Predefined Global Constants
TRUE
, FALSE
, and
NIL
are backward-compatible. It’s preferable
to use true
, false
, and
nil
.
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, e.g.,
i686-linux
.RUBY_RELEASE_DATE
A string indicating the release date of the Ruby interpreter, e.g.,
2001-09-19
.RUBY_VERSION
A string indicating the version of the Ruby interpreter, e.g.,
1.6.5
.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.
Get Ruby in a Nutshell now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.