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TLDR: irb (tldr-pages)

Interactive Ruby shell.

  • Start the interactive shell
    irb
IRB(1)                 Ruby Programmer's Reference Guide                IRB(1)

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]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.

     --echo         Show result(default).

     --noecho       Don't show result.

     --colorize     Use colorization.

     --nocolorize   Don't use colorization.

     --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 AT ruby-lang.org.  Re‐
         ported 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 be‐
         cause it publishes the vulnerabilities immediately.

AUTHORS
     Written by Keiju ISHITSUKA.

UNIX                            August 11, 2019                           UNIX
irb(1)
NAME SYNOPSIS DESCRIPTION OPTIONS
-E external[:internal] -I path Same as `ruby -I' . Specifies $LOAD_PATH directory -U Same as `ruby -U' . Sets the default value for internal encodings -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 -r library Same as `ruby -r'. Causes irb to load the library using require. --nosingleline --inf-ruby-mode --simple-prompt
ENVIRONMENT FILES EXAMPLES SEE ALSO REPORTING BUGS AUTHORS

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