Uses of SSH Subsytems

Question

SFTP is probably the most widely used "ssh subsystem". This O'Reilly chapter gives some more usage examples; it presents subsytems as "shortcuts" to various commands that can be used.

How do you use this subsytem feature ?

Is there a practical way to limit an ssh key to a subsystem, possibly replacing command restriction option of ssh keys?

Answer 1

A very cool feature that's based on SFTP is sshfs(1):

sshfs -o workaround=all user@remotehost:/ /path/to/localdir

will mount the whole disk at remotehost at the local directory /path/to/localdir . No installation necessary at remotehost,all you need is the sshfs program.