curl工具
工具的主页：https://curl.haxx.se/
NAME
curl - transfer a URL
SYNOPSIS
curl [options] [URL...]
DESCRIPTION
curl is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP). The command is designed to work without user interaction.
curl offers a busload of useful tricks like proxy support, user authentication, FTP upload, HTTP post, SSL connections, cookies, file transfer resume, Metalink, and more. As you will see below, the number of features will make your head spin!
curl is powered by libcurl for all transfer-related features. See libcurl(3) for details.
Usage:
1. 访问指定的URL
原文：https://www.cnblogs.com/sea-stream/p/10392504.html