irb — Interactive
    Ruby Shell
  
    | irb | [ --version] [-dfUw]
      [-Idirectory]
      [-rlibrary]
      [-Eexternal[:internal]]
      [-W[level]]
      [--[no]inspect]
      [--[no]multiline]
      [--[no]singleline]
      [--[no]echo]
      [--[no]colorize]
      [--[no]autocomplete]
      [--[no]verbose] [--promptmode] [--prompt-modemode] [--inf-ruby-mode]
      [--simple-prompt]
      [--noprompt] [--tracer]
      [--back-trace-limitn]
      [--] [program_file] [argument ...] | 
irb is the REPL(read-eval-print loop)
    environment for Ruby programs.
  - --version
- Prints the version of irb.
- -Eexternal[:internal]
-  
- --encodingexternal[: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.
 
- -Ipath
- Same as `ruby -I' . Specifies $LOAD_PATHdirectory
- -U
- Same as `ruby -U' . Sets the default value for internal encodings
      (Encoding.default_internal)to
      UTF-8.
- -d
- Same as `ruby -d' . Sets $DEBUGto true.
- -f
- Suppresses read of ~/.irbrc.
    
  
- -w
- Same as `ruby -w' .
    
  
- -W
- Same as `ruby -W' .
    
  
- -h
-  
- --help
- Prints a summary of the options.
    
  
- -rlibrary
- 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.
    
  
- 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.
    
  
- --regexp-completor
- Use regexp based completion.
    
  
- --type-completor
- Use type based completion.
    
  
- --verbose
- Show details.
    
  
- --noverbose
- Don't show details.
    
  
- --promptmode
-  
- --prompt-modemode
- 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-limitn
- Displays backtrace top n and tail
      n. The default value is 16.
  - IRB_LANG
- The locale used for irb.
- IRBRC
- The path to the personal initialization file.
    
  
- XDG_CONFIG_HOME
- irbrespects XDG_CONFIG_HOME. If it is set and- IRBRCis unset, load
      $XDG_CONFIG_HOME/irb/irbrc as a personal
      initialization file.
- The command specified would be used as a pager.
    
  
- The command specified would be used as a pager if
      RI_PAGERis unset.
- VISUAL
- Its value would be used to open files by the edit command.
    
  
- EDITOR
- Its value would be used to open files by the edit command if
      VISUALis unset.
- NO_COLOR
- Assigning a value to it disables colorization.
    
  
- IRB_USE_AUTOCOMPLETE
- Assigning
      false
      to it disables autocompletion.
    
  
- IRB_COMPLETOR
- Autocompletion behavior. Allowed values are
      regexp
      or type
    
  
- IRB_COPY_COMMAND
- Overrides the default program used to interface with the system
    clipboard.
Also irb depends on same variables as
    ruby(1).
  - ~/.irbrc
- Personal irb initialization. If IRBRCis set, read
      $IRBRC instead. IfIRBRCis not set andXDG_CONFIG_HOMEis set,
      $XDG_CONFIG_HOME/irb/irbrc is loaded.
% 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
%
  - 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.
Written by Keiju ISHITSUKA.