Hello everyone,

I am working on a laptop with Ubuntu 19.04 installed.
I have an older computer running with Xubuntu 4.15.
I wish to use the Xubuntu screen as monitor for the Ubuntu computer.

I have tried to link the devices with VGA cable, but found out it could only take input and not output.
I have tried to share screen with xhost, but can't make it work.

Would anyone have a good tutorial, a reference documentation, or a tool to use a computer screen as a monitor?

Thanks for the help!

Most laptops have an external monitor port. If you are not using the desktop then directly connect the monitor to the laptop.

If you are using the desktop to there are ways to extend the laptops desktop over the network to the desktop.

https://wiki.archlinux.org/index.php/Extreme_Multihead

Thanks for the answer.

Do you mean the VGA port in this case?

As I quote, I have linked the two computers with a VGA cable, and tried to find a way to use the second one as a monitor. The option does not exist.

I think xrandr is nice if you have indeed several monitors, but it does not manage computer screens.

What desktop software are you using? KDE? Xfce? twm? (ha ha, kidding 'bout that last one)

You might need to go into your system configuration GUI's "Display" dialog to enable the external monitor. There may also be a function key that switches between the laptop display and the externally-connected monitor. Back when I connected the VGA connection of my LCD monitor to my old Dell and/or work Thinkpad, I had no difficulty having it recognized by Linux. As this was probably in the OpenSUSE 12.x or 13.x days---I can only imagine it being easier nowadays. Also, depending on your external monitor, you may need to go into an on-screen menu to select which video connection is the active one, especially if it's already in use on a desktop system. (My Asus monitor requires this if it senses video on, say, the HDMI connection as well as the VGA connection.)

Good luck...

I’m reading the OP as wanting to connect the monitor to both systems, and switch between them.

If that’s correct, then shop for a vga switch. I’ve not looked, but it’s the V part of a KVM switch, so there’s probably something out there.
Alternatively, move the ‘puter end of the cable when needed manually.

If I’m wrong, the OP is going to need to clarify.

I am trying to understand what you are trying to accomplish but I guess I am confused by your language.

VGA ports are one directional from the computer connected to monitor. You can not plug a VGA cable from one computer to another.

I am not sure what you mean by monitor versus computer screen. A laptop basically a built in monitor that is called a screen.

With two monitors connected to the same computer you can extend your desktop so they appear as one two different desktops.

My second suggestion that I have not personally used that can extend a desktop from one computer to another using the LAN network.