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## 1 Getting Started

Uniform Resource Locators (URLs) are a specific form of Uniform Resource Identifiers (URI) described in RFC 2396 which updates RFC 1738 and RFC 1808. RFC 2016 defines uniform resource agents.

URIs have the form scheme:scheme-specific-part, where the schemes supported by this library are described below. See Supported URL Types.

FTP, NFS, HTTP, HTTPS, `rlogin`, `telnet`, tn3270, IRC and gopher URLs all have the form

         scheme://[userinfo@]hostname[:port][/path]

where ‘`[`’ and ‘`]`’ delimit optional parts. userinfo sometimes takes the form username:password but you should beware of the security risks of sending cleartext passwords. hostname may be a domain name or a dotted decimal address. If the ‘`:port`’ is omitted then the library will use the `well known' port for that service when accessing URLs. With the possible exception of `telnet`, it is rare for ports to be specified, and it is possible using a non-standard port may have undesired consequences if a different service is listening on that port (e.g., an HTTP URL specifying the SMTP port can cause mail to be sent). The meaning of the path component depends on the service.