与CouchDB通信有两种方式：
CouchDB cURL实用程序用于与CouchDB数据库通信。 此工具用于通过使用支持的协议(HTTP，HTTPS，FTP，FTPS，TFTP，DICT，TELNET，LDAP或FILE)将数据从服务器传输到服务器。 该命令设计为在没有用户交互的情况下工作。 cURL提供了一系列有用的技巧，如代理支持，用户身份验证，FTP上传，HTTP发布，SSL(http:)连接，Cookie，文件传输简历等。
cURL实用程序可用于UNIX，Linux，Mac OS X和Windows等操作系统。 它是一个命令行实用工具，可以直接从命令行中访问HTTP协议。
可以使用cURL实用程序访问任何网站，使用curl命令后跟一个网站地址。
例如：
| curl http://www.web3.xin/ |
cURL实用程序提供了各种选项，可以在cURL实用程序帮助中查看它们。
以下代码显示了cURL帮助的一些部分。
| $ curl --help |
| web3@ubuntu:~$ curl ?help |
| curl: (3) <url> malformed |
| web3@ubuntu:~$ 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) |
| --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 this file |
| --egd-file FILE EGD socket path for random data (SSL) |
| --engine ENGINE 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) |
| --http1.1 Use HTTP 1.1 (H) |
| --http2.0 Use HTTP 2.0 (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 mode (F/POP3) |
| --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 (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 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) |
| --oauth2-bearer TOKEN OAuth 2 Bearer Token (IMAP, POP3, SMTP) |
| -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 |
| --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 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) |
| --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][;OPTIONS] Server user, password and login options |
| --tlsuser USER TLS username |
| --tlspassword STRING TLS password |
| --tlsauthtype STRING TLS authentication type (default SRP) |
| -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 |
| web3@ubuntu:~$ |
可以通过两种方式访问CouchDB的主页：
通过发送GET请求访问CouchDB的主页：首先确保已经在Linux环境中安装了CouchDB并且正在运行成功，使用以下语法将获取请求发送到CouchDB实例。
在命令行下访问CouchDB的主页如下
| web3@ubuntu:~$ curl http://127.0.0.1:5984 |
| {"couchdb":"Welcome","uuid":"22d9e91e925fecdb5a3698e26a7f6815","version":"1.6.1","vendor":{"name":"Ubuntu","version":"14.04"}} |
| web3@ubuntu:~$ |
