RegExp Cheat Page

Regular Expression Basics
.Any character except newline
aThe character a
abThe string ab
a|ba or b
a*0 or more a's
\Escapes a special character
Regular Expression Quantifiers
*0 or more
+1 or more
?0 or 1
{2}Exactly 2
{2, 5}Between 2 and 5
{2,}2 or more
Default is greedy. Append ? for reluctant.
Regular Expression Groups
(...)Capturing group
(?:...)Non-capturing group
\YMatch the Y'th captured group
Regular Expression Character Classes
[ab-d]One character of: a, b, c, d
[^ab-d]One character except: a, b, c, d
[\b]Backspace character
\dOne digit
\DOne non-digit
\sOne whitespace
\SOne non-whitespace
\wOne word character
\WOne non-word character
Regular Expression Assertions
^Start of string
$End of string
\bWord boundary
\BNon-word boundary
(?=...)Positive lookahead
(?!...)Negative lookahead
Regular Expression Flags
gGlobal Match
iIgnore case
m^ and $ match start and end of line
Regular Expression Special Characters
\nNewline
\rCarriage return
\tTab
\0Null character
\YYYOctal character YYY
\xYYHexadecimal character YY
\uYYYYHexadecimal character YYYY
\cYControl character Y
Regular Expression Posix Classes
Regular Expression Replacement
$$Inserts $
$&Insert entire match
$`Insert preceding string
$'Insert following string
$YInsert Y'th captured group