curl命令行--强大的工具。通过各种参数，支持各种方式。
写几个常用的命令：
请求到的网站html
curl http://www.baidu.com
比如想在命令行上请求一个接口，post过去几个参数
curl -d "a=12&b=cc&d=1" "http://xx/yy/sign"
在请求中带上请求头header,多个header参数可以写多个H参数
curl -H 'OPCODE: 123456' http://127.0.0.1/index.php
比如想看下站点是否访问正常 返回200
curl -o /dev/null -s -w %{http_code} http://www.baidu.com
获取响应头信息
curl -D header.log http://www.baidu.com
下载资源
curl -O https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-3.2.11.tgz
例子：
curl -H 'bizline:yes' -H 'realip:108.92.185.42' -H 'opcode:123456' -H 'version:v1.0' -d 'data={"product":{"productid":"abc"},"uid":"123","filter":111111}' 'http://xxx.baidu.com/a/b'
其他参数获取帮助： 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-status Verify the status of the server certificate (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 Read config from FILE
--connect-timeout SECONDS Maximum time allowed for connection
-C, --continue-at OFFSET Resumed transfer OFFSET
-b, --cookie STRING/FILE Read cookies from STRING/FILE (H)
-c, --cookie-jar FILE Write cookies to 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-raw DATA HTTP POST data, '@' allowed (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)
--dns-servers DNS server addrs to use: 1.1.1.1;2.2.2.2
--dns-interface Interface to use for DNS requests
--dns-ipv4-addr IPv4 address to use for DNS requests, dot notation
--dns-ipv6-addr IPv6 address to use for DNS requests, dot notation
-D, --dump-header FILE Write the headers to FILE
--egd-file FILE EGD socket path for random data (SSL)
--engine ENGINE Crypto engine (use "--engine list" for list) (SSL)
-f, --fail Fail silently (no output at all) on HTTP errors (H)
--false-start Enable TLS False Start.
-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 Pass custom header LINE 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)
--http1.1 Use HTTP 1.1 (H)
--http2 Use HTTP 2 (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 Use network INTERFACE (or address)
-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 Wait SECONDS 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 security LEVEL (F)
--libcurl FILE Dump libcurl equivalent code of this command line
--limit-rate RATE Limit transfer speed to RATE
-l, --list-only List only mode (F/POP3)
--local-port RANGE Force use of RANGE for local port numbers
-L, --location Follow redirects (H)
--location-trusted Like '--location', and send auth to other hosts (H)
--login-options OPTIONS Server login options (IMAP, POP3, SMTP)
-M, --manual Display the full manual
--mail-from FROM Mail from this address (SMTP)
--mail-rcpt TO Mail to this/these addresses (SMTP)
--mail-auth AUTH Originator address of the original email (SMTP)
--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 (SPNEGO) authentication (H)
-n, --netrc Must read .netrc for user name and password
--netrc-optional Use either .netrc or URL; overrides -n
--netrc-file FILE Specify FILE for netrc
-:, --next Allows the following URL to use a separate set of options
--no-alpn Disable the ALPN TLS extension (H)
-N, --no-buffer Disable buffering of the output stream
--no-keepalive Disable keepalive use on the connection
--no-npn Disable the NPN TLS extension (H)
--no-sessionid Disable SSL session-ID reusing (SSL)
--noproxy List of hosts which do not use proxy
--ntlm Use HTTP NTLM authentication (H)
--oauth2-bearer TOKEN OAuth 2 Bearer Token (IMAP, POP3, SMTP)
-o, --output FILE Write to FILE instead of stdout
--pass PASS Pass phrase for the private key (SSL/SSH)
--path-as-is Do not squash .. sequences in URL path
--pinnedpubkey FILE Public key (PEM/DER) to verify peer against (OpenSSL/GnuTLS/NSS/wolfSSL/CyaSSL/GSKit only)
--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 PROTOCOLS
--proto-redir PROTOCOLS Enable/disable 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 HTTP Negotiate (SPNEGO) authentication on the proxy (H)
--proxy-ntlm Use NTLM authentication on the proxy (H)
--proxy-service-name NAME SPNEGO proxy service name
--service-name NAME SPNEGO service name
-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 RANGE
--raw Do HTTP "raw"; no 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 Wait SECONDS between retries
--retry-max-time SECONDS Retry only within this period
--sasl-ir Enable initial response in SASL authentication
-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-hostname HOST[:PORT] SOCKS5 proxy, pass host name to proxy
--socks5-gssapi-service NAME SOCKS5 proxy service name for GSS-API
--socks5-gssapi-nec Compatibility with NEC SOCKS5 server
-Y, --speed-limit RATE Stop transfers below RATE for 'speed-time' secs
-y, --speed-time SECONDS Trigger 'speed-limit' abort after SECONDS (default: 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 (use "-" for 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)
--trace FILE Write a debug trace to FILE
--trace-ascii FILE Like --trace, but without 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 Send User-Agent STRING to server (H)
-v, --verbose Make the operation more talkative
-V, --version Show version number and quit
-w, --write-out FORMAT Use output FORMAT after completion
--xattr Store metadata in extended file attributes
-q Disable .curlrc (must be first parameter)