Research

From Official Ubuntu Documentation: Share your desktop we get that it usages Vino. We should be able to manipulate setting from terminal with gsettings.

Development

Let's try that and see desktop share (Vino) status:

sudo gsettings list-recursively org.gnome.Vino

If we check the disabled state:

org.gnome.Vino notify-on-connect true
org.gnome.Vino alternative-port uint16 5900
org.gnome.Vino disable-background false
org.gnome.Vino use-alternative-port false
org.gnome.Vino icon-visibility 'client'
org.gnome.Vino use-upnp false
org.gnome.Vino view-only true
org.gnome.Vino prompt-enabled true
org.gnome.Vino disable-xdamage false
org.gnome.Vino authentication-methods ['none']
org.gnome.Vino network-interface ''
org.gnome.Vino require-encryption false
org.gnome.Vino mailto ''
org.gnome.Vino lock-screen-on-disconnect false
org.gnome.Vino vnc-password '1234'

In enabled state:

org.gnome.Vino notify-on-connect true
org.gnome.Vino alternative-port uint16 5900
org.gnome.Vino disable-background false
org.gnome.Vino use-alternative-port false
org.gnome.Vino icon-visibility 'client'
org.gnome.Vino use-upnp false
org.gnome.Vino view-only false
org.gnome.Vino prompt-enabled false
org.gnome.Vino disable-xdamage false
org.gnome.Vino authentication-methods ['vnc']
org.gnome.Vino network-interface ''
org.gnome.Vino require-encryption false
org.gnome.Vino mailto ''
org.gnome.Vino lock-screen-on-disconnect false
org.gnome.Vino vnc-password '1234'

Let's find the difference with diff between disabled enabled:

7,8c7,8
< org.gnome.Vino view-only true
< org.gnome.Vino prompt-enabled true
---
> org.gnome.Vino view-only false
> org.gnome.Vino prompt-enabled false
10c10
< org.gnome.Vino authentication-methods ['none']
---
> org.gnome.Vino authentication-methods ['vnc']

So in theory to enable we need to do the following:

sudo gsettings set org.gnome.Vino notify-on-connect false
sudo gsettings set org.gnome.Vino view-only false
sudo gsettings set org.gnome.Vino prompt-enabled false
sudo gsettings set org.gnome.Vino authentication-methods "['vnc']"
sudo gsettings set org.gnome.Vino vnc-password '1234'

It doesn't change the settings, more over gsettings over ssh don't work: https://stackoverflow.com/a/58222395. work around!?:

sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino notify-on-connect false'
sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino view-only false'
sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino prompt-enabled false'
sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino authentication-methods "['vnc']"' //errors out
sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino vnc-password '1234''

This errors out at 4th command. Let's pause for today!

---

Update: Apr 24, 2020

Development

We will pick up from where we left. To fix the error in the 4th command do:

sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino authentication-methods [\"vnc\"]'

Yes! We can change the setting from terminal over SSH. The commands above has changed the Screen Share setting to put a check mark on Allow connections to control the screen and toggled the radio button from New connections must ask for access to Require a password but the password field is empty. 🤦‍♂️ So this somewhat works but need more work. Maybe we confues the command with nesed ' and the begaining of the password with ' ended the command and took a empty password. Let's encode the password with and " and escape the " with \:

sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino vnc-password \"1234\"'

This doesn't work as well nor " without \ and just the text 1234. While reading more on it I found this: https://askubuntu.com/a/12195 where it say the password is base64 encoded. Let's test this with simple base64 encoded password, 1234. We can encode the password, 1234 with the base64 tool like this:

echo -n 1234 | base64

The output is:

MTIzNA==

Now if we replace 1234 with the base64 encoded string, we get:

udo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino vnc-password MTIzNA=='

This works!! Let's automate the base64 encoding and reduce one step:

sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings set org.gnome.Vino vnc-password $(echo -n 1234 | base64)'

Now if we change the password all we have to do is replace the 1234 in this command. We are one step closer to finish this. Now all we need is to toggle the Screen Sharing button on.

After spending a long time in web search and reading forum post I get to the conclusion that that is not meant to be done via CLI and settled for a solution that came with the answer regarding password (https://askubuntu.com/a/12195) which is running the Vino server manually from the terminal:

/usr/lib/vino/vino-server

If we are using SSH, the -X flag of openssh-client must be used which Enables X11 forwarding or we will the following error:

Unable to init server: Could not connect: Connection refused
Cannot open display:
Run 'vino-server --help' to see a full list of available command line options

Now let's try to connet to our remote machine with Remmina. We will do the following:

• open Remmina

• click the plus button at the top left

• give a identifiable name in the Name field

• select VNC - Virtual Network Computing from Protocol drop down list

• put remove machine IP address in the Server field

• optionally, put the password in clear text ie. 1234 in User password field, if not it would we will be prompted for password every time we connect.

• now click on Save and Connect

It is surely taking a bit time to connect. We can see the log in our remote machine terminal where we start the Vino server. After a while we see it connect but what is this? We are seeing the client machine screen not the remote one! I am guessing this is problem with the X Server DISPLAY variable. Let's export this and try to start the server again:

export DISPLAY=:0

Now we can see our remote machine's desktop screen.

We still have one caveat that is when we connect to the remote machine it shows a notification:

Another user is controlling your desktop
A user on the computer '$IP' is remotely controlling your desktop.

We can reset all changes done with gsettings with:

sudo su $USER -s /bin/bash -c 'XDG_RUNTIME_DIR=/run/user/$UID DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$UID/bus gsettings reset-recursively org.gnome.Vino'

Source

• GNOME Wiki!: Using GSettings:

• https://askubuntu.com/questions/304017/how-to-set-up-remote-desktop-sharing-through-ssh

• https://www.howtogeek.com/429190/how-to-set-up-remote-desktop-on-ubuntu/

• https://askubuntu.com/questions/4474/enable-remote-vnc-from-the-commandline#22354

• https://help.ubuntu.com/community/VNC/Servers

• https://askubuntu.com/questions/4474/enable-remote-vnc-from-the-commandline

• https://wiki.archlinux.org/index.php/Vino