The following command worked fine on Ubuntu 15.10:

sudo apt-get build-dep emacs24

However, on Ubuntu 16.04 I get the following error when running it:

Reading package lists... Done
E: You must put some 'source' URIs in your sources.list

In 15.10 all lines (around 10 in number) with deb-src in /etc/apt/sources.list where uncommented, whereas in 16.04 the corresponding lines where commented out. For example, here are 4 lines from my current sources.list:

## Major bug fix updates produced after the final release of the
## distribution.
deb http://no.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
# deb-src http://no.archive.ubuntu.com/ubuntu/ xenial-updates main restricted

What is the reason for this change?

Next, I would like to avoid manually edit /etc/apt/sources.list each time I do a reinstallation of Ubuntu. How can this (uncommenting the deb-src lines) be done automatically?

  • The reason is probably that for most users it's useless time/bandwidth wasting to update the database of available source packages every time. From the GUI where you configure the used repositories, you can easily disable/enable (comment/uncomment) those lines. There are also some sed scripts around.
    – JanC
    Apr 23, 2016 at 17:30
  • The python3-software-properties package might be useful to write a Python script too.
    – JanC
    Apr 23, 2016 at 17:43
  • @JanC Thanks, I wrote my own script. See answer below. Apr 23, 2016 at 17:55
  • 1
    CLI only version: askubuntu.com/questions/496549/… Dec 5, 2016 at 21:17

5 Answers 5


I had this same issue on a server install of Ubuntu 16.04, so no GUI. All that I needed was a couple of sed commands.

sudo sed -i -- 's/#deb-src/deb-src/g' /etc/apt/sources.list && sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list

Then sudo apt-get update and continue on.

  • This worked on 18.04
    – Matthew
    Aug 24, 2021 at 16:11

Open Software & Updates and enable "Source code".

  • 16
    Useless if your ubuntu is a server with just shell Sep 1, 2016 at 9:26

Here is a (currently untested) Bash script that could be used to uncomment deb-src lines in sources.list :

tempdir=$(mktemp -d)
cd "$tempdir"
perl -pE 's/^#\s+(deb-src)/$1/' "$source_file" > "$new_file"
sudo cp "$new_file" "$source_file"
sudo apt-get update
  • No need for a script. Please see my answer. Apr 23, 2016 at 19:28

simpler solution that does what the others have posted more succinctly:

sudo perl -p -i -n -e "s/# *deb-src/deb-src/"  /etc/apt/sources.list

Key distinctions: Perl has the -i inplace option which modifies files in place; I did not add a suffix for backup files because I didn't want the backup files to accidentally be treated as data files. And " *" deals with optional whitespace. "perl -p -n -e" is mostly the same as "sed -e", though watch out for greedy regex matching.

It has the same limitations the others do: it enables sources even if the original wasn't enabled (i.e. partners), and it doesn't work on /etc/apt/sources.list.d. The following will also process /etc/apt/sources.list.d* but makes a backup first.

(cd /etc/apt/; sudo tar cvf sources.list.tar sources.list sources.list.d);  for i in /etc/apt/sources.list /etc/apt/sources.list.d/*; do sudo perl -p -i -n -e "s/# *deb-src/deb-src/" $i; done

Here is a simplification of @Tobi's result that does it on a single call to sed:

sed -i -- 's/#\s\?deb-src/deb-src/g' /etc/apt/sources.list

This adds \s\? which is an optional white space (note the ? needs to be escaped).

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