Here is a table of the action arguments and options:
Visit file using find-file. Section 16.2.
Visit file using find-file, then go to line number linenum in it.
Load a Lisp library named file with the function load. Section 25.7. The library can be found either in the current directory, or in the Emacs library search path as specified with EMACSLOADPATH (Section B.5.1).
Call Lisp function function with no arguments.
Evaluate Lisp expression expression.
Insert the contents of file into the current buffer. This is like what M-x insert-file does. Section 16.10.
Exit from Emacs without asking for confirmation.
The init file can access the values of the action arguments as the elements of a list in the variable command-line-args. The init file can override the normal processing of the action arguments, or define new ones, by reading and setting this variable.