Escaping:
\char escape that particular char
For instance to specify special characters.. [].()\ etc.
Text:
. Any single character (on its own = the entire URI)
[chars] Character class: One of following chars
[^chars] Character class: None of following chars
text1|text2 Alternative: text1 or text2 (i.e. "or")
e.g. [^/] matches any character except /
(foo|bar)\.html matches foo.html and bar.html
Quantifiers:
? 0 or 1 of the preceding text
* 0 or N of the preceding text (hungry)
+ 1 or N of the preceding text
e.g. (.+)\.html? matches foo.htm and foo.html
(foo)?bar\.html matches bar.html and foobar.html
Grouping:
(text) Grouping of text
Either to set the borders of an alternative or
for making backreferences where the nth group can
be used on the target of a RewriteRule with $n
e.g. ^(.*)\.html foo.php?bar=$1
Anchors:
^ Start of line anchor
$ End of line anchor
An anchor explicitly states that the character right next to it MUST
be either the very first character ("^"), or the very last character ("$")
of the URI string to match against the pattern, e.g..
^foo(.*) matches foo and foobar but not eggfoo
(.*)l$ matches fool and cool, but not foo
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