cyber-security-resources/cheat_sheets/regular-expressions.md

Regular Expression Cheat Sheets and Resources

• Regular Expression Cheat Sheet
• Quick-Start: Regex Cheat Sheet
• RegexR - Generate Regular Expressions
• RegexOne Exercises
• Regex Crossword
• Regex101

Quick Regex Reference

Character	Meaning	Example
*	Match zero, one or more of the previous	Ah* matches "Ahhhhh" or "A"
?	Match zero or one of the previous	Ah? matches "Al" or "Ah"
+	Match one or more of the previous	Ah+ matches "Ah" or "Ahhh" but not "A"
\	Used to escape a special character	Hungry\? matches "Hungry?"
.	Wildcard character, matches any character	do.* matches "dog", "door", "dot", etc.
( )	Group characters	See example for |
[ ]	Matches a range of characters	[cbf]ar matches "car", "bar", or "far" [0-9]+ matches any positive integer [a-zA-Z] matches ascii letters a-z (uppercase and lower case) [^0-9] matches any character not 0-9.
|	Matche previous OR next character/group	(Mon|Tues)day matches "Monday" or "Tuesday"
{ }	Matches a specified number of occurrences of the previous	[0-9]{3} matches "315" but not "31" [0-9]{2,4} matches "12", "123", and "1234" [0-9]{2,} matches "1234567..."
^	Beginning of a string. Or within a character range [] negation.	^http matches strings that begin with http, such as a url. [^0-9] matches any character not 0-9.
$	End of a string.	ing$ matches "exciting" but not "ingenious"