Conspy allows a (possibly remote) user to see what is displayed on a Linux virtual console, and send keystrokes to it. It works with Linux and FreeBSD, as far as I know.
It is rather like VNC, but where VNC takes control of a GUI conspy takes control of a text mode virtual console. Unlike VNC, conspy does not require a server to be installed prior to being used.
Sparse. There is a man page, a change log and a README.
Q: Can conspy look at other types of terminals, such as a normal serial terminal, or a pty such as a telnet session?
A: No. Nor will it ever be able to do so. Conspy does not intercept the character stream being sent to the virtual console. If it did that it would have to interpret all the ANSI escape sequences understood by the Linux virtual console exactly the same way Linux does. That would be tedious, and would break each time Linux changes the escape sequences. Instead conspy asks the Linux kernel for the virtual console's frame buffer. That is, it gets an image of what is displayed on the screen and makes your terminal look the same. There is no way to do that for other tty's. If conspy was to work with them it would have to interpret the character stream as it passes through the tty. This is well neigh impossible because there are many different types of terminal out there and they all use different escape sequences. If all you all to do it look at the raw character stream as it passes through the tty look up ttysnoop on Freshmeat.
Conspy is copyright © 2005,2006,2007,2009,2011,2014,2015 Russell Stuart. It is licensed under the GNU Affero General Public License.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
The copyright holders grant you an additional permission under Section 7 of the GNU Affero General Public License, version 3, exempting you from the requirement in Section 6 of the GNU General Public License, version 3, to accompany Corresponding Source with Installation Information for the Program or any work based on the Program. You are still required to comply with all other Section 6 requirements to provide Corresponding Source.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
Development for conspy is hosted on Source forge:
Russell Stuart, 2014-May-27.