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CentOS 7.0 - man page for irb (centos section 1)

IRB(1)							 Ruby Programmers Reference Guide						    IRB(1)

irb -- Interactive Ruby Shell
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 ...]
irb is the REPL(read-eval-print loop) environment for Ruby programs.
--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)
IRBRC Also irb depends on same variables as ruby(1).
~/.irbrc Personal irb initialization.
% 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 %
Security vulnerabilities should be reported via an email to <>. Reported problems will be published after being fixed. And you can report other bugs and feature requests via the Ruby Issue Tracking System ( Do not report security vulnerabilities via the system because it publishes the vulnerabilities immediately.
Written by Keiju ISHITSUKA.
November 7, 2012 UNIX