зеркало из https://github.com/github/ruby.git
423 строки
8.5 KiB
Plaintext
423 строки
8.5 KiB
Plaintext
= Pre-Defined Global Variables
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Some of the pre-defined global variables have synonyms
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that are available via module English.
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For each of those, the \English synonym is given.
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To use the module:
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require 'English'
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== Exceptions
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=== <tt>$!</tt> (\Exception)
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Contains the Exception object set by Kernel#raise:
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begin
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raise RuntimeError.new('Boo!')
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rescue RuntimeError
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p $!
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end
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Output:
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#<RuntimeError: Boo!>
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English - <tt>$ERROR_INFO</tt>
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=== <tt>$@</tt> (Backtrace)
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Same as <tt>$!.backtrace</tt>;
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returns an array of backtrace positions:
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begin
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raise RuntimeError.new('Boo!')
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rescue RuntimeError
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pp $@.take(4)
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end
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Output:
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["(irb):338:in `<top (required)>'",
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"/snap/ruby/317/lib/ruby/3.2.0/irb/workspace.rb:119:in `eval'",
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"/snap/ruby/317/lib/ruby/3.2.0/irb/workspace.rb:119:in `evaluate'",
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"/snap/ruby/317/lib/ruby/3.2.0/irb/context.rb:502:in `evaluate'"]
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English - <tt>$ERROR_POSITION</tt>.
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== Pattern Matching
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These global variables store information about the most recent
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successful match in the current scope.
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For details and examples,
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see {Regexp Global Variables}[rdoc-ref:Regexp@Global+Variables].
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=== <tt>$~</tt> (\MatchData)
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MatchData object created from the match;
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thread-local and frame-local.
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English - <tt>$LAST_MATCH_INFO</tt>.
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=== <tt>$&</tt> (Matched Substring)
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The matched string.
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English - <tt>$MATCH</tt>.
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=== <tt>$`</tt> (Pre-Match Substring)
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The string to the left of the match.
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English - <tt>$PREMATCH</tt>.
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=== <tt>$'</tt> (Post-Match Substring)
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The string to the right of the match.
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English - <tt>$POSTMATCH</tt>.
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=== <tt>$+</tt> (Last Matched Group)
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The last group matched.
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English - <tt>$LAST_PAREN_MATCH</tt>.
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=== <tt>$1</tt>, <tt>$2</tt>, \Etc. (Matched Group)
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For <tt>$_n_</tt> the _nth_ group of the match.
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No \English.
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== Separators
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=== <tt>$/</tt> (Input Record Separator)
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An input record separator, initially newline.
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English - <tt>$INPUT_RECORD_SEPARATOR</tt>, <tt>$RS</tt>.
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Aliased as <tt>$-0</tt>.
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=== <tt>$;</tt> (Input Field Separator)
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An input field separator, initially +nil+.
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English - <tt>$FIELD_SEPARATOR</tt>, <tt>$FS</tt>.
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Aliased as <tt>$-F</tt>.
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=== <tt>$\\</tt> (Output Record Separator)
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An output record separator, initially +nil+.
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English - <tt>$OUTPUT_RECORD_SEPARATOR</tt>, <tt>$ORS</tt>.
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== Streams
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=== <tt>$stdin</tt> (Standard Input)
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The current standard input stream; initially:
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$stdin # => #<IO:<STDIN>>
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=== <tt>$stdout</tt> (Standard Output)
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The current standard output stream; initially:
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$stdout # => #<IO:<STDOUT>>
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=== <tt>$stderr</tt> (Standard Error)
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The current standard error stream; initially:
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$stderr # => #<IO:<STDERR>>
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=== <tt>$<</tt> (\ARGF or $stdin)
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Points to stream ARGF if not empty, else to stream $stdin; read-only.
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English - <tt>$DEFAULT_INPUT</tt>.
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=== <tt>$></tt> (Default Standard Output)
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An output stream, initially <tt>$stdout</tt>.
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English - <tt>$DEFAULT_OUTPUT
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=== <tt>$.</tt> (Input Position)
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The input position (line number) in the most recently read stream.
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English - <tt>$INPUT_LINE_NUMBER</tt>, <tt>$NR</tt>
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=== <tt>$_</tt> (Last Read Line)
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The line (string) from the most recently read stream.
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English - <tt>$LAST_READ_LINE</tt>.
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== Processes
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=== <tt>$0</tt>
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Initially, contains the name of the script being executed;
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may be reassigned.
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=== <tt>$*</tt> (\ARGV)
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Points to ARGV.
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English - <tt>$ARGV</tt>.
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=== <tt>$$</tt> (Process ID)
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The process ID of the current process. Same as Process.pid.
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English - <tt>$PROCESS_ID</tt>, <tt>$PID</tt>.
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=== <tt>$?</tt> (Child Status)
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Initially +nil+, otherwise the Process::Status object
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created for the most-recently exited child process;
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thread-local.
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English - <tt>$CHILD_STATUS</tt>.
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=== <tt>$LOAD_PATH</tt> (Load Path)
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Contains the array of paths to be searched
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by Kernel#load and Kernel#require.
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Singleton method <tt>$LOAD_PATH.resolve_feature_path(feature)</tt>
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returns:
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- <tt>[:rb, _path_]</tt>, where +path+ is the path to the Ruby file
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to be loaded for the given +feature+.
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- <tt>[:so+ _path_]</tt>, where +path+ is the path to the shared object file
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to be loaded for the given +feature+.
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- +nil+ if there is no such +feature+ and +path+.
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Examples:
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$LOAD_PATH.resolve_feature_path('timeout')
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# => [:rb, "/snap/ruby/317/lib/ruby/3.2.0/timeout.rb"]
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$LOAD_PATH.resolve_feature_path('date_core')
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# => [:so, "/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/date_core.so"]
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$LOAD_PATH.resolve_feature_path('foo')
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# => nil
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Aliased as <tt>$:</tt> and <tt>$-I</tt>.
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=== <tt>$LOADED_FEATURES</tt>
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Contains an array of the paths to the loaded files:
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$LOADED_FEATURES.take(10)
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# =>
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["enumerator.so",
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"thread.rb",
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"fiber.so",
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"rational.so",
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"complex.so",
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"ruby2_keywords.rb",
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"/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/enc/encdb.so",
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"/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/enc/trans/transdb.so",
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"/snap/ruby/317/lib/ruby/3.2.0/x86_64-linux/rbconfig.rb",
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"/snap/ruby/317/lib/ruby/3.2.0/rubygems/compatibility.rb"]
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Aliased as <tt>$"</tt>.
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== Debugging
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=== <tt>$FILENAME</tt>
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The value returned by method ARGF.filename.
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=== <tt>$DEBUG</tt>
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Initially +true+ if command-line option <tt>-d</tt> or <tt>--debug</tt> is given,
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otherwise initially +false+;
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may be set to either value in the running program.
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When +true+, prints each raised exception to <tt>$stderr</tt>.
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Aliased as <tt>$-d</tt>.
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=== <tt>$VERBOSE</tt>
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Initially +true+ if command-line option <tt>-v</tt> or <tt>-w</tt> is given,
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otherwise initially +false+;
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may be set to either value, or to +nil+, in the running program.
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When +true+, enables Ruby warnings.
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When +nil+, disables warnings, including those from Kernel#warn.
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Aliased as <tt>$-v</tt> and <tt>$-w</tt>.
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== Other Variables
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=== <tt>$-a</tt>
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Whether command-line option <tt>-a</tt> was given; read-only.
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=== <tt>$-i</tt>
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Contains the extension given with command-line option <tt>-i</tt>,
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or +nil+ if none.
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An alias of ARGF.inplace_mode.
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=== <tt>$-l</tt>
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Whether command-line option <tt>-l</tt> was set; read-only.
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=== <tt>$-p</tt>
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Whether command-line option <tt>-p</tt> was given; read-only.
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== Deprecated
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=== <tt>$=</tt>
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=== <tt>$,</tt>
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= Pre-Defined Global Constants
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= Streams
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=== <tt>STDIN</tt>
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The standard input stream (the default value for <tt>$stdin</tt>):
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STDIN # => #<IO:<STDIN>>
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=== <tt>STDOUT</tt>
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The standard output stream (the default value for <tt>$stdout</tt>):
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STDOUT # => #<IO:<STDOUT>>
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=== <tt>STDERR</tt>
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The standard error stream (the default value for <tt>$stderr</tt>):
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STDERR # => #<IO:<STDERR>>
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== Environment
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=== ENV
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A hash of the contains current environment variables names and values:
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ENV.take(5)
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# =>
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[["COLORTERM", "truecolor"],
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["DBUS_SESSION_BUS_ADDRESS", "unix:path=/run/user/1000/bus"],
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["DESKTOP_SESSION", "ubuntu"],
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["DISPLAY", ":0"],
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["GDMSESSION", "ubuntu"]]
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=== ARGF
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The virtual concatenation of the files given on the command line, or from
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<tt>$stdin</tt> if no files were given, <tt>"-"</tt> is given, or after
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all files have been read.
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=== <tt>ARGV</tt>
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An array of the given command-line arguments.
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=== <tt>TOPLEVEL_BINDING</tt>
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The Binding of the top level scope:
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TOPLEVEL_BINDING # => #<Binding:0x00007f58da0da7c0>
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=== <tt>RUBY_VERSION</tt>
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The Ruby version:
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RUBY_VERSION # => "3.2.2"
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=== <tt>RUBY_RELEASE_DATE</tt>
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The release date string:
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RUBY_RELEASE_DATE # => "2023-03-30"
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=== <tt>RUBY_PLATFORM</tt>
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The platform identifier:
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RUBY_PLATFORM # => "x86_64-linux"
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=== <tt>RUBY_PATCHLEVEL</tt>
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The integer patch level for this Ruby:
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RUBY_PATCHLEVEL # => 53
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For a development build the patch level will be -1.
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=== <tt>RUBY_REVISION</tt>
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The git commit hash for this Ruby:
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RUBY_REVISION # => "e51014f9c05aa65cbf203442d37fef7c12390015"
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=== <tt>RUBY_COPYRIGHT</tt>
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The copyright string:
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RUBY_COPYRIGHT
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# => "ruby - Copyright (C) 1993-2023 Yukihiro Matsumoto"
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=== <tt>RUBY_ENGINE</tt>
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The name of the Ruby implementation:
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RUBY_ENGINE # => "ruby"
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=== <tt>RUBY_ENGINE_VERSION</tt>
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The version of the Ruby implementation:
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RUBY_ENGINE_VERSION # => "3.2.2"
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=== <tt>RUBY_DESCRIPTION</tt>
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The description of the Ruby implementation:
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RUBY_DESCRIPTION
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# => "ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]"
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== Embedded \Data
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=== <tt>DATA</tt>
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Defined if and only if the program has this line:
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__END__
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When defined, <tt>DATA</tt> is a File object
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containing the lines following the <tt>__END__</tt>,
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positioned at the first of those lines:
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p DATA
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DATA.each_line { |line| p line }
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__END__
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Foo
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Bar
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Baz
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Output:
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#<File:t.rb>
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"Foo\n"
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"Bar\n"
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"Baz\n"
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