nginx中rewrite和if的使用及配置方式

rewrite  <正则表达式>  <跳转后的内容>  [rewrite支持的flag标记]

^：匹配输入字符串的起始位置
$：匹配输入字符串的结束位置
*****：匹配前面的字符零次或多次
+：匹配前面的字符一次或多次
?：匹配前面的字符零次或一次
.：匹配除\n之外的任何单个字符 使用[.\n]可以匹配包括\n在内的任意字符
****：转义符
\d：匹配纯数字
{n}：重复n次
{n,}：重复n次或更多次
[c]：匹配单个字符c
[a-z]：匹配a-z小写字母的任意一个
[a-zA-Z]：匹配a-z小写字母或A-Z大写字母的任意一个

[root@nginx ~]# vim /usr/local/nginx/conf/nginx.conf		
		root /hhh/xxx;
    	location / {
                rewrite /1.html /2.html;
                rewrite /2.html /3.html;
        }

        location /2.html {
                rewrite /2.html /a.html;
        }

        location /3.html {
                rewrite /3.html /b.html;
        }
        
[root@nginx ~]# nginx -t
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful[root@nginx ~]# systemctl restart nginx

[root@nginx ~]# mkdir -p /hhh/xxx
[root@nginx ~]# echo "web1" > /hhh/xxx/1.html
[root@nginx ~]# echo "web2" > /hhh/xxx/2.html 
[root@nginx ~]# echo "web3" > /hhh/xxx/3.html
[root@nginx ~]# echo "web a" > /hhh/xxx/a.html
[root@nginx ~]# echo "web b" > /hhh/xxx/b.html
[root@nginx ~]# curl 192.168.183.138/1.html
web b

		location / {                                
                rewrite /1.html /2.html break;
                rewrite /2.html /3.html;            
        }                                                                                     
        location /2.html {                          
                rewrite /2.html /a.html;            
        }                                      
                                                
        location /3.html {                          
                rewrite /3.html /b.html;            
        }   
        
[root@nginx ~]# curl 192.168.183.138/1.html
web2

		location / {
                rewrite /1.html /2.html last;
                rewrite /2.html /3.html;
        }

        location /2.html {
                rewrite /2.html /a.html;
        }

        location /3.html {
                rewrite /3.html /b.html;
        }
        
[root@nginx ~]# curl 192.168.183.138/1.html     web a

if ($http_user_agent ~ Firefox) {
  rewrite ^(.*)$ /firefox/$1 break;
}

if ($http_user_agent ~ MSIE) {
  rewrite ^(.*)$ /msie/$1 break;
}

if ($http_user_agent ~ Chrome) {
  rewrite ^(.*)$ /chrome/$1 break;
}

location ~* \.(jpg|gif|jpeg|png)$ {
  valid_referers none blocked www.idfsoft.com;
  if ($invalid_referer) {
    rewrite ^/ http://www.idfsoft.com/403.html;
  }
}