These jirb commands are entered in a terminal window or command window, depending on your operating system.

 $ jirb --help
 Usage:  irb.rb [options] [programfile] [arguments]
   -f                Suppress read of ~/.irbrc
   -m                Bc mode (load mathn, fraction or matrix are available)
   -d                Set $DEBUG to true (same as `ruby -d')
   -r load-module    Same as `ruby -r'
   -I path           Specify $LOAD_PATH directory
   --inspect         Use `inspect' for output (default except for bc mode)
   --noinspect       Don't use inspect for output
   --readline        Use Readline extension module
   --noreadline      Don't use Readline extension module
   --prompt prompt-mode
   --prompt-mode prompt-mode
                     Switch prompt mode. Pre-defined prompt modes are
                     `default', `simple', `xmp' and `inf-ruby'
   --inf-ruby-mode   Use prompt appropriate for inf-ruby-mode on emacs.
                     Suppresses --readline.
   --simple-prompt   Simple prompt mode
   --noprompt        No prompt mode
   --tracer          Display trace for each execution of commands.
   --back-trace-limit n
                     Display backtrace top n and tail n. The default
                     value is 16.
   --irb_debug n     Set internal debug level to n (not for popular use)
   -v, --version     Print the version of irb