RUBYOPT
Additional command-line options to Ruby; examined after REAL command-line options are parsed ($SAFE must be 0).

RUBYLIB
Additional search path for Ruby PROGRAMS ($SAFE must be 0).

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

RUBYSHELL
Shell to use when spawning a process; if not SET, will also check SHELL or COMSPEC. DLN_LIBRARY_PATH Search path for dynamically loaded modules.

RUBYLIB_PREFIX
(Windows only) MANGLE the RUBYLIB search path by adding this prefix to each component.

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

RUBYLIB
Additional search path for Ruby programs ($SAFE must be 0).

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

RUBYSHELL
Shell to use when spawning a process; if not set, will also check SHELL or COMSPEC. DLN_LIBRARY_PATH Search path for dynamically loaded modules.

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