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A.7 Common Extensions Summary

The following table summarizes the common extensions supported by gawk, Brian Kernighan’s awk, and mawk, the three most widely used freely available versions of awk (see Other Freely Available awk Implementations).

Feature	BWK awk	mawk	gawk	Now standard
‘\x’ escape sequence	X	X	X
FS as null string	X	X	X
/dev/stdin special file	X	X	X
/dev/stdout special file	X	X	X
/dev/stderr special file	X	X	X
delete without subscript	X	X	X	X
fflush() function	X	X	X	X
length() of an array	X	X	X
nextfile statement	X	X	X	X
** and **= operators	X		X
func keyword	X		X
BINMODE variable		X	X
RS as regexp	X	X	X
Time-related functions		X	X