irb2.5 --version (return code: 0)
irb 0.9.6(09/06/30)
irb2.5 --help (return code: 0)
Usage: irb.rb [options] [programfile] [arguments]
-f Suppress read of ~/.irbrc
-d Set $DEBUG to true (same as `ruby -d')
-r load-module Same as `ruby -r'
-I path Specify $LOAD_PATH directory
-U Same as `ruby -U`
-E enc Same as `ruby -E`
-w Same as `ruby -w`
-W[level=2] Same as `ruby -W`
--context-mode n Set n[0-3] to method to create Binding Object,
when new workspace was created
--echo Show result(default)
--noecho Don't show result
--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.
--sample-book-mode/--simple-prompt
Simple prompt mode
--noprompt No prompt mode
--single-irb Share self with sub-irb.
--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)
--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