Ruby is an interpreted scripting language for quick and easy
object-oriented programming. It has many features to process text
files and to do system management tasks (as in Perl). It is simple,
straight-forward, and extensible.
If you want a language for easy object-oriented programming, or you
don't like the Perl ugliness, or you do like the concept of LISP, but
don't like too much parentheses, Ruby may be the language of your
Ruby's features are as follows:
Ruby is an interpreted language, so you don't have to recompile
programs written in Ruby to execute them.
Variables have no type (dynamic typing)
Variables in Ruby can contain data of any type. You don't have to
worry about variable typing. Consequently, it has a weaker compile
No declaration needed
You can use variables in your Ruby programs without any declarations.
Variable names denote their scope, local, global, instance, etc.
Ruby has a simple syntax influenced slightly from Eiffel.
No user-level memory management
Ruby has automatic memory management. Objects no longer referenced
from anywhere are automatically collected by the garbage collector
built into the interpreter.
Everything is an object
Ruby is the purely object-oriented language, and was so since its
creation. Even such basic data as integers are seen as objects.
Class, inheritance, and methods
Of course, as an object-oriented language, Ruby has such basic
features like classes, inheritance, and methods.
Ruby has the ability to define methods for certain objects. For
example, you can define a press-button action for certain widget by
defining a singleton method for the button. Or, you can make up your
own prototype based object system using singleton methods, if you want
Mix-in by modules
Ruby intentionally does not have the multiple inheritance as it is a
source of confusion. Instead, Ruby has the ability to share
implementations across the inheritance tree. This is often called
Ruby has iterators for loop abstraction.
In Ruby, you can objectify the procedure.
Text processing and regular expression
Ruby has a bunch of text processing features like in Perl.
With built-in bignums, you can for example calculate factorial(400).
As in Java(tm).
Direct access to the OS
Ruby can use most
system calls, often used in system programming.
systems, you can load object files into the Ruby interpreter
Ruby interpreter accepts following command-line options (switches).
They are quite similar to those of
Prints the copyright notice.
Prints the version of Ruby interpreter.
Specifies the input record separator
as an octal number. If no digit is given, the null character is taken
as the separator. Other switches may follow the digits.
turns Ruby into paragraph mode.
makes Ruby read whole file at once as a single string since there is
no legal character with that value.
Causes Ruby to switch to the directory.
Specifies input field separator
Used to tell Ruby where to load the library scripts. Directory path
will be added to the load-path variable
Specifies KANJI (Japanese) encoding.
Makes Ruby use the
environment variable to search for script, unless if its name begins
with a slash. This is used to emulate
on machines that don't support it, in the following manner:
# This line makes the next one a comment in Ruby \
exec /usr/local/bin/ruby -S $0 $*
Turns on taint checks at the specified level (default 1).
Turns on auto-split mode when used with
In auto-split mode, Ruby executes
$F = $_.split
at beginning of each loop.
Causes Ruby to check the syntax of the script and exit without
executing. If there are no syntax errors, Ruby will print
to the standard output.
Turns on debug mode.
will be set to true.
Specifies script from command-line while telling Ruby not to search
the rest of arguments for a script file name.
Prints a summary of the options.
Specifies in-place-edit mode. The extension, if specified, is added
to old file name to make a backup copy. For example:
Causes Ruby to load the library using require. It is useful when using
Enables some switch parsing for switches after script name but before
any file name arguments (or before a
Any switches found there are removed from
and set the corresponding variable in the script. For example:
#! /usr/local/bin/ruby -s
# prints "true" if invoked with `-xyz' switch.
print "true\n" if $xyz
On some systems
does not always contain the full pathname, so you need the
switch to tell Ruby to search for the script if necessary. To handle
embedded spaces or such. A better construct than
but it does not work if the script is being interpreted by
Enables verbose mode. Ruby will print its version at the beginning,
and set the variable
to true. Some methods print extra messages if this variable is true.
If this switch is given, and no other switches are present, Ruby quits
after printing its version.
Enables verbose mode without printing version message at the
beginning. It sets the
variable to true.
Tells Ruby that the script is embedded in a message. Leading garbage
will be discarded until the first that starts with
and contains the string,
Any meaningful switches on that line will applied. The end of script
must be specified with either
or reserved word
If the directory name is specified, Ruby will switch to that directory
before executing script.
Turns on compiler debug mode. Ruby will print a bunch of internal
state messages during compiling scripts. You don't have to specify
this switch, unless you are going to debug the Ruby interpreter.
A colon-separated list of directories that are added to Ruby's
library load path
("$:"). Directories from this environment variable are searched
before the standard load path is searched.
Additional Ruby options.
A colon-separated list of directories that Ruby searches for
Ruby programs when the
flag is specified. This variable precedes the
The path to the system shell command. This environment variable is
enabled for only mswin32, mingw32, and OS/2 platforms. If this
variable is not defined, Ruby refers to
Ruby refers to the
environment variable on calling Kernel#system.
This variable is obsolete.
Ruby is designed and implemented by
Yukihiro Matsumoto <firstname.lastname@example.org>.