NAME

     irb — Interactive Ruby Shell

SYNOPSIS

     irb [--version] [-dfUw] [-I directory] [-r library] [-E external[:internal]] [-W[level]]
         [--[no]inspect] [--[no]multiline] [--[no]singleline] [--[no]echo] [--[no]colorize]
         [--[no]autocomplete] [--[no]verbose] [--prompt mode] [--prompt-mode mode]
         [--inf-ruby-mode] [--simple-prompt] [--noprompt] [--tracer] [--back-trace-limit 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.

     -w             Same as `ruby -w' .

     -W             Same as `ruby -W' .

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

     -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

     --multiline    Uses multiline editor module.

     --nomultiline  Doesn't use multiline editor module.

     --singleline   Uses singleline editor module.

     --nosingleline
                    Doesn't use singleline editor module.

     --extra-doc-dir
                    Add an extra doc dir for the doc dialog.

     --echo         Show result (default).

     --noecho       Don't show result.

     --echo-on-assignment
                    Show result on assignment.

     --noecho-on-assignment
                    Don't show result on assignment.

     --truncate-echo-on-assignment
                    Show truncated result on assignment (default).

     --colorize     Use colorization.

     --nocolorize   Don't use colorization.

     --autocomplete
                    Use autocompletion.

     --noautocomplete
                    Don't use autocompletion.

     --verbose      Show details.

     --noverbose    Don't show details.

     --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 --multiline
                    and --singleline.

     --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.

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.