# install apt-src
sudo apt install apt-src

# make sure source repositories are enabled
grep "deb-src" /etc/apt/sources.list
# or
grep "deb-src" /etc/apt/sources.list.d/*


#building DOOM
#if you just want the source and you are going to manually build it you can:
apt-get source prboom-plus

#other wise use apt-src for auto compile/dependence/packaging
sudo apt install apt-src

mkdir src
cd src

apt-src install prboom-plus
apt-src build prboom-plus

# If you need a wad file
sudo apt install freedoom doom-wad-shareware

#run the binary (depending on your distro it might be prboom or a port of it)
./dsda-doom-*/debian/dsda-doom/usr/games/dsda-doom
./prboom-plus-*/debian/prboom-plus/usr/games/prboom-plus

#building nmap
apt-src install nmap
apt-src build nmap
./nmap-*/debian/nmap/usr/bin/nmap