irb2.11

Usage

Overview

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

=> nil

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

%