A regular character in
a regular expression matches the same character in the source string, and a sequence of such
characters matches the same sequence in the source string. This is similar to searching for substrings
in a string. For example, if you match ???or??? in ???favorite color???, you??™ll find two matches for it.
A regular expression can contain metacharacters, which have special properties, and it??™s
their power and flexibility that makes regular expressions so useful. For example, the question
mark (?) metacharacter specifies that the preceding character is optional. So if you want to
match ???color??? and ???colour???, your regular expression would be colou?r.
CHAPTER 7 ?– SEARCH ENGINE OPTIMIZATION 195
As pointed out earlier, regular expressions can become extremely complex when you get
into their more subtle details. In this section, you??™ll find explanations for the regular expressions
we??™re using, and we suggest that you continue your regex training using a specialized
book or tutorial.
Table 7-2 contains the description of the most common regular expression metacharacters.
You can use this table as a reference for understanding the rewrite rules.
Table 7-2. Metacharacters Commonly Used in Regular Expressions
Metacharacter Description
^ Matches the beginning of the line. In our case, it will always match the beginning
of the URL.
Pages:
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303