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
           => 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
           %

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.

     And you can report other bugs and feature requests via the Ruby Issue Tracking System
     (http://bugs.ruby-lang.org).  Do not report security vulnerabilities via the system because
     it publishes the vulnerabilities immediately.

AUTHORS

     Written by Keiju ISHITSUKA.