:~/ubuntu$ apt-get source nautilus
Reading package lists... Done
Building dependency tree
Reading state information... Done
NOTICE: 'nautilus' packaging is maintained in the 'Bzr' version control system at:
https://code.launchpad.net/~ubuntu-desktop/nautilus/ubuntu
Please use:
bzr branch https://code.launchpad.net/~ubuntu-desktop/nautilus/ubuntu
to retrieve the latest (possibly unreleased) updates to the package.
Need to get 4999 kB of source archives.
Get:1 http://archive.ubuntu.com/ubuntu/ quantal/main nautilus 1:3.5.4-0ubuntu2 (dsc) [2222 B]
Get:2 http://archive.ubuntu.com/ubuntu/ quantal/main nautilus 1:3.5.4-0ubuntu2 (tar) [4939 kB]
Get:3 http://archive.ubuntu.com/ubuntu/ quantal/main nautilus 1:3.5.4-0ubuntu2 (diff) [57.2 kB]
Fetched 4999 kB in 4s (1069 kB/s)
sh: 1: dpkg-source: not found
Unpack command 'dpkg-source -x nautilus_3.5.4-0ubuntu2.dsc' failed.
Check if the 'dpkg-dev' package is installed.
E: Child process failed