If I use PuTTY, I log in with a ppk RSA key file. Then I use "sudo su - userid" to change to the higher privileged user. When I do that command, I do NOT have to enter a password.
So, for the SFTP setting, there is a sample that reads like
"su -c /bin/sftp-server" so that's missing the userid and the sudo
There is a popular link on StackOverflow that shows:
"sudo su -c /usr/lib/sftp-server" which is still missing the userid
I though it might be a formatting problem, so I created a script with just
sudo su - userid /usr/lib/sftp-server
So my question is: Can I do the equivalent of "sudo su - userid" and then launch sftp-server?