I was reading about OpenSSH and I have the following questions:

  1. What is the difference between ssh and slogin?

  2. What is the difference between scp and sftp?

  3. Does sshd (on server side) provide separate server processes to handle each client (ssh, slogin, sftp, scp) type requests or just one process for all client types?

  4. is the secure shell a standalone shell like bash etc., or just a process that encrypt/decrypts traffic and communicate to ordinary bash process locally?

closed as too broad by muru, mosvy, Stephen Kitt, Jeff Schaller Jul 3 at 22:43

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • All of these questions should be easily answerable by reading the relevant manuals, and by some simple testing. – Kusalananda Jun 29 at 22:02

Since the questions are listed, I'll list the respective answers:

  1. slogin is an alias for ssh (they are the same) further reading
  2. scp and sftp do similar things in that they transfer files, but scp is a separate program that uses ssh to copy files. sftp is an extension of ssh itself that transfers files similar to FTP, but over ssh further reading
  3. Yes, the sshd spins up a separate process for each connection. This can be verified by connecting multiple times to an ssh server and then doing ps aux | grep ssh on the server
  4. ssh is a protocol, not a shell. It gives access to the shell on the other side and encrypts the traffic between

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