Regular Expressions

^
Beginning of input or line
^T matches "T" in "This good earth" but not in "Uncle Tom's Cabin"
---

$
End of input or line
h$ matches "h" in "teach" but not in "teacher"
---

*
The preceding character 0 or more times
um* matches "um" in "rum", "umm" in "yummy", and "u" in "huge"
---

+
The preceding character 1 or more times
um+ matches "um" in "rum" and "umm" in "yummy" but nothing in "huge"
---

?
The preceding character at most once (that is, indicates that the preceding character is optional)
st?on matches "son" in "Johnson" and "ston" in "Johnston" but nothing in "Appleton" or "tension"
---

.
Any single character except newline
.an matches "ran" and "can" in the phrase "bran muffins can be tasty"
---

Xy
Either x or y
FF00000000FF matches "FF0000" in bgcolor="#FF0000" and "0000FF’" in font color="#0000FF"
---

{n}
Exactly n occurrences of the preceding character
o{2} matches "oo" in "loom" and the first two o's in "mooooo" but nothing in "money"
---

{n,m}
At least n, and at most m, occurrences of the preceding character
F{2,4} matches "FF" in "#FF0000" and the first four F’s in #FFFFFF

[abc]
Any one of the characters enclosed in the brackets. Specify a range of characters with a hyphen (for example, [a-f] is equivalent to [abcdef]).
[e-g] matches "e" in "bed", "f" in "folly", and "g" in "guard"
---

[^abc]
Any character not enclosed in the brackets. Specify a range of characters with a hyphen (for example, [^a-f] is equivalent to [^abcdef]).
[^aeiou] initially matches "r" in "orange", "b" in "book", and "k" in "eek!"
---

\b
A word boundary (such as a space or carriage return).
\bb matches "b" in "book" but nothing in "goober" or "snob"
---

\B
Anything other than a word boundary.
\Bb matches "b" in "goober" but nothing in "book"
---

\d
Any digit character. Equivalent to [0-9].
\d matches "3" in "C3PO" and "2" in "apartment 2G"
---

\D
Any nondigit character. Equivalent to [^0-9].
\D matches "S" in "900S" and "Q" in "Q45"
---

\w
Any alphanumeric character, including underscore. Equivalent to [A-Za-z0-9_].
b\w* matches "barking" in "the barking dog" and both "big" and "black" in "the big black dog"
---

\W
Any non-alphanumeric character. Equivalent to [^A-Za-z0-9_].
\W matches "&" in "Jake&Mattie" and "%" in "100%"
---

\s
Any single white-space character, including space, tab, form feed, or line feed.
\sbook matches "book" in "blue book" but nothing in "notebook"
---

\S
Any single non–white-space character.
\Sbook matches "book" in "notebook" but nothing in "blue book"
---

\f
A form feed character.
---

\n
A line feed character.
---

\r
A carriage return character.
---

\t
A tab character.
---

official web: http://www.adobe.com/devnet/dreamweaver/articles/regular_expressions_03.html