curl ： 命令行里访问网页，网站，下载文件
[root@lxglinux ~]# curl www.apelearn.com #这个命令之后，出现了www.apelearn.com网站的源码一大堆
[root@lxglinux ~]# curl -I !$ -I省略源码
curl -I www.apelearn.com
HTTP/1.1 200 OK
Server: nginx
Date: Wed, 27 Jan 2016 15:16:31 GMT
Content-Type: text/html
Connection: keep-alive
Vary: Accept-Encoding
X-Powered-By: PHP/5.3.27
上面注意到有一个200 OK ，其实常见的状态码还有200 301 302 404 403 502 503
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[root@lxglinux ~]# curl -I www.lishiming.net curl一下这个网站发现一个状态码301，意味着设置了跳转
HTTP/1.1 301 Moved Permanently
Server: nginx/1.0.15
Date: Wed, 27 Jan 2016 15:23:44 GMT
Content-Type: text/html
Content-Length: 185
Connection: keep-alive
Location: http://www.apelearn.com/bbs/forum.php #跳转到这个域名下。
[root@lxglinux ~]#
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[root@lxglinux ~]# vim /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.1.1 www.qq.com
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"/etc/hosts" 3L, 181C
[root@lxglinux ~]# ping www.qq.com
PING www.qq.com (192.168.1.1) 56(84) bytes of data.
---------------------------------------------------------------------------
[root@lxglinux ~]# ping www.qq.com
PING www.qq.com (220.181.138.29) 56(84) bytes of data.
64 bytes from 220.181.138.29: icmp_seq=1 ttl=128 time=78.3 ms
64 bytes from 220.181.138.29: icmp_seq=2 ttl=128 time=77.5 ms
64 bytes from 220.181.138.29: icmp_seq=3 ttl=128 time=83.9 ms
64 bytes from 220.181.138.29: icmp_seq=4 ttl=128 time=87.4 ms
64 bytes from 220.181.138.29: icmp_seq=5 ttl=128 time=77.2 ms
64 bytes from 220.181.138.29: icmp_seq=6 ttl=128 time=77.6 ms
^Z
[4]+ Stopped ping www.qq.com
[root@lxglinux ~]#
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glinux ~]# curl -x220.181.138.29:80 www.qq.com -I #通过-x命令即使配置文件修改了，也能ping到正确的地址，别忘了 加I省略信息
HTTP/1.1 200 OK
Server: squid/3.4.3
Date: Wed, 27 Jan 2016 15:32:12 GMT
Content-Type: text/html; charset=GB2312
Connection: keep-alive
Vary: Accept-Encoding
Vary: Accept-Encoding
Expires: Wed, 27 Jan 2016 15:33:12 GMT
Cache-Control: max-age=60
Vary: Accept-Encoding
Vary: Accept-Encoding
X-Cache: HIT from beijing.qq.com
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[root@lxglinux ~]# curl -IV www.qq.com #显示访问过程。
curl 7.19.7 (i386-redhat-linux-gnu) libcurl/7.19.7 NSS/3.14.0.0 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
Protocols: tftp ftp telnet dict ldap ldaps http file https ftps scp sftp
Features: GSS-Negotiate IDN IPv6 Largefile NTLM SSL libz
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[root@lxglinux ~]# curl -Iv www.qq.com
* About to connect() to www.qq.com port 80 (#0)
* Trying 220.181.138.29... connected
* Connected to www.qq.com (220.181.138.29) port 80 (#0)
> HEAD / HTTP/1.1
> User-Agent: curl/7.19.7 (i386-redhat-linux-gnu) libcurl/7.19.7 NSS/3.14.0.0 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
> Host: www.qq.com
> Accept: */*
>
< HTTP/1.1 200 OK
HTTP/1.1 200 OK
< Server: squid/3.4.3
Server: squid/3.4.3
< Date: Wed, 27 Jan 2016 15:45:45 GMT
Date: Wed, 27 Jan 2016 15:45:45 GMT
< Content-Type: text/html; charset=GB2312
Content-Type: text/html; charset=GB2312
< Connection: keep-alive
Connection: keep-alive
< Vary: Accept-Encoding
Vary: Accept-Encoding
< Vary: Accept-Encoding
Vary: Accept-Encoding
< Expires: Wed, 27 Jan 2016 15:46:45 GMT
Expires: Wed, 27 Jan 2016 15:46:45 GMT
< Cache-Control: max-age=60
Cache-Control: max-age=60
< Vary: Accept-Encoding
Vary: Accept-Encoding
< Vary: Accept-Encoding
Vary: Accept-Encoding
< X-Cache: HIT from beijing.qq.com
X-Cache: HIT from beijing.qq.com
* no chunk, no close, no size. Assume close to signal end
<
* Closing connection #0
*********useragent 标示，每个网站都有它自己的标识。
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[root@lxglinux ~]# curl -u username:password http://www.qq.com ^C 指定user访问网站
[root@lxglinux ~]# curl -u username:password http://www.qq.com -I 当然后面可以加-I，简略信息。
HTTP/1.1 200 OK
Server: squid/3.4.3
Date: Wed, 27 Jan 2016 15:52:13 GMT
Content-Type: text/html; charset=GB2312
Connection: keep-alive
Vary: Accept-Encoding
Vary: Accept-Encoding
Expires: Wed, 27 Jan 2016 15:53:13 GMT
Cache-Control: max-age=60
Vary: Accept-Encoding
Vary: Accept-Encoding
X-Cache: HIT from beijing.qq.com
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[root@lxglinux ~]# curl -O http://passport.ixpub.net/data/avatar/016/72/81/39_avatar_middle.jpg 最后一节是默认名称，跟网页中的保持一致 -大O不能指定名称，重新命名。
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 5725 100 5725 0 0 1060 0 0:00:05 0:00:05 --:--:-- 35559
[root@lxglinux ~]# ls 39_avatar_middle.jpg
39_avatar_middle.jpg
[root@lxglinux ~]# curl -o xiazai http://passport.ixpub.net/data/avatar/016/72/81/39_avatar_middle.jp #-小O的话可以指定重命名的名称。