* 更新日志

* 20240809 补充2.6 和 2.7

0 前言

在网络时代，有经常需要在网络上传输数据，时我们需要通过网络下载文件，为了满足这种时代需要，Linux提供了众多网络命令，我们今天先研究curl命令。例如，我们可以使用 <code>curl 从 URL 下载文件，或将文件上传到服务器。

1 curl命令 的功能、格式和选项说明

我们可以使用 curl --man | more 命令查看curl命令 的帮助信息。

[purpleEndurer @ bash ~]curl --man | more

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NAME

curl - transfer a URL

SYNOPSIS

curl [options] [URL...]

DESCRIPTION

curl is a tool to transfer data from or to a server, using one o

f the

supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP,

IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMTP, SMTPS,

TELNET and TFTP). The command is designed to work without user inter-

action.

curl offers a busload of useful tricks like proxy support, user authen-

tication, FTP upload, HTTP post, SSL connections, cookies, file trans-

fer resume, Metalink, and more. As you will see below, the number of

--More--

1.1 curl命令 的功能

curl 是 client url 或 command line url 的缩写。

curl是一个从命令行通过互联网传输数据的工具，它可以利用HTTP、HTTPS、FTP和SFTP等多种协议，从网络服务器传输数据或将数据传输到网络服务器。

除了进行文件传输，我们还可使用 <code>curl命令 从终端发出 HTTP 请求，如 GET 和 POST。这在测试或与网络服务和 API 交互时非常有用。

利用 curl命令，我们可以在不打开浏览器的情况下检查网页内容，因为它可以获取并显示原始数据。

1.2 curl命令的格式

除了 curl --man命令，我们也可以使用curl --help命令获取curl命令的格式和选项说明。

[purpleEndurer @ bash ~]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-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

[purpleEndurer @ bash ~]

curl命令的格式：

curl [选项] <统一资源定位符>

1.3  curl选项说明

curl的选项是目前所学的命令中最多的一个。 

说明中的（H） 表示仅 HTTP/HTTPS，（F） 表示仅 FTP

2 curl命令应用实例

2.1 curl ：显示获取本命令的帮助或手册信息的格式

[purpleEndurer @ bash ~] curl

curl: try 'curl --help' or 'curl --manual' for more information

[purpleEndurer @ bash ~]

 我们可以尝试 使用命令 'curl --help' 或 'curl --manual' 来了解更多信息。

2.2 curl 统一资源定位符：显示指定统一资源定位符的内容（源代码）

这里的 统一资源定位符 可以是网站域名或网页地址。

2.2.1 curl g.cn ： 显示g.cn的源代码

<code>[purpleEndurer @ bash ~] curl g.cn

<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">code>

<TITLE>301 Moved</TITLE></HEAD><BODY>

<H1>301 Moved</H1>

The document has moved

<A HREF="https://google.cn/">here</A>.code>

</BODY></HTML>

[purpleEndurer @ bash ~]

2.1.2 curl www.google.cn：显示 www.google.cn 的源代码。