write FTP URLs in file name text fields or when using the command line application?

According to the specification of URL formats ( RFC 1738 ), an FTP URL is of the form
ftp://< user>:< password>@< host>:< port>/< url-path>

If you wish to access a FTP server with SSL support, the URL must start with "ftps" instead of "ftp".

Some or all of the parts "< user>:< password>@", ":< password>", ":< port>", and "/< url-path>" may be excluded.

The different components obey the following rules:

user
An optional user name.
password
An optional password. If present, it follows the user name separated from it by a colon.

The user name (and password), if present, are followed by a commercial at-sign "@". Within the user and password field, any ":", "@", or "/" must be encoded.

An empty user name or password is different than no user name or password; there is no way to specify a password without specifying a user name. E.g., <URL:ftp://@host.com/> has an empty user name and no password, <URL:ftp://host.com/> has no user name, while <URL:ftp://foo:@host.com/> has a user name of "foo" and an empty password.

host
The fully qualified domain name of a network host, or its IP address as a set of four decimal digit groups separated by ".". Fully qualified domain names take the form as described in Section 3.5 of RFC 1034 [13] and Section 2.1 of RFC 1123 [5]: a sequence of domain labels separated by ".", each domain label starting and ending with an alphanumerical character and possibly also containing "-" characters. The rightmost domain label will never start with a digit, though, which syntactically distinguishes all domain names from the IP addresses.
port
The port number to connect to. If the port is omitted, the colon is as well.
url-path
The rest of the locator supplies the details of how the specified resource can be accessed. Note that the "/" between the host (or port) and the url-path is NOT part of the url-path.

The url-path of a FTP URL has the following syntax:
< cwd1>/< cwd2>/.../< cwdN>/< name>
Where < cwd1> through < cwdN> and < name> are (possibly encoded) strings. The < cwdx> and < name> parts may be empty. The whole url-path may be omitted, including the "/" delimiting it from the prefix containing user, password, host, and port.

See also