一：curl簡介及語法

curl是一個訪問url的工具，可以用它構造http request報文，且可以解析服務器返回的http response，額外還支持cookie特性，可以用curl完成web瀏覽器的基本功能，curl還支持HTTPS/FTP/FTPS/TELNET/LDAP等協議。如下圖：

[root@VM_110_98_centos ~]# curl --help

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-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)

--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

常用選項：

-v 詳細輸出，包含請求和響應的首部

-o test 將指定curl返回保存為test文件，內容從html/jpg到各種MIME類型文件

-O 把輸出寫到該文件中，保留遠程文件的文件名

-C 在保存文件時進行續傳

-x ip:port 指定使用的http代理

-c <file> 保存服務器的cookie文件

-H <header:value> 為HTTP請求設置任意header及值

-S 顯示錯誤信息

-s 靜默模式，不輸出任何信息

-G 以get的方式發送數據

-f 連接失敗是不顯示http錯誤

-d 以post方式傳送數據

二：實例

1.只返回狀態碼

curl -I -m 15 -o /dev/null -s -w %{http_code} www.baidu.com

-I 僅測試HTTP頭信息

-m 15 最多查詢15s

-o /dev/null 屏蔽原有輸出信息

-s 靜默模式，不輸出任何東西

-w %{http_code} 控制額外輸出

2.自定義顯示文字和返回狀態碼

curl -I -m 15 -o /dev/null -s -w "我愛你：%{http_code}" www.baidu.com

3.抓取頁面內容到一個文件中（test文件不需要創建）

4. 後面的url要具體到某個文件，不然抓不下來，我們還可以用正則來抓取東西。

下圖是在百度中搜索這幾天比較熱門的李小璐事件為例

復制黏貼這個網址紅色箭頭的網址http://www.lutouwang.net/detail/17/1231/8jbutue9c.html

curl -O http://www.lutouwang.net/detail/17/1231/8jbutue9c.html

5. 通過--limit-rate選項對CURL的最大網絡使用進行限制

curl --limit-rate 1000B -O http://www.lutouwang.net/detail/17/1231/8jbutue9c.html

6. 在訪問需要授權的頁面時，可通過-u選項提供用戶名和密碼進行授權

通常的做法是在命令行只輸入用戶名，之後會提示輸入密碼，這樣可以保證在查看歷史命令記錄時不會將密碼泄露，本例以訪問svn服務器為例。

curl -u 用戶名 svn地址，之後輸入密碼即可看到目錄

附：官方文檔https://curl.haxx.se/docs/manpage.html

curl 命令詳解