awk is a virtual package provided by
Trying to install it directly yields:
Reading package lists... Done Building dependency tree Reading state information... Done Package awk is a virtual package provided by: original-awk:i386 2012-12-20-4 mawk:i386 1.3.3-17ubuntu2 gawk:i386 1:4.1.1+dfsg-1 original-awk 2012-12-20-4 mawk 1.3.3-17ubuntu2 gawk 1:4.1.1+dfsg-1 You should explicitly select one to install. E: Package 'awk' has no installation candidate
However many virtual packages are needed as dependencies by the packages installed by default, for example
awk itself is needed by
base-files, which checking the APT logs is installed along with a bunch of other packages through
apt-get --yes; somehow APT ends up picking one of the three automatically (I'm pretty sure that's
mawk, but that's not the point of the question).
How does APT choose the specific package to install in this case?