下载：
https://curl.haxx.se/download.html
安装：
二进制安装。即解压即可。
使用
1、获取页面内容。
不加任何参数时，默认会发送GET请求来获取url内容到标准输出。
curl url
D:\AppCache\GolangHome\src\learn>curl www.apple.com#===============================================================
D:\AppCache\GolangHome\src\learn>curl www.google.com
curl: (52) Empty reply from server
#===============================================================
D:\AppCache\GolangHome\src\learn>curl www.xiaomi.com
301 Moved Permanently
Powered by MiWeb
#==============================================================
D:\AppCache\GolangHome\src\learn>curl www.baidu.com
c.com/r/www/cache/bdorz/baidu.min.css>
src=//www.baidu.com/img/bd_logo1.png width=270 height=129>
©2017 Baidu href=http://www.baidu.com/duty/>使用百度前必读 意见反馈 京ICP证030173号 
#===================================================================D:\AppCache\GolangHome\src\learn>
分别测试了苹果、谷歌、小米、百度。发现获得的页面内容大小相差较大。苹果啥也不给，霸道。谷歌则给了一句温馨提示语。小米则简洁地回应了一个html，重定向了。百度则回应一堆信息。
2、获取http响应的头部信息。
D:\AppCache\GolangHome\src\learn>curl -I http://www.apple.com
HTTP/1.1 301 Moved Permanently
Server: GHost
Content-Length: 0
Location: https://www.apple.com/
Cache-Control: max-age=0
Expires: Sun, 22 Sep 2019 04:59:29 GMT
Date: Sun, 22 Sep 2019 04:59:29 GMT
Connection: keep-alive
strict-transport-security: max-age=31536000
Set-Cookie: geo=CN; path=/; domain=.apple.com
Set-Cookie: ccl=shCgHjtuYBarTIycW/rvIg==; path=/; domain=.apple.com
#===================================================================
D:\AppCache\GolangHome\src\learn>curl -I http://www.google.com
curl: (52) Empty reply from server
#====================================================================
D:\AppCache\GolangHome\src\learn>curl -I http://www.xiaomi.com
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sun, 22 Sep 2019 04:59:53 GMT
Content-Type: text/html
Content-Length: 223
Connection: close
Location: https://www.mi.com
#===================================================================
D:\AppCache\GolangHome\src\learn>curl -I http://www.baidu.com
HTTP/1.1 200 OK
Server: bfe/1.0.8.18
Date: Sun, 22 Sep 2019 05:00:01 GMT
Content-Type: text/html
Content-Length: 277
Last-Modified: Mon, 13 Jun 2016 02:50:23 GMT
Connection: Keep-Alive
ETag: "575e1f6f-115"
Cache-Control: private, no-cache, no-store, proxy-revalidate, no-transform
Pragma: no-cache
Accept-Ranges: bytes
#==========================================================================
D:\AppCache\GolangHome\src\learn>
这次谷歌给的响应头依然是一句简短的提示语，太节约资源了。其他三个则普通给出响应头，其中苹果和小米都重定向了。
4、同时给出http的响应头和响应体。
D:\AppCache\GolangHome\src\learn>curl -i http://www.google.com
curl: (52) Empty reply from server
#===============================================================
D:\AppCache\GolangHome\src\learn>curl -i http://www.apple.com
HTTP/1.1 301 Moved Permanently
Server: GHost
Content-Length: 0
Location: https://www.apple.com/
Cache-Control: max-age=0
Expires: Sun, 22 Sep 2019 05:10:26 GMT
Date: Sun, 22 Sep 2019 05:10:26 GMT
Connection: keep-alive
strict-transport-security: max-age=31536000
Set-Cookie: geo=CN; path=/; domain=.apple.com
Set-Cookie: ccl=Pnj18CxjBB4h7LQaKIIkxg==; path=/; domain=.apple.com
#=====================================================================
D:\AppCache\GolangHome\src\learn>curl -i http://www.xiaomi.com
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sun, 22 Sep 2019 05:10:35 GMT
Content-Type: text/html
Content-Length: 223
Connection: close
Location: https://www.mi.com
301 Moved Permanently
Powered by MiWeb
#=============================================================
D:\AppCache\GolangHome\src\learn>curl -i http://www.baidu.com
HTTP/1.1 200 OK
Server: bfe/1.0.8.18
Date: Sun, 22 Sep 2019 05:10:47 GMT
Content-Type: text/html
Content-Length: 2381
Last-Modified: Mon, 23 Jan 2017 13:28:12 GMT
Connection: Keep-Alive
ETag: "588604ec-94d"
Cache-Control: private, no-cache, no-store, proxy-revalidate, no-transform
Pragma: no-cache
Set-Cookie: BDORZ=27315; max-age=86400; domain=.baidu.com; path=/
Accept-Ranges: bytes
c.com/r/www/cache/bdorz/baidu.min.css>
src=//www.baidu.com/img/bd_logo1.png width=270 height=129>
©2017 Baidu href=http://www.baidu.com/duty/>使用百度前必读 意见反馈 京ICP证030173号
#====================================================
D:\AppCache\GolangHome\src\learn>
谷歌依旧发挥着极简风格，就一句话。苹果给头不给体。小米则都给。百度则臃肿不堪。