jooeycheng/ruby_dollar_signs.txt

## ruby_dollar_signs.txt
$: (Dollar Colon)          is basically a shorthand version of $LOAD_PATH.
                           contains an array of paths that your script will search through when using require.
$0 (Dollar Zero)           contains the name of the ruby program being run. This is typically the script name.
$* (Dollar Splat)          is basically shorthand for ARGV. $* contains the command line arguments that were passed to the script.
$? (Dollar Question Mark)  returns the exit status of the last child process to finish.
$$ (Dollar Dollar)         returns the process number of the program currently being ran.
$~ (Dollar Tilde)          contains the MatchData from the previous successful pattern match.
$1, $2, $3, $4 etc         represent the content of the previous successful pattern match.
$& (Dollar Ampersand)      contains the matched string from the previous successful pattern match.
$+ (Dollar Plus)           contains the last match from the previous successful pattern match.
$` (Dollar Backtick)       contains the string before the actual matched string of the previous successful pattern match.
$’ (Dollar Apostrophe)     contains the string after the actual matched string of the previous successful pattern match.
$! (Dollar Bang)           contains the Exception that was passed to raise.
$@ (Dollar At Symbol)      contains the backtrace for the last Exception raised.

Alternate Explaination (from diff site)
$!	latest error message
$@	location of error
$_	string last read by gets
$.	line number last read by interpreter
$&	string last matched by regexp
$~	the last regexp match, as an array of subexpressions
$n	the nth subexpression in the last match (same as $~[n])
$=	case-insensitivity flag
$/	input record separator
$\	output record separator
$0	the name of the ruby script file
$*	the command line arguments
$$	interpreter's process ID
$?	exit status of last executed child process
	$: (Dollar Colon) is basically a shorthand version of $LOAD_PATH.
	contains an array of paths that your script will search through when using require.
	$0 (Dollar Zero) contains the name of the ruby program being run. This is typically the script name.
	$* (Dollar Splat) is basically shorthand for ARGV. $* contains the command line arguments that were passed to the script.
	$? (Dollar Question Mark) returns the exit status of the last child process to finish.
	$$ (Dollar Dollar) returns the process number of the program currently being ran.
	$~ (Dollar Tilde) contains the MatchData from the previous successful pattern match.
	$1, $2, $3, $4 etc represent the content of the previous successful pattern match.
	$& (Dollar Ampersand) contains the matched string from the previous successful pattern match.
	$+ (Dollar Plus) contains the last match from the previous successful pattern match.
	$` (Dollar Backtick) contains the string before the actual matched string of the previous successful pattern match.
	$’ (Dollar Apostrophe) contains the string after the actual matched string of the previous successful pattern match.
	$! (Dollar Bang) contains the Exception that was passed to raise.
	$@ (Dollar At Symbol) contains the backtrace for the last Exception raised.

	Alternate Explaination (from diff site)
	$! latest error message
	$@ location of error
	$_ string last read by gets
	$. line number last read by interpreter
	$& string last matched by regexp
	$~ the last regexp match, as an array of subexpressions
	$n the nth subexpression in the last match (same as $~[n])
	$= case-insensitivity flag
	$/ input record separator
	$\ output record separator
	$0 the name of the ruby script file
	$* the command line arguments
	$$ interpreter's process ID
	$? exit status of last executed child process