text 21 Dec Ruby pre-defined variables

  • $! The exception information message set by ‘raise’.
  • $@ Array of backtrace of the last exception thrown.
  • $& The string matched by the last successful match.
  • $` The string to the left of the last successful match.
  • $' The string to the right of the last successful match.
  • $+ The highest group matched by the last successful match.
  • $1 The Nth group of the last successful match. May be > 1.
  • $~ The information about the last match in the current scope.
  • $= The flag for case insensitive, nil by default.
  • $/ The input record separator, newline by default.
  • $\ The output record separator for the print and IO#write. Default is nil.
  • $, The output field separator for the print and Array#join.
  • $; The default separator for String#split.
  • $. The current input line number of the last file that was read.
  • $< The virtual concatenation file of the files given on command line (or from $stdin if no files were given).
  • $> The default output for print, printf. $stdout by default.
  • $_ The last input line of string by gets or readline.
  • $0 Contains the name of the script being executed. May be assignable.
  • $* Command line arguments given for the script sans args.
  • $$ The process number of the Ruby running this script.
  • $? The status of the last executed child process.
  • $: Load path for scripts and binary modules by load or require.
  • $" The array contains the module names loaded by require.
  • $DEBUG The status of the -d switch.
  • $FILENAME Current input file from $<. Same as $<.filename.
  • $LOAD_PATH The alias to the $:.
  • $stderr The current standard error output.
  • $stdin The current standard input.
  • $stdout The current standard output.
  • $VERBOSE The verbose flag, which is set by the -v switch.
  • $-0 The alias to $/.
  • $-a True if option -a is set. Read-only variable.
  • $-d The alias to $DEBUG.
  • $-F The alias to $;.
  • $-i In in-place-edit mode, this variable holds the extension, otherwise nil.
  • $-I The alias to $:.
  • $-l True if option -l is set. Read-only variable.
  • $-p True if option -p is set. Read-only variable.
  • $-v The alias to $VERBOSE.
  • $-w True if option -w is set.

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