wilbys / lfcs_notes

lfcs_notes

Regular Expressions

Character	Definition	Example	Result
^	Start of a string	^abc	abc, abcd, abc1
$	End of a string	abc$	abc, rasabc, 2aabc
.	Any character except newline	a.c	abc, acc, a1c
		Alteration	a
{...}	Explicit quantity of preceding character	ab{2}c	abbc
[...]	Explicit set of characters to match	a[bB]c	abc,aBc
[a-z0-9]	One lower case characters or number	a[a-z0-9]c	aac,a1c
(...)	Group of characters	(abc){2}	abcabc
*	Null or more of the preceding characters	a*bc	bc, abc, aabc, aaaabc
+	One or more of the preceding character	a+bc	abc, aabc
?	Null or one of the preceding character	a?bc	bc, abc
^$	Empty string

• Not all regular expressions are supported by grep. As alternative can be used egrep