将 Icon 命名为 favicon.ico 并放在 WebServer 的根目录下是因为当用户端使用的是 IE 浏览器，并且用户将你的网站保存到收藏夹中时，IE 浏览器会自动搜索 Web Server 的根目录，查找是否有 favicon.ico 文件，如果有，就作为收藏夹该页面的 Icon 。

首先，下载并解压缩到您的 WordPress 插件，然后在您的 WordPress 中激活该插件就可以了。
在适当的位置中加入以下代码既可.一般是加入到模板Sidebar 这个文件里.

[UNKNOWN NODETYPE 7]?>?>?>?>?>

updated: 不断修正一些小问题

Source: Comprehensive guide to .htaccess

Officical reference: Directive Quick Reference

1 Introduction 介绍
文件名 .htaccess 属性 644 (RW-R–R–)
htaccess会影响它所在目录下的所有子目录
注意大多数内容都要求保持在一行之内，不要换行，否则会引起错误

2 Error Documents 错误文档
Official document: ErrorDocument Directive

ErrorDocument code document
例子
ErrorDocument 400 /errors/badrequest.html
ErrorDocument 404 http://yoursite/errors/notfound.html
ErrorDocument 401 “

Authorization Required

”
(注意之后内容如果出现的双引号需要转义为 \”)

常见HTTP状态码

Successful Client Requests

200 OK
201 Created
202 Accepted
203 Non-Authorative Information
204 No Content
205 Reset Content
206 Partial Content

Client Request Redirected

300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
303 See Other
304 Not Modified
305 Use Proxy

Client Request Errors

400 Bad Request
401 Authorization Required
402 Payment Required (not used yet)
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable (encoding)
407 Proxy Authentication Required
408 Request Timed Out
409 Conflicting Request
410 Gone
411 Content Length Required
412 Precondition Failed
413 Request Entity Too Long
414 Request URI Too Long
415 Unsupported Media Type

Server Errors

500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported

3 Password Protection 密码保护
Official document: Authentication, Authorization and Access Control

假设密码文件为.htpasswd

AuthUserFile /usr/local/safedir/.htpasswd (这里必须使用全路径名)
AuthName EnterPassword
AuthType Basic

两种常见验证方式:
Require user windix
(仅允许用户windix登陆)
Require valid-user
(所有合法用户都可登陆)

Tip: 如何生成密码文件
使用htpasswd命令(apache自带)

第一次生成需要创建密码文件
htpasswd -c .htpasswd user1

之后增加新用户
htpasswd .htpasswd user2

4 Enabling SSI Via htaccess 通过htaccess允许SSI(Server Side Including)功能
AddType text/html .shtml
AddHandler server-parsed .shtml
Options Indexes FollowSymLinks Includes

DirectoryIndex index.shtml index.html

5 Blocking users by IP 根据IP阻止用户访问
order allow,deny
deny from 123.45.6.7
deny from 12.34.5. (整个C类地址)
allow from all

6 Blocking users/sites by referrer 根据referrer阻止用户/站点访问
需要mod_rewrite模块

例1. 阻止单一referrer: badsite.com
RewriteEngine on
# Options +FollowSymlinks
RewriteCond %{HTTP_REFERER} badsite\.com [NC]
RewriteRule .* – [F]

例2. 阻止多个referrer: badsite1.com, badsite2.com
RewriteEngine on
# Options +FollowSymlinks
RewriteCond %{HTTP_REFERER} badsite1\.com [NC,OR]
RewriteCond %{HTTP_REFERER} badsite2\.com
RewriteRule .* – [F]

[NC] – 大小写不敏感(Case-insensite)
[F] – 403 Forbidden

注意以上代码注释掉了”Options +FollowSymlinks”这个语句。如果服务器未在 httpd.conf 的 段落设置 FollowSymLinks, 则需要加上这句，否则会得到”500 Internal Server error”错误。

7 Blocking bad bots and site rippers (aka offline browsers) 阻止坏爬虫和离线浏览器
需要mod_rewrite模块

坏爬虫? 比如一些抓垃圾email地址的爬虫和不遵守robots.txt的爬虫(如baidu?)
可以根据 HTTP_USER_AGENT 来判断它们
(但是还有更无耻的如”中搜 zhongsou.com”之流把自己的agent设置为 “Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)” 太流氓了，就无能为力了)

RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} ^BlackWidow [OR]
RewriteCond %{HTTP_USER_AGENT} ^Bot\ mailto:craftbot@yahoo.com [OR]
RewriteCond %{HTTP_USER_AGENT} ^ChinaClaw [OR]
RewriteCond %{HTTP_USER_AGENT} ^Custo [OR]
RewriteCond %{HTTP_USER_AGENT} ^DISCo [OR]
RewriteCond %{HTTP_USER_AGENT} ^Download\ Demon [OR]
RewriteCond %{HTTP_USER_AGENT} ^eCatch [OR]
RewriteCond %{HTTP_USER_AGENT} ^EirGrabber [OR]
RewriteCond %{HTTP_USER_AGENT} ^EmailSiphon [OR]
RewriteCond %{HTTP_USER_AGENT} ^EmailWolf [OR]
RewriteCond %{HTTP_USER_AGENT} ^Express\ WebPictures [OR]
RewriteCond %{HTTP_USER_AGENT} ^ExtractorPro [OR]
RewriteCond %{HTTP_USER_AGENT} ^EyeNetIE [OR]
RewriteCond %{HTTP_USER_AGENT} ^FlashGet [OR]
RewriteCond %{HTTP_USER_AGENT} ^GetRight [OR]
RewriteCond %{HTTP_USER_AGENT} ^GetWeb! [OR]
RewriteCond %{HTTP_USER_AGENT} ^Go!Zilla [OR]
RewriteCond %{HTTP_USER_AGENT} ^Go-Ahead-Got-It [OR]
RewriteCond %{HTTP_USER_AGENT} ^GrabNet [OR]
RewriteCond %{HTTP_USER_AGENT} ^Grafula [OR]
RewriteCond %{HTTP_USER_AGENT} ^HMView [OR]
RewriteCond %{HTTP_USER_AGENT} HTTrack [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^Image\ Stripper [OR]
RewriteCond %{HTTP_USER_AGENT} ^Image\ Sucker [OR]
RewriteCond %{HTTP_USER_AGENT} Indy\ Library [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^InterGET [OR]
RewriteCond %{HTTP_USER_AGENT} ^Internet\ Ninja [OR]
RewriteCond %{HTTP_USER_AGENT} ^JetCar [OR]
RewriteCond %{HTTP_USER_AGENT} ^JOC\ Web\ Spider [OR]
RewriteCond %{HTTP_USER_AGENT} ^larbin [OR]
RewriteCond %{HTTP_USER_AGENT} ^LeechFTP [OR]
RewriteCond %{HTTP_USER_AGENT} ^Mass\ Downloader [OR]
RewriteCond %{HTTP_USER_AGENT} ^MIDown\ tool [OR]
RewriteCond %{HTTP_USER_AGENT} ^Mister\ PiX [OR]
RewriteCond %{HTTP_USER_AGENT} ^Navroad [OR]
RewriteCond %{HTTP_USER_AGENT} ^NearSite [OR]
RewriteCond %{HTTP_USER_AGENT} ^NetAnts [OR]
RewriteCond %{HTTP_USER_AGENT} ^NetSpider [OR]
RewriteCond %{HTTP_USER_AGENT} ^Net\ Vampire [OR]
RewriteCond %{HTTP_USER_AGENT} ^NetZIP [OR]
RewriteCond %{HTTP_USER_AGENT} ^Octopus [OR]
RewriteCond %{HTTP_USER_AGENT} ^Offline\ Explorer [OR]
RewriteCond %{HTTP_USER_AGENT} ^Offline\ Navigator [OR]
RewriteCond %{HTTP_USER_AGENT} ^PageGrabber [OR]
RewriteCond %{HTTP_USER_AGENT} ^Papa\ Foto [OR]
RewriteCond %{HTTP_USER_AGENT} ^pavuk [OR]
RewriteCond %{HTTP_USER_AGENT} ^pcBrowser [OR]
RewriteCond %{HTTP_USER_AGENT} ^RealDownload [OR]
RewriteCond %{HTTP_USER_AGENT} ^ReGet [OR]
RewriteCond %{HTTP_USER_AGENT} ^SiteSnagger [OR]
RewriteCond %{HTTP_USER_AGENT} ^SmartDownload [OR]
RewriteCond %{HTTP_USER_AGENT} ^SuperBot [OR]
RewriteCond %{HTTP_USER_AGENT} ^SuperHTTP [OR]
RewriteCond %{HTTP_USER_AGENT} ^Surfbot [OR]
RewriteCond %{HTTP_USER_AGENT} ^tAkeOut [OR]
RewriteCond %{HTTP_USER_AGENT} ^Teleport\ Pro [OR]
RewriteCond %{HTTP_USER_AGENT} ^VoidEYE [OR]
RewriteCond %{HTTP_USER_AGENT} ^Web\ Image\ Collector [OR]
RewriteCond %{HTTP_USER_AGENT} ^Web\ Sucker [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebAuto [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebCopier [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebFetch [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebGo\ IS [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebLeacher [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebReaper [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebSauger [OR]
RewriteCond %{HTTP_USER_AGENT} ^Website\ eXtractor [OR]
RewriteCond %{HTTP_USER_AGENT} ^Website\ Quester [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebStripper [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebWhacker [OR]
RewriteCond %{HTTP_USER_AGENT} ^WebZIP [OR]
RewriteCond %{HTTP_USER_AGENT} ^Wget [OR]
RewriteCond %{HTTP_USER_AGENT} ^Widow [OR]
RewriteCond %{HTTP_USER_AGENT} ^WWWOFFLE [OR]
RewriteCond %{HTTP_USER_AGENT} ^Xaldon\ WebSpider [OR]
RewriteCond %{HTTP_USER_AGENT} ^Zeus
RewriteRule ^.* – [F,L]

[F] – 403 Forbidden
[L] – ?

8 Change your default directory page 改变缺省目录页面
DirectoryIndex index.html index.php index.cgi index.pl

9 Redirects 转向
单个文件
Redirect /old_dir/old_file.html http://yoursite.com/new_dir/new_file.html

整个目录
Redirect /old_dir http://yoursite.com/new_dir

效果: 如同将目录移动位置一样
http://yoursite.com/old_dir -> http://yoursite.com/new_dir
http://yoursite.com/old_dir/dir1/test.html -> http://yoursite.com/new_dir/dir1/test.html

Tip: 使用用户目录时Redirect不能转向的解决方法

当你使用Apache默认的用户目录，如 http://mysite.com/~windix，当你想转向 http://mysite.com/~windix/jump时，你会发现下面这个Redirect不工作:
Redirect /jump http://www.google.com

正确的方法是改成
Redirect /~windix/jump http://www.google.com

(source: .htaccess Redirect in “Sites” not redirecting: why?)

10 Prevent viewing of .htaccess file 防止.htaccess文件被查看

order allow,deny
deny from all

11 Adding MIME Types 添加 MIME 类型
AddType application/x-shockwave-flash swf

Tips: 设置类型为 application/octet-stream 将提示下载

12 Preventing hot linking of images and other file types 防盗链
需要mod_rewrite模块

RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www/\.)?mydomain.com/.*$ [NC]
RewriteRule \.(gif|jpg|js|css)$ – [F]

解析:
若 HTTP_REFERER 非空 (来源为其他站点，非直接连接) 并且
若 HTTP_REFERER 非(www.)mydomain.com开头(忽略大小写[NC]) (来源非本站)
对于所有含有 .gif/.jpg/.js/.css 结尾的文件给出 403 Forbidden 错误[F]

也可指定响应，如下例显示替换图片

RewriteRule \.(gif|jpg)$ http://www.mydomain.com/angry.gif [R,L]

[R] – 转向(Redirect)
[L] – 连接(Link)

13 Preventing Directory Listing 防止目录列表时显示
IndexIgnore *

IndexIgnore *.jpg *.gif

Tips:
允许目录列表显示: Options +Indexes
禁止牧师列表显示: Options -Indexes
显示提示信息: 页首 文件HEADER, 页尾 文件README

要在Apache里运行rewrite的话，必须先安装mod_rewrite的组件，就是一个mod_rewrite.c文件，然后必须在./configure的时候要放上mod_rewrite就能安装。
一般配置rewrite的话，可以在httpd.conf里面配置，也能在网页当前目录的.htaccess文件里进行定义来决定重定向去那个文件，那样的话，就非常具有灵活性了，同样也能够适合虚拟主机用户来做。

我们看一个.htaccess文件的例子：

1
2 RewriteEngine On
3 RewriteBase /
4 RewriteCond %{REQUEST_FILENAME} -f [OR]
5 RewriteCond %{REQUEST_FILENAME} -d
6 RewriteRule ^.*$ – [S=42]
7
8 #RewriteRule ^share/$ /share.php [QSA,L]
9 RewriteRule ^tag/([^/]+)/?$ /user_tags.php?tag=$1 [QSA,L]
10 RewriteRule ^city/([^/]+)/?$ /user_city.php?tag=$1 [QSA,L]
11 #RewriteRule ^([^/]+)/day/([^/]+)/?$ /user_share.php?id=$1&s=1&selTime=$2 [QSA,L]
12 #RewriteRule ^([^/]+)/day/([^/]+)/?$ /user_share.php?id=$1&s=1&selTime=$2 [QSA,L]
13
14 RewriteRule ^([^/]+)/day/([^/]+)/?$ /user_share.php?id=$1&s=1&selTime=$2 [QSA,L]
15 RewriteRule ^([^/]+)/week/([^/]+)/?$ /user_share.php?id=$1&s=2&selTime=$2 [QSA,L]
16 RewRiteRule ^([^/]+)/month/([^/]+)/?$ /user_share.php?id=$1&s=3&selTime=$2 [QSA,L]
17
18 RewriteRule ^([^/]+)/day/?$ /user_share.php?id=$1&s=1 [QSA,L]
19 RewriteRule ^([^/]+)/week/?$ /user_share.php?id=$1&s=2 [QSA,L]
20 RewriteRule ^([^/]+)/month/?$ /user_share.php?id=$1&s=3 [QSA,L]
21
22 RewriteRule ^([^/]+)/?$ /user_share.php?id=$1 [QSA,L]
23

比较长吧，我们就简单关注一下关键的内容。之间就是定义的内容，RewriteEngine就是确定是否运行URL重写功能，RewriteBase就是基本的路径是什么，最关键的就是下面的RewriteRule，就是我们需要重写的规则了，这里应用了兼容Perl规则的正则表达式：

Text:
. 匹配任意单个字符
[chars] 匹配当前字符
[^chars] 不匹配当前字符
text1|text2 包含text1或者text2任何一个

Quantifiers:
? 零个或者一个?号前的字符
* 零个或者任意个任意长度的任意字符
+ 一个或者任意个任意长度的字符

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 RHS of a RewriteRule with $N)

Anchors:
^ 匹配内容开始标记
$ 匹配内容结束标记

Escaping:
\char 使用\来进行特殊字符的转义，包括”.[]()”等字符的转义

基本规则如上，比如下面的正则表达式：^/([^/]+)/~([^/]+)/(.*)$ 就是能够匹配象 /Language/~ Realname/…/File 这样的路径。

那么从这个角度去看上面的内容就比较容易理解了。我们简单看一下RewriteRule指令的规则：
RewriteRule 访问的路径 需要指向的真实路径
这样就很清楚了，比如说我要把/user/heiyeluren重定向到/user.php?uid=heiyeluren那么我的规则就必须这样：
RewriteRule ^user/([^/]+)$ ^/user.php?uid=$2 [QSA,L]

举一反三，就很容易理解规则如何去写，也就能够理解上面规则脚本的内容了。

没有清楚的，请参考附上的链接，更深入的了解具体内容。写的不好请见谅。

Structure Tags

You can use these tags to customize your “Pretty” or “Almost Pretty” permalinks.

%year% 

The year of the post, four digits, for example 2004

%monthnum% 

Month of the year, for example 05

%day% 

Day of the month, for example 28

%hour% 

Hour of the day, for example 15

%minute% 

Minute of the hour, for example 43

%second% 

Second of the minute, for example 33

%postname% 

A sanitized version of the title of the post. So “This Is A Great Post!” becomes “this-is-a-great-post” in the URI (see note below)

%post_id% 

The unique ID # of the post, for example 423

%category% 

A sanitized version of the category name. Nested sub-categories appear as nested directories in the URI.

%author% 

A sanitized version of the author name.

These types of permalinks work on most systems without any problems, but there are still some conditions where problems occur.

Note on using only %postname% 

If you use postname as the only element in your permalinks to create a structure such as myblog.com/post-title, the rewrite rules may make it impossible to access pages such as your stylesheet (which has a similar format) or the wp-admin folder. It’s best to include some numeric data (e.g. the post ID or date) in the permalink to prevent this from happening. Additionally, WordPress v1.2.x requires the use of a date structure in order for some features, such as the calendar, to function properly. /%year%/%monthnum%/%day%/%postname%/ is always a good start.

Note on using %category% 

%category% does not work correctly with some implementations of mod_rewrite in Apache versions prior to 2. If you are using Apache 1 and experience problems with using %category, either do not use %category% in your permalink structure, or refer to Schlueterica’s plugin (http://isaacschlueter.com/plugins/i-made/lucky-13-rewrite/).

Note on using %category% with multiple categories on a post 

Where you assign multiple categories to a post, only 1 can show up in the permalink. This will be the lowest numbered category (see Manage Categories). The post will still be accessible through all the categories as normal.

Properly terminating permalinks 

It’s important to guarantee permalinks lead to individual posts within your custom URI, so make sure to end a virtual site structure with either %post_id% or %postname%

/%year%/%monthnum%/%day%/%postname%/