Which command securely copies files between two hosts over SSH?

• A. scp
• B. ftp
• C. rsync
• D. wget

Answer: (A)

Transferring files securely over SSH relies on encryption and proper authentication. The command designed for this direct secure copy is scp. It uses SSH to protect both the login credentials and the file data as it moves between hosts. With scp you can copy from your local machine to a remote host, copy from a remote host to your machine, or move files between hosts with the right syntax, all over an encrypted SSH connection. For example, scp file.txt user@remote:/path/ transfers a single file securely, and you can copy directories recursively with -r.

While rsync can also operate over SSH and is great for efficient, incremental transfers, the straightforward secure copy task described by the question is best accomplished with scp. FTP sends data in plaintext and is not secure, wget is for downloading from a URL rather than copying between hosts, and rsync, though capable over SSH, is typically used for synchronization rather than a simple one-shot copy.