gistfile1

$!          # 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.