Regular expression fog, regular expression syntax Comparison among Various tools

In a variety of commonly used tools, regular expressions are similar but different. The following table lists some common regular expressions and their differences. There are always many projects and many omissions are required. please point out the missing items. The perl regular expression is used as the benchmark, and different usages are marked in pink. Grep2.5.1egrep2.5.1sed3.02sed4.07awk3.1.1perl5.8 regular expression

Among various commonly used tools,
Regular expressions are similar but different.
The following table lists some common regular expressions and their differences.
There are always many projects and many omissions are required. please point out the missing items.
The perl regular expression is used as the benchmark, and different usages are marked in pink.

	Grep 2.5.1	Egrep 2.5.1	Sed 3.02 Sed 4.07	Awk 3.1.1	Perl 5.8.0	Vim 1, 6.1	JavaScript ??
Escape	\	\	\	\	\	\	\
Line Header	^	^	^	^	^	^	^
End of line	$	$	$	$	$	$	$
N	\		\	Or \ only define -- posix or -- re-interval valid (to express} and not define -- posix or -- re-interval, the syntax is not used, \} \ {synonymous		\
	*	*	*	* Or \ *, (to express *, use \\*)	*	*	*
	\ +	+	\ +	+ Or \ +, (to express +, use \ +)	+	\ +	+
	\?	?	\?	? Or \?, (To express ?, Use \\?)	?	\?	?
Any character	.	.	.	. Contains \ n.	./S after modification, \ n is included	. Division \ n	. Division \ n
(Pat) match and obtain results	\ (Pat \)	(Pat)	\ (Pat \)	(Pat) or \ (pat \) (to express parentheses, use \\(\\))	(Pat)	\ (Pat \)	(Pat)
(? : Pat) matched but not returned	Not supported	Not supported	Not supported	Not supported	(? : Pat)	Not supported	(? : Pat)
(? = Pat) equal to pre-query	Not supported	Not supported	Not supported	Not supported	(? = Pat)	Not supported	(? = Pat)
(?! Pat) unprecheck	Not supported	Not supported	Not supported	Not supported	(?! Pat)	Not supported	(?! Pat)
| Or	\ |	|	\ |	| Or \ | (to express |, use \ |)	|	\ |	|
Any character	[Xyz]	[Xyz]	[Xyz]	[Xyz]	[Xyz]	[Xyz]	[Xyz]
[. Ch.] [= ch =]	Not supported	Not supported	[. Ch.]	Not supported	Not supported	Not supported	Not supported
Word boundary \ B	\ B	\ B	\ B	Not supported	\ B	Not supported	\ B
Non-word boundary \ B	\ B	\ B	\ B	Not supported	\ B	Not supported	\ B
Left and right boundary of words <>	\ <\>	\ <\>	\ <\>	Not supported (> <和\> \ <和\\> \\ <同义< td>	Not supported (> <和\> \ <同义< td>	\ <\>	Not supported (> <和\> \ <同义< td>
Control character/cx	Not supported	Not supported	\ Cx	Not supported	\ Cx	Not supported	\ Cx
Number \ d	Not supported	Not supported	Not supported	Not supported	\ D	\ D	\ D
Non-digit \ D	Not supported	Not supported	Not supported	Not supported	\ D	\ D	\ D
Form Feed \ f	Not supported	Not supported	High version support	\ F	\ F	Other meanings \ f indicates the file name characters	\ F
Newline \ n	Not supported	Not supported	Not supported	\ N	\ N	\ N	\ N
Press enter \ r	Not supported	Not supported	\ R	\ R	\ R	\ R	\ R
Blank \ s	Not supported	Not supported	Not supported	Not supported	\ S	\ S	\ S
Non-blank \ S	Not supported	Not supported	Not supported	Not supported	\ S	\ S	\ S
Tab \ t	Not supported	Not supported	High version support	\ T	\ T	\ T	\ T
Vertical Tab \ v	Not supported	Not supported	High version support	\ V	\ V	Very magic	\ V
Word character \ w [A-Za-z0-9 _]	\ W	\ W	\ W	Not supported	\ W	\ W	\ W
Non-word character \ W [^ A-Za-z0-9]	\ W	\ W	\ W	Not supported	\ W	\ W	\ W
\ Xn hexadecimal	Not supported	Not supported	High version support	\ Xn	\ Xn	Also, \ x indicates [0-9A-Za-z]	\ Xn
\ N octal	Not supported	Not supported	Not supported	\ N	\ N	Not supported	\ N
\ N back reference	\ N	\ N	\ N	\ N is available only for the result.	\ N	\ N is available only for the result.	\ N
[: Alnum:] letters and numbers	[: Alnum:]	[: Alnum:]	[: Alnum:]	[: Alnum:]	[: Alnum:]	[: Alnum:]	Not supported
[: Alpha:] Letters	[: Alpha:]	[: Alpha:]	[: Alpha:]	[: Alpha:]	[: Alpha:]	[: Alpha:]	Not supported
[: Cntrl:] control characters	[: Cntrl:]	[: Cntrl:]	[: Cntrl:]	[: Cntrl:]	[: Cntrl:]	[: Cntrl:]	Not supported
[: Digit:] number	[: Digit:]	[: Digit:]	[: Digit:]	[: Digit:]	[: Digit:]	[: Digit:]	Not supported
[: Graph:] printable characters (excluding spaces)	[: Graph:]	[: Graph:]	[: Graph:]	[: Graph:]	[: Graph:]	[: Graph:]	Not supported
[: Lower:] lower case	[: Lower:]	[: Lower:]	[: Lower:]	[: Lower:]	[: Lower:]	[: Lower:]	Not supported
[: Print:] printable characters (including spaces)	[: Print:]	[: Print:]	[: Print:]	[: Print:]	[: Print:]	[: Print:]	Not supported
[: Punct:] punctuation	[: Punct:]	[: Punct:]	[: Punct:]	[: Punct:]	[: Punct:]	[: Punct:]	Not supported
[: Space:] space	[: Space:]	[: Space:]	[: Space:]	[: Space:]	[: Space:]	[: Space:]	Not supported
[: Upper:] uppercase letters	[: Upper:]	[: Upper:]	[: Upper:]	[: Upper:]	[: Upper:]	[: Upper:]	Not supported
[: Xdigit:] hexadecimal number	[: Xdigit:]	[: Xdigit:]	[: Xdigit:]	[: Xdigit:]	[: Xdigit:]	[: Xdigit:]	Not supported
[: Return:]	Not supported	Not supported	Not supported	Not supported	Not supported	[: Return:]	Not supported
[: Tab:]	Not supported	Not supported	Not supported	Not supported	Not supported	[: Tab:]	Not supported
[: Escape:]	Not supported	Not supported	Not supported	Not supported	Not supported	[: Escape:]	Not supported
[: Backspace:]	Not supported	Not supported	Not supported	Not supported	Not supported	[: Backspace:]	Not supported