1IRB(1)                 Ruby Programmer's Reference Guide                IRB(1)
2

NAME

4     irb — Interactive Ruby Shell
5

SYNOPSIS

7     irb [--version] [-dfm] [-I directory] [-r library] [--[no]inspect]
8         [--[no]readline] [--prompt mode] [--prompt-mode mode]
9         [--inf-ruby-mode] [--simple-prompt] [--noprompt] [--tracer]
10         [--back-trace-limit n] [--irb_debug n] [--] [program_file]
11         [argument ...]
12

DESCRIPTION

14     irb is the REPL(read-eval-print loop) environment for Ruby programs.
15

OPTIONS

17     --version      Prints the version of irb.
18
19     -E external[:internal]
20     --encoding external[:internal]
21                    Same as `ruby -E' .  Specifies the default value(s) for
22                    external encodings and internal encoding. Values should be
23                    separated with colon (:).
24
25                    You can omit the one for internal encodings, then the
26                    value (Encoding.default_internal) will be nil.
27
28     -I path        Same as `ruby -I' .  Specifies $LOAD_PATH directory
29
30     -U             Same as `ruby -U' .  Sets the default value for internal
31                    encodings (Encoding.default_internal) to UTF-8.
32
33     -d             Same as `ruby -d' .  Sets $DEBUG to true.
34
35     -f             Suppresses read of ~/.irbrc.
36
37     -h
38     --help         Prints a summary of the options.
39
40     -r library     Same as `ruby -r'.  Causes irb to load the library using
41                    require.
42
43     --inspect      Uses `inspect' for output (default except for bc mode)
44
45     --noinspect    Doesn't use inspect for output
46
47     --readline     Uses Readline extension module.
48
49     --noreadline   Doesn't use Readline extension module.
50
51     --prompt mode
52     --prompt-mode mode
53                    Switch prompt mode. Pre-defined prompt modes are
54                    `default', `simple', `xmp' and `inf-ruby'.
55
56     --inf-ruby-mode
57                    Uses prompt appropriate for inf-ruby-mode on emacs.  Sup‐
58                    presses --readline.
59
60     --simple-prompt
61                    Makes prompts simple.
62
63     --noprompt     No prompt mode.
64
65     --tracer       Displays trace for each execution of commands.
66
67     --back-trace-limit n
68                    Displays backtrace top n and tail n.  The default value is
69                    16.
70
71     --irb_debug n  Sets internal debug level to n (not for popular use)
72

ENVIRONMENT

74     IRBRC
75
76     Also irb depends on same variables as ruby(1).
77

FILES

79     ~/.irbrc                          Personal irb initialization.
80

EXAMPLES

82           % irb
83           irb(main):001:0> 1 + 1
84           2
85           irb(main):002:0> def t(x)
86           irb(main):003:1> x+1
87           irb(main):004:1> end
88           => :t
89           irb(main):005:0> t(3)
90           => 4
91           irb(main):006:0> if t(3) == 4
92           irb(main):007:1> p :ok
93           irb(main):008:1> end
94           :ok
95           => :ok
96           irb(main):009:0> quit
97           %
98

SEE ALSO

100     ruby(1).
101

REPORTING BUGS

103     ·   Security vulnerabilities should be reported via an email to
104         security@ruby-lang.org.  Reported problems will be published after
105         being fixed.
106
107     ·   Other bugs and feature requests can be reported via the Ruby Issue
108         Tracking System (https://bugs.ruby-lang.org/).  Do not report secu‐
109         rity vulnerabilities via this system because it publishes the vulner‐
110         abilities immediately.
111

AUTHORS

113     Written by Keiju ISHITSUKA.
114
115UNIX                            April 20, 2017                            UNIX