Creating a dynamic library

[Tony]

I would like to know that command line (I am on Linux) I would 
use to compile a D file and create an object file that is 
suitable for a Linux dynamic library (.so).

I believe it is probably

dmd -c -fPIC my_file.d

Also, what is the command line to create a dynamic library from 
one or more object files that have been compiled for dynamic 
invocation?

dmd ??? -shared ???