yonkeltron@Akiba:~$ jruby1.0 -h
Usage: jruby [switches] [--] [rubyfile.rb] [arguments]
-e 'command' one line of script. Several -e's allowed. Omit [programfile]
-b benchmark mode, times the script execution
-Jjava option pass an option on to the JVM (e.g. -J-Xmx512m)
-Idirectory specify $LOAD_PATH directory (may be used more than once)
-- optional -- before rubyfile.rb for compatibility with ruby
-d set debugging flags (set $DEBUG to true)
-v print version number, then turn on verbose mode
-O run with ObjectSpace disabled (improves performance)
-S cmd run the specified command in JRuby's bin dir
-C pre-compile scripts before running (EXPERIMENTAL)
-y read a YARV-compiled Ruby script and run that (EXPERIMENTAL)
-Y compile a Ruby script into YARV bytecodes and run this (EXPERIMENTAL)
--command word Execute ruby-related shell command (i.e., irb, gem)