Install all the dependencies without installing a package?

Question

How do I install all the dependencies needed for the PHP package without installing the actual package for APT?

Answer 1

Install the PHP package with all the dependencies, then uninstall the PHP package.

Answer 2

Using apt-get: apt-get -s install name_of_PHP_package shows what extra packages will be installed. To automate:

LC_ALL=C apt-get -s install |
awk '/^[^ ]/ {p=0}
     p {print}
     /^The following extra packages will be installed:/ {p=1}'

Using aptitude interactively: mark the PHP package for installation, press g, mark the automatically selected packages as manually requested with m, remove the initial package from the to-install list with -, and finally confirm the installation request with g again.