Problem Statement

Show how to specify and execute a short program in the language from a command shell, where the input to the command shell is only one line in length. Avoid depending on the particular shell or operating system used as much as is reasonable; if the language has notable implementations which have different command argument syntax, or the systems those implementations run on have different styles of shells, it would be good to show multiple examples.

Let's start with the solution:

rdmd --eval="writeln(q{Hello World!})"