Difference between executing a command and calling a subsystem?

[Damien Miller]

Alex Peuchert wrote:
> Hi everybody,
> just a short question:
> 
> What is the difference between executing a command on a remote machine and
> starting a subsystem via '-s'? And what are the advantages?

Subsystems must be pre-defined in sshd_config. They are intended more as
a sub-protocol extension mechanism (e.g. sftp) than as a user-visible
way to execute commands.

As far as execution of commands go, there is very little difference in
terms of code executed between a defined subsystem and "ssh somehost
command"

-d