Some of the pre-defined global variables have synonyms that are available via module Engish. For each of those, the English synonym is given.
To use the module:
require 'English'
Contains the Exception object set by Kernel#raise:
begin raise RuntimeError.new('Boo!') rescue RuntimeError p $! end
Output:
#<RuntimeError: Boo!>
English - $ERROR_INFO
Same as $!.backtrace; returns an array of backtrace positions:
begin raise RuntimeError.new('Boo!') rescue RuntimeError pp $@.take(4) end
Output:
["(irb):338:in `<top (required)>'", "/snap/ruby/317/lib/ruby/3.2.0/irb/workspace.rb:119:in `eval'", "/snap/ruby/317/lib/ruby/3.2.0/irb/workspace.rb:119:in `evaluate'", "/snap/ruby/317/lib/ruby/3.2.0/irb/context.rb:502:in `evaluate'"]
English - $ERROR_POSITION.
These global variables store information about the most recent successful match in the current scope.
For details and examples, see Regexp Global Variables.
MatchData object created from the match; thread-local and frame-local.
English - $LAST_MATCH_INFO.
The matched string.
English - $MATCH.
The string to the left of the match.
English - $PREMATCH.
The string to the right of the match.
English - $POSTMATCH.
The last group matched.
English - $LAST_PAREN_MATCH.
For $n the nth group of the match.
No English.
An input record separator, initially newline.
English - $INPUT_RECORD_SEPARATOR, $RS.
Aliased as $-0.
An input field separator, initially nil.
English - $FIELD_SEPARATOR, $FS.
Aliased as $-F.
An output record separator, initially nil.
English - $OUTPUT_RECORD_SEPARATOR, $ORS.
The current standard input stream; initially:
$stdin # => #<IO:<STDIN>>
The current standard output stream; initially:
$stdout # => #<IO:<STDOUT>>
The current standard error stream; initially:
$stderr # => #<IO:<STDERR>>
Points to stream ARGF if not empty, else to stream $stdin; read-only.
English - $DEFAULT_INPUT.
An output stream, initially $stdout.
English - <tt>$DEFAULT_OUTPUT
The input position (line number) in the most recently read stream.
English - $INPUT_LINE_NUMBER, $NR
The line (string) from the most recently read stream.
English - $LAST_READ_LINE.
Initially, contains the name of the script being executed; may be reassigned.
Points to ARGV.
English - $ARGV.
The process ID of the current process. Same as Process.pid.
English - $PROCESS_ID, $PID.
Initially nil, otherwise the Process::Status object created for the most-recently exited child process; thread-local.
English - $CHILD_STATUS.
Contains the array of paths to be searched by Kernel#load and Kernel#require.
Singleton method $LOAD_PATH.resolve_feature_path(feature) returns:
-
[:rb, path], wherepathis the path to the Ruby file to be loaded for the givenfeature. -
[:so+ path], wherepathis the path to the shared object file to be loaded for the givenfeature. -
nilif there is no suchfeatureandpath.
Examples:
$LOAD_PATH.resolve_feature_path('timeout') # => [:rb, "/snap/ruby/317/lib/ruby/3.2.0/timeout.rb"] $LOAD_PATH.resolve_feature_path('date_core') # => [:so, "/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/date_core.so"] $LOAD_PATH.resolve_feature_path('foo') # => nil
Aliased as $: and $-I.
Contains an array of the paths to the loaded files:
$LOADED_FEATURES.take(10) # => ["enumerator.so", "thread.rb", "fiber.so", "rational.so", "complex.so", "ruby2_keywords.rb", "/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/enc/encdb.so", "/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/enc/trans/transdb.so", "/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/rbconfig.rb", "/snap/ruby/317/lib/ruby/3.2.0/rubygems/compatibility.rb"]
Aliased as $".
The value returned by method ARGF.filename.
Initially true if command-line option -d or --debug is given, otherwise initially false; may be set to either value in the running program.
When true, prints each raised exception to $stderr.
Aliased as $-d.
Initially true if command-line option -v or -w is given, otherwise initially false; may be set to either value, or to nil, in the running program.
When true, enables Ruby warnings.
When nil, disables warnings, including those from Kernel#warn.
Aliased as $-v and $-w.
Whether command-line option -a was given; read-only.
Contains the extension given with command-line option -i, or nil if none.
An alias of ARGF.inplace_mode.
Whether command-line option -l was set; read-only.
Whether command-line option -p was given; read-only.
The standard input stream (the default value for $stdin):
STDIN # => #<IO:<STDIN>>
The standard output stream (the default value for $stdout):
STDOUT # => #<IO:<STDOUT>>
The standard error stream (the default value for $stderr):
STDERR # => #<IO:<STDERR>>
A hash of the contains current environment variables names and values:
ENV.take(5) # => [["COLORTERM", "truecolor"], ["DBUS_SESSION_BUS_ADDRESS", "unix:path=/run/user/1000/bus"], ["DESKTOP_SESSION", "ubuntu"], ["DISPLAY", ":0"], ["GDMSESSION", "ubuntu"]]
The virtual concatenation of the files given on the command line, or from $stdin if no files were given, "-" is given, or after all files have been read.
An array of the given command-line arguments.
The Binding of the top level scope:
TOPLEVEL_BINDING # => #<Binding:0x00007f58da0da7c0>
The Ruby version:
RUBY_VERSION # => "3.2.2"
The release date string:
RUBY_RELEASE_DATE # => "2023-03-30"
The platform identifier:
RUBY_PLATFORM # => "x86_64-linux"
The integer patch level for this Ruby:
RUBY_PATCHLEVEL # => 53
For a development build the patch level will be -1.
The git commit hash for this Ruby:
RUBY_REVISION # => "e51014f9c05aa65cbf203442d37fef7c12390015"
The copyright string:
RUBY_COPYRIGHT # => "ruby - Copyright (C) 1993-2023 Yukihiro Matsumoto"
The name of the Ruby implementation:
RUBY_ENGINE # => "ruby"
The version of the Ruby implementation:
RUBY_ENGINE_VERSION # => "3.2.2"
The description of the Ruby implementation:
RUBY_DESCRIPTION # => "ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]"
Defined if and only if the program has this line:
__END__
When defined, DATA is a File object containing the lines following the __END__, positioned at the first of those lines:
p DATA DATA.each_line { |line| p line } __END__
Output:
#<File:t.rb> "Foo\n" "Bar\n" "Baz\n"