7. Operators
	~	match regular expression		|| logical OR
	!~	don't match regular expression		&& logical AND
	<	less than				!  logical NOT
	<=	less than or equal
	>	greater than				+  addition
	>=	greater than or equal			-  subtraction
	!=	not identical to			/  division
	==	identical to				*  multiplication
	' '	concatenate				%  remainder

        compound assignments:
	+=	compound add (x = x + n)		++ autoincrement
	-=	compound subtract (x = x - n)		-- autodecrement
	*=	compound multiply (x = x * n)
	/=	compound divide (x = x / n)   sub in array is subscript in array?
	%=	compound remainder (x = x % n)

8. Built-in variables

	$n		field number n on each line
	$0		the entire line of input
	FILENAME	name of the current file being read
	NR		Number of Records (lines) read so far
	FNR		Record number in the current file
	NF		Number of Fields in the current Record (line)
	
	RS		Input Record separator
	FS		Input Field separator	
	ORS		Output Record separator
	OFS		Output Field separator
	OFMT		Output format for floating point numbers ( %.6g)

9. Built-in functions

	length(string)			returns the length of the string
	substr(string,st,k)		returns the substring of string
					  starting at position st and of
					  length k
	index(str1, str2)		returns the position of string str2
					  in str1.  If not found, returns 0
	sprintf(frmt, exprlist)		returns a string formatted according
					  to the format frmt using values in
					  the exprlist
	int(num)			returns the truncated integer value
					  of num
	cos(x)				returns the cosine of x (in radians)
	sin(x)				returns the sine of x
	atan(y,x)			returns the arctangent of y/x
	log(x)				returns natural log of x
	exp(x)				returns exponential e to the x
	sqrt(x)				returns the square root of x
	rand()				returns random number 0<=r<1
	srand([x])			uses x as a new seed for rand
	system("unix command")		execute a unix command in a subshell
	function name(param[,param]...) { [statement] ... } 
					defines a function
					    wherever a pattern
					    action pair goes.

Questions? Robert Katz: katz@ned.highline.edu
Last Update April 7, 2005