Ruby Associated Tools

Standard Ruby Tools:

The standard Ruby distribution contains useful tools along with the interpreter and standard libraries:

These tools help you debug and improve your Ruby programs without spending much effort. This tutorial will give you a very good start with these tools.

• RubyGems :
  RubyGems is a package utility for Ruby which installs Ruby software packages, and keeps them up to date.
• Ruby Debugger :
  To help deal with bugs, the standard distribution of Ruby includes a debugger. This is very similar to gdb utility which can be used to debug complex programs.
• Interactive Ruby (irb) :
  irb (Interactive Ruby) was developed by Keiju Ishitsuka. It allows you to enter commands at the prompt and have the interpreter respond as if you were executing a program. irb is useful to experiment with or to explore Ruby.
• Ruby Profiler :
  Ruby profiler helps you to improve the performance of a slow program by finding the bottleneck.

Additional Ruby Tools:

There are other useful tools that don't come bundled with the Ruby standard distribution. However, you do need to install them yourself.

• eRuby: Embeded Ruby :
  eRuby stands for embedded Ruby. It's a tool that embeds fragments of Ruby code in other files such as HTML files similar to ASP, JSP and PHP.
• ri: Ruby Interactive Reference :
  When you have a question about the behavior of a certain method, you can invoke ri to read the brief explanation of the method.

Ruby Predefined Constants

The following table lists all the Ruby's Predefined Constants.

NOTE: TRUE, FALSE, and NIL are backward-compatible. It's preferable to use true, false, and nil.

Constant Name	Description
TRUE	Synonym for true.
FALSE	Synonym for false.
NIL	Synonym for nil.
ARGF	An object providing access to virtual concatenation of files passed as command-line arguments or standard input if there are no command-line arguments. A synonym for $<.
ARGV	An array containing the command-line arguments passed to the program. A synonym for $*.
DATA	An input stream for reading the lines of code following the __END__ directive. Not defined if __END__ isn't present in code.
ENV	A hash-like object containing the program's environment variables. ENV can be handled as a hash.
RUBY_PLATFORM	A string indicating the platform of the Ruby interpreter.
RUBY_RELEASE_DATE	A string indicating the release date of the Ruby interpreter
RUBY_VERSION	A string indicating the version of the Ruby interpreter.
STDERR	Standard error output stream. Default value of $stderr.
STDIN	Standard input stream. Default value of $stdin.
STDOUT	Standard output stream. Default value of $stdout.
TOPLEVEL_BINDING	A Binding object at Ruby's top level.