Aditional command-line options to Ruby; examined after real command-line options are parsed ($SAFE must be 0)

Aditional search path for Ruby programs ($SAFE must be 0)

With -S option search path for Ruby programs (defaults to PATH)

Shell to use when spawning a process; if not set, will also check SHELL or COMSPEC

Search path for dynamically loaded modules.

(Windows only) Mangle the RUBILIB search path by adding this prefix to each component.