5.2.2.6 -sftp, -scp force use of particular protocol

As mentioned in section 5.2.1, there are two different file transfer protocols in use with SSH. Despite its name, PSCP (like many other ostensible scp clients) can use either of these protocols.

The older SCP protocol does not have a written specification and leaves a lot of detail to the server platform. Wildcards are expanded on the server. The simple design means that any wildcard specification supported by the server platform (such as brace expansion) can be used, but also leads to interoperability issues such as with filename quoting (for instance, where filenames contain spaces), and also the security issue described in section 5.2.1.

The newer SFTP protocol, which is usually associated with SSH-2 servers, is specified in a more platform independent way, and leaves issues such as wildcard syntax up to the client. (PuTTY's SFTP wildcard syntax is described in section 6.2.2.) This makes it more consistent across platforms, more suitable for scripting and automation, and avoids security issues with wildcard matching.

Normally PSCP will attempt to use the SFTP protocol, and only fall back to the SCP protocol if SFTP is not available on the server.

The -scp option forces PSCP to use the SCP protocol or quit.

The -sftp option forces PSCP to use the SFTP protocol or quit. When this option is specified, PSCP looks harder for an SFTP server, which may allow use of SFTP with SSH-1 depending on server setup.