IRB(1)

NAME
irb - Interactive Ruby Shell

SYNOPSIS
irb [--version] [-dfm] [-I directory] [-r library] [--[no]inspect] [--[no]readline] [--prompt mode] [--prompt-mode mode] [--inf-ruby-mode] [--simple-prompt] [--noprompt] [--tracer] [--back-trace-limit n] [--irb_debug n] [--] [program_file] [argument ...]

DESCRIPTION
irb is the REPL(read-eval-print loop) environment for Ruby programs.

OPTIONS

--version
    Prints the version of irb.

-E external[:internal]
--encoding external[:internal]
    Same as `ruby -E' . Specifies the default value(s) for external encodings and internal encoding. Values should be separated with colon (:).

    You can omit the one for internal encodings, then the value (Encoding.default_internal) will be nil.

-I path
    Same as `ruby -I' . Specifies $LOAD_PATH directory

-U  Same as `ruby -U' . Sets the default value for internal encodings (Encoding.default_internal) to UTF-8.

-d  Same as `ruby -d' . Sets $DEBUG to true.

-f  Suppresses read of ~/.irbrc.

-h
--help
    Prints a summary of the options.

-m  Bc mode (load mathn, fraction or matrix are available)

-r library
    Same as `ruby -r'. Causes irb to load the library using require.

--inspect
    Uses `inspect' for output (default except for bc mode)

--noinspect
    Doesn't use inspect for output

--readline
    Uses Readline extension module.

--noreadline
    Doesn't use Readline extension module.

--prompt mode
--prompt-mode mode
    Switch prompt mode. Pre-defined prompt modes are `default', `simple', `xmp' and `inf-ruby'.

--inf-ruby-mode
    Uses prompt appropriate for inf-ruby-mode on emacs. Suppresses --readline.

--simple-prompt
    Makes prompts simple.

--noprompt
    No prompt mode.

--tracer
    Displays trace for each execution of commands.

--back-trace-limit n
    Displays backtrace top n and tail n. The default value is 16.

--irb_debug n
    Sets internal debug level to n (not for popular use)

ENVIRONMENT
IRBRC

Also irb depends on same variables as ruby(1).

FILES
~/.irbrc
    Personal irb initialization.

EXAMPLES
    % irb
    irb(main):001:0> 1 + 1
    2
    irb(main):002:0> def t(x)
    irb(main):003:1> x+1
    irb(main):004:1> end
    => :t
    irb(main):005:0> t(3)
    => 4
    irb(main):006:0> if t(3) == 4
    irb(main):007:1> p :ok
    irb(main):008:1> end
    :ok
    => :ok
    irb(main):009:0> quit
    %

SEE ALSO
ruby(1).

REPORTING BUGS

•   Security vulnerabilities should be reported via an email to security@ruby-lang.org. Reported problems will be published after being fixed.

•   Other bugs and feature requests can be reported via the Ruby Issue Tracking System (https://bugs.ruby-lang.org/). Do not report security vulnerabilities via this system because it publishes the vulnerabilities immediately.

AUTHORS
Written by Keiju ISHITSUKA.