curl
cURL 是一个开源项目，其主要的产品是命令行工具 curl，以及 C 语言 API 库 libcurl。这两者的功能是基于网络协议，对指定的 URL 进行网络传输。
cURL 设计任何网络协议传输，不涉及对具体数据的具体处理。
cURL 的官方网站为：https://curl.haxx.se/
查看帮助
通过 --help 或者 -h 选项可以查看 curl 命令的帮助信息，具体为:
[jamza@jamza-vm etc]$ curl -h
Usage: curl [options...] <url>
Options: (H) means HTTP/HTTPS only, (F) means FTP only
--anyauth Pick "any" authentication method (H)
-a, --append Append to target file when uploading (F/SFTP)
--basic Use HTTP Basic Authentication (H)
--cacert FILE CA certificate to verify peer against (SSL)
--capath DIR CA directory to verify peer against (SSL)
-E, --cert CERT[:PASSWD] Client certificate file and password (SSL)
--cert-type TYPE Certificate file type (DER/PEM/ENG) (SSL)
--ciphers LIST SSL ciphers to use (SSL)
--compressed Request compressed response (using deflate or gzip)
-K, --config FILE Specify which config file to read
--connect-timeout SECONDS Maximum time allowed for connection
-C, --continue-at OFFSET Resumed transfer offset
-b, --cookie STRING/FILE String or file to read cookies from (H)
-c, --cookie-jar FILE Write cookies to this file after operation (H)
--create-dirs Create necessary local directory hierarchy
--crlf Convert LF to CRLF in upload
--crlfile FILE Get a CRL list in PEM format from the given file
-d, --data DATA HTTP POST data (H)
--data-ascii DATA HTTP POST ASCII data (H)
--data-binary DATA HTTP POST binary data (H)
--data-urlencode DATA HTTP POST data url encoded (H)
--delegation STRING GSS-API delegation permission
--digest Use HTTP Digest Authentication (H)
--disable-eprt Inhibit using EPRT or LPRT (F)
--disable-epsv Inhibit using EPSV (F)
-D, --dump-header FILE Write the headers to this file
--egd-file FILE EGD socket path for random data (SSL)
--engine ENGINGE Crypto engine (SSL). "--engine list" for list
-f, --fail Fail silently (no output at all) on HTTP errors (H)
-F, --form CONTENT Specify HTTP multipart POST data (H)
--form-string STRING Specify HTTP multipart POST data (H)
--ftp-account DATA Account data string (F)
--ftp-alternative-to-user COMMAND String to replace "USER [name]" (F)
--ftp-create-dirs Create the remote dirs if not present (F)
--ftp-method [MULTICWD/NOCWD/SINGLECWD] Control CWD usage (F)
--ftp-pasv Use PASV/EPSV instead of PORT (F)
-P, --ftp-port ADR Use PORT with given address instead of PASV (F)
--ftp-skip-pasv-ip Skip the IP address for PASV (F)
--ftp-pret Send PRET before PASV (for drftpd) (F)
--ftp-ssl-ccc Send CCC after authenticating (F)
--ftp-ssl-ccc-mode ACTIVE/PASSIVE Set CCC mode (F)
--ftp-ssl-control Require SSL/TLS for ftp login, clear for transfer (F)
-G, --get Send the -d data with a HTTP GET (H)
-g, --globoff Disable URL sequences and ranges using {} and []
-H, --header LINE Custom header to pass to server (H)
-I, --head Show document info only
-h, --help This help text
--hostpubmd5 MD5 Hex encoded MD5 string of the host public key. (SSH)
-0, --http1.0 Use HTTP 1.0 (H)
--ignore-content-length Ignore the HTTP Content-Length header
-i, --include Include protocol headers in the output (H/F)
-k, --insecure Allow connections to SSL sites without certs (H)
--interface INTERFACE Specify network interface/address to use
-4, --ipv4 Resolve name to IPv4 address
-6, --ipv6 Resolve name to IPv6 address
-j, --junk-session-cookies Ignore session cookies read from file (H)
--keepalive-time SECONDS Interval between keepalive probes
--key KEY Private key file name (SSL/SSH)
--key-type TYPE Private key file type (DER/PEM/ENG) (SSL)
--krb LEVEL Enable Kerberos with specified security level (F)
--libcurl FILE Dump libcurl equivalent code of this command line
--limit-rate RATE Limit transfer speed to this rate
-l, --list-only List only names of an FTP directory (F)
--local-port RANGE Force use of these local port numbers
-L, --location Follow redirects (H)
--location-trusted like --location and send auth to other hosts (H)
-M, --manual Display the full manual
--mail-from FROM Mail from this address
--mail-rcpt TO Mail to this receiver(s)
--mail-auth AUTH Originator address of the original email
--max-filesize BYTES Maximum file size to download (H/F)
--max-redirs NUM Maximum number of redirects allowed (H)
-m, --max-time SECONDS Maximum time allowed for the transfer
--metalink Process given URLs as metalink XML file
--negotiate Use HTTP Negotiate Authentication (H)
-n, --netrc Must read .netrc for user name and password
--netrc-optional Use either .netrc or URL; overrides -n
--netrc-file FILE Set up the netrc filename to use
-N, --no-buffer Disable buffering of the output stream
--no-keepalive Disable keepalive use on the connection
--no-sessionid Disable SSL session-ID reusing (SSL)
--noproxy List of hosts which do not use proxy
--ntlm Use HTTP NTLM authentication (H)
-o, --output FILE Write output to <file> instead of stdout
--pass PASS Pass phrase for the private key (SSL/SSH)
--post301 Do not switch to GET after following a 301 redirect (H)
--post302 Do not switch to GET after following a 302 redirect (H)
--post303 Do not switch to GET after following a 303 redirect (H)
-#, --progress-bar Display transfer progress as a progress bar
--proto PROTOCOLS Enable/disable specified protocols
--proto-redir PROTOCOLS Enable/disable specified protocols on redirect
-x, --proxy [PROTOCOL://]HOST[:PORT] Use proxy on given port
--proxy-anyauth Pick "any" proxy authentication method (H)
--proxy-basic Use Basic authentication on the proxy (H)
--proxy-digest Use Digest authentication on the proxy (H)
--proxy-negotiate Use Negotiate authentication on the proxy (H)
--proxy-ntlm Use NTLM authentication on the proxy (H)
-U, --proxy-user USER[:PASSWORD] Proxy user and password
--proxy1.0 HOST[:PORT] Use HTTP/1.0 proxy on given port
-p, --proxytunnel Operate through a HTTP proxy tunnel (using CONNECT)
--pubkey KEY Public key file name (SSH)
-Q, --quote CMD Send command(s) to server before transfer (F/SFTP)
--random-file FILE File for reading random data from (SSL)
-r, --range RANGE Retrieve only the bytes within a range
--raw Do HTTP "raw", without any transfer decoding (H)
-e, --referer Referer URL (H)
-J, --remote-header-name Use the header-provided filename (H)
-O, --remote-name Write output to a file named as the remote file
--remote-name-all Use the remote file name for all URLs
-R, --remote-time Set the remote file's time on the local output
-X, --request COMMAND Specify request command to use
--resolve HOST:PORT:ADDRESS Force resolve of HOST:PORT to ADDRESS
--retry NUM Retry request NUM times if transient problems occur
--retry-delay SECONDS When retrying, wait this many seconds between each
--retry-max-time SECONDS Retry only within this period
-S, --show-error Show error. With -s, make curl show errors when they occur
-s, --silent Silent mode. Don't output anything
--socks4 HOST[:PORT] SOCKS4 proxy on given host + port
--socks4a HOST[:PORT] SOCKS4a proxy on given host + port
--socks5 HOST[:PORT] SOCKS5 proxy on given host + port
--socks5-basic Enable username/password auth for SOCKS5 proxies
--socks5-gssapi Enable GSS-API auth for SOCKS5 proxies
--socks5-hostname HOST[:PORT] SOCKS5 proxy, pass host name to proxy
--socks5-gssapi-service NAME SOCKS5 proxy service name for gssapi
--socks5-gssapi-nec Compatibility with NEC SOCKS5 server
-Y, --speed-limit RATE Stop transfers below speed-limit for 'speed-time' secs
-y, --speed-time SECONDS Time for trig speed-limit abort. Defaults to 30
--ssl Try SSL/TLS (FTP, IMAP, POP3, SMTP)
--ssl-reqd Require SSL/TLS (FTP, IMAP, POP3, SMTP)
-2, --sslv2 Use SSLv2 (SSL)
-3, --sslv3 Use SSLv3 (SSL)
--ssl-allow-beast Allow security flaw to improve interop (SSL)
--stderr FILE Where to redirect stderr. - means stdout
--tcp-nodelay Use the TCP_NODELAY option
-t, --telnet-option OPT=VAL Set telnet option
--tftp-blksize VALUE Set TFTP BLKSIZE option (must be >512)
-z, --time-cond TIME Transfer based on a time condition
-1, --tlsv1 Use => TLSv1 (SSL)
--tlsv1.0 Use TLSv1.0 (SSL)
--tlsv1.1 Use TLSv1.1 (SSL)
--tlsv1.2 Use TLSv1.2 (SSL)
--tlsv1.3 Use TLSv1.3 (SSL)
--tls-max VERSION Use TLS up to VERSION (SSL)
--trace FILE Write a debug trace to the given file
--trace-ascii FILE Like --trace but without the hex output
--trace-time Add time stamps to trace/verbose output
--tr-encoding Request compressed transfer encoding (H)
-T, --upload-file FILE Transfer FILE to destination
--url URL URL to work with
-B, --use-ascii Use ASCII/text transfer
-u, --user USER[:PASSWORD] Server user and password
--tlsuser USER TLS username
--tlspassword STRING TLS password
--tlsauthtype STRING TLS authentication type (default SRP)
--unix-socket FILE Connect through this UNIX domain socket
-A, --user-agent STRING User-Agent to send to server (H)
-v, --verbose Make the operation more talkative
-V, --version Show version number and quit
-w, --write-out FORMAT What to output after completion
--xattr Store metadata in extended file attributes
-q If used as the first parameter disables .curlrc
可以看出，curl 命令支持的选项非常的多。 需要关注常用的选项即可。一般常用的选项包括：
-X, --request COMMAND Specify request command to use-i, --include Include protocol headers in the output (H/F)-I, --head Show document info only-o, --output FILE Write output to <file> instead of stdout-L, --location Follow redirects (H)
查看网页源码
直接在 curl 命令后面加上网址，即可获取网页源码。
[jamza@jamza-vm etc]$ curl http://www.zte.com.cn/
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html>
<head><title>307 Temporary Redirect</title></head>
<body bgcolor="white">
<h1>307 Temporary Redirect</h1>
<p>The requested resource resides temporarily under a different URI.</p>
<hr/>Powered by ZTE</body>
</html>
若需要将网页源码内容缓存下来，可以使用 -o 选项，具体为：
curl -o filename http://www.zte.com.cn/
显示头部信息
参数 -i 可以显示 http response 的头部信息，显示还包括网页代码内容。
[jamza@jamza-vm test]$ curl -i http://www.zte.com.cn/
HTTP/1.1 307 Temporary Redirect
Server: ZTE
Date: Fri, 19 Jun 2020 02:20:28 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 280
Connection: keep-alive
Location: https://www.zte.com.cn/
X-Content-Type-Options: nosniff
X-Xss-Protection: 1; mode=block
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html>
<head><title>307 Temporary Redirect</title></head>
<body bgcolor="white">
<h1>307 Temporary Redirect</h1>
<p>The requested resource resides temporarily under a different URI.</p>
<hr/>Powered by ZTE</body>
</html>
而参数 -I 只显示 http response 的头部信息，不显示网页代码内容。
[jamza@jamza-vm test]$ curl -I http://www.zte.com.cn/
HTTP/1.1 307 Temporary Redirect
Server: ZTE
Date: Fri, 19 Jun 2020 02:21:42 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 280
Connection: keep-alive
Location: https://www.zte.com.cn/
X-Content-Type-Options: nosniff
X-Xss-Protection: 1; mode=block
显示通信过程
参数 -v 可以显示一次 http 通信的整个过程，包括端口连接与头部信息。
[jamza@jamza-vm test]$ curl -v http://www.zte.com.cn/
* About to connect() to www.zte.com.cn port 80 (#0)
* Trying 10.30.6.85...
* Connected to www.zte.com.cn (10.30.6.85) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.29.0
> Host: www.zte.com.cn
> Accept: */*
>
< HTTP/1.1 307 Temporary Redirect
< Server: ZTE
< Date: Fri, 19 Jun 2020 02:23:48 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 280
< Connection: keep-alive
< Location: https://www.zte.com.cn/
< X-Content-Type-Options: nosniff
< X-Xss-Protection: 1; mode=block
<
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html>
<head><title>307 Temporary Redirect</title></head>
<body bgcolor="white">
<h1>307 Temporary Redirect</h1>
<p>The requested resource resides temporarily under a different URI.</p>
<hr/>Powered by ZTE</body>
</html>
* Connection #0 to host www.zte.com.cn left intact
HTTP 动词
curl 的默认 HTTP 动词为 GET，使用参数 -X 可以支持其他的动词类型。
curl -X POST www.example.com
curl -X DELETE www.example.com
增加头部信息
有时需要在 http request 之中，自行增加一个头信息。--header 参数就可以起到这个作用。
curl --header "Content-Type:application/json" http://example.com
HTTP 认证
有些网域需要 HTTP 认证，这时 curl 需要用到 --user 参数。
curl --user name:password example.com
