Regular Expression Metacharacters

Character

Definition

. (dot)

Any one character

[...] [.-.]

Any one of the characters within the square brackets or within range

[^...]

Any one of the characters not within the square brackets

^

Start of line

$

End of line

\<

Start of word

/>

End of word

| (vertical bar)

Separates two expressions, matches either

?

Previous character (or group) is optional

+

One or more of the previous character (or group)

*

Any number (including none) of the previous character (or group) NOTE: Matches as many as possible

( )

Three uses:
1: Used to enclose a pair of expressions, separated by | (vertical bar - see above)
2: Grouping for quantifiers ('?', '+', and '*' - see above)
3: Carry some text that matches the expression within (see '\1', etc, below)

\1 (and \2, \3, etc)

Output the text 'carried forward' by the brackets (see '( )' above).

\ (backward slant)

Escape character except when as used above.
The character that immediately follows a \ will be interpreted as a literal.