Vim and grep regular expression similarities and differences

Regular expressions consist of two basic character types: literal (normal) text characters and metacharacters. Metacharacters enable regular expressions to have processing power. A meta-character is a special character in a regular expression that can be used to specify its leading character (that is, the character in front of the metacharacters) in the target object.

Vim Meta-character	grep Meta-character	Description
^	^	Match the starting position of the input string
$	$	Match the starting position of the input string
*	*	Matches the preceding subexpression 0 or n times (n>0)
\+	\+	Matches the preceding subexpression 1 or n times (n>1)
\?	\?	Match previous subexpression 0 or 1 times
\{n}	\{n\}	Match determined N Times (n>=0)
\{n,}	\{n,\}	Minimum match n times (∞>n>=0)
\{N,M}	\{n,m\}	Match at least n times and up to M (n<m)
\<	\<	Match the first words of the word
\>	\>	Match word endings
|		or characters, such as: X|y match x or Y
[ABC]	[ABC]	The character set is combined. Match any one of the characters contained
[^ABC]	[^ABC]	Represents any character that matches a character other than the characters in square brackets.
[A-z]	[A-z]	Character range, matching A-Z any character
[^a-z]	[^a-z]	Represents any character that matches a A-Z character except in square brackets.
\d	-----------	Matches a numeric character. equivalent to [0-9]
\d	-----------	Match non-numeric characters
\w	\w	Match 0-9,a-z,a-z
\w	\w	Match non-0-9,a-z,a-z

Vim and grep regular expressions are similar and different