Usage: irb.rb [options] [programfile] [arguments]

-f                Don't initialize from configuration file.
-d                Set $DEBUG and $VERBOSE to true (same as 'ruby -d').
-r load-module    Require load-module (same as 'ruby -r').
-I path           Specify $LOAD_PATH directory (same as 'ruby -I').
-U                Set external and internal encodings to UTF-8.
-E ex[:in]        Set default external (ex) and internal (in) encodings
                  (same as 'ruby -E').
-w                Suppress warnings (same as 'ruby -w').
-W[level=2]       Set warning level: 0=silence, 1=medium, 2=verbose
                  (same as 'ruby -W').
--context-mode n  Set n[0-4] to method to create Binding Object,
                  when new workspace was created.
--extra-doc-dir   Add an extra doc dir for the doc dialog.
--echo            Show result (default).
--noecho          Don't show result.
--echo-on-assignment
                  Show result on assignment.
--noecho-on-assignment
                  Don't show result on assignment.
--truncate-echo-on-assignment
                  Show truncated result on assignment (default).
--inspect         Use 'inspect' for output.
--noinspect       Don't use 'inspect' for output.
--no-pager        Don't use pager.
--multiline       Use multiline editor module (default).
--nomultiline     Don't use multiline editor module.
--singleline      Use single line editor module.
--nosingleline    Don't use single line editor module (default).
--colorize        Use color-highlighting (default).
--nocolorize      Don't use color-highlighting.
--autocomplete    Use auto-completion (default).
--noautocomplete  Don't use auto-completion.
--regexp-completor
                  Use regexp based completion (default).
--type-completor  Use type based completion.
--prompt prompt-mode, --prompt-mode prompt-mode
                  Set prompt mode. Pre-defined prompt modes are:
                  'default', 'classic', 'simple', 'inf-ruby', 'xmp', 'null'.
--inf-ruby-mode   Use prompt appropriate for inf-ruby-mode on emacs.
                  Suppresses --multiline and --singleline.
--sample-book-mode, --simple-prompt
                  Set prompt mode to 'simple'.
--noprompt        Don't output prompt.
--script          Script mode (default, treat first argument as script)
--noscript        No script mode (leave arguments in argv)
--single-irb      Share self with sub-irb.
--tracer          Show stack trace for each command.
--back-trace-limit n[=16]
                  Display backtrace top n and bottom n.
--verbose         Show details.
--noverbose       Don't show details.
-v, --version     Print the version of irb.
-h, --help        Print help.
--                Separate options of irb from the list of command-line args.