apt update && sudo apt build-dep indicator-sound

and in your home (it's a good idea to make a directory to unpack sources because they unpack to multiple files so this keeps them together)

mkdir indicator-sound; cd indicator-sound
apt source indicator-sound

Answer 2

You need to be able to download source code from the Ubuntu repositories. The GUI way of doing this is:

1. Press Super to start the Dash and search for "Software & Updates".

2. Check the "Source code" box as shown below:

   

3. Press "Close" and agree to reload sources.list.