scp - copies files between hosts on a network. It uses ssh for data transfer, and uses the same authentication and provides the same security as ssh. Provided by the openssh-clients package.
sftp - an interactive file transfer program, similar to ftp, but performs all operations over an encrypted ssh channel. It can also use many other features of ssh, such as public key authentication and compression. Provided by the openssh-clients package.
slogin - a symbolic link to the ssh command. Provided by the openssh-clients package.
ssh - the main client program, used for logging into a remote machine and for executing commands on a remote machine. Intended to replace rlogin and rsh, it provides a secure and encrypted channel between two hosts over a network. Also used as a subsystem to other commands listed here. When using ssh, the key exchange and encryption is fully established before credentials (such as username and password) are transmitted. Provided by the openssh-clients package.
ssh-add - adds cryptography and digital signature algorithm (RSA and DSA) identities to the ssh-agent authentication agent. Provided by the openssh-clients package.
ssh-agent - a program to hold private keys used for public key authentication. The idea is that ssh-agent is started in the beginning of a session, and all other windows or programs are started as clients to it. Provided by the openssh-clients package.
ssh-copyid - a script that uses ssh to log into a remote machine and installs your own public key into a remote machine's list of authorized keys. This action provides the ability for future logins with key-based authentication. Provided by the openssh-clients package.
ssh-keygen - a utility that can generate, manage and convert authentication keys. Provided by the openssh package.
ssh-keyscan - a utility for gathering the public ssh host keys of a number of hosts. It can contact several hosts in parallel and is very fast in scanning a collection of hosts for their host keys. Provided by the openssh-clients package.