Screen sharing using command line

[sul]

Hi,

I recently installed Ubuntu LTS 20.04.02 and was able to turn on Screen Sharing under Settings using the GUI--works well. However, is there a way to do this using command line, rather than GUI?

thank you,

-sul

[kckit]

never mind

[ActionParsnip]

Did you resolve the issue? If so can you please share the solution as it may help others

[TheFu]

Use x2go if you want a remote desktop. https://wiki.x2go.org/doku.php/doc:usage:desktop-sharing

Use tmux or screen if you want to share a terminal with other people.
https://www.howtoforge.com/sharing-terminal-sessions-with-tmux-and-screen

[sul]

no resolution as yet. I am still waiting on an answer to the question.

[sul]

thanks for the tip. x2go client is very unstable on windows 10. session opens a black screen and simply closes--no error message is displayed.

[scorp123]

thanks for the tip. x2go client is very unstable on windows 10.

Can't confirm this at all, I use it daily. Did you properly configure both sides (e.g. "x2goserver" is installed + running on the Linux side) and e.g. select a desktop environment that's installed on the Linux side?

[scorp123]

However, is there a way to do this using command line, rather than GUI?

Totally NOT RECOMMENDED method because this relies on an unsafe and easy hackable protocol (VNC), but if you have the GNOME desktop you can try this command:

/usr/lib/vino/vino-server --display=:0

It should default to the settings you have defined previously, e.g. when you activated it using the desktop.

[sul]

Totally NOT RECOMMENDED method because this relies on an unsafe and easy hackable protocol (VNC), but if you have the GNOME desktop you can try this command:

/usr/lib/vino/vino-server --display=:0

It should default to the settings you have defined previously, e.g. when you activated it using the desktop.

Thank you but no joy for me. it results in error:


Unable to init server: Could not connect: Connection refused
Cannot open display: :0

I'm using ssh (putty) on my windows pc. Looks like vino requires logging into the desktop environment of the physical machine for this command to work. Unfortunately, this doesn't help my situation.

-sul.

[TheFu]

Thank you but no joy for me. it results in error:


Unable to init server: Could not connect: Connection refused
Cannot open display: :0

I'm using ssh (putty) on my windows pc. Looks like vino requires logging into the desktop environment of the physical machine for this command to work. Unfortunately, this doesn't help my situation.

-sul.

With x2go, you don't need putty. Also, the x2goclient accepts pointing at a profile, which can be configured using ssh-keys (use the x2go version, not putty's version) for trusted connections. I've never used Win10, but on prior versions, x2go was solid for weeks. I'd be surprised if that wasn't still the situation. Leads me to think there is an issue on your system or a fundamental misunderstanding about how things need to be setup.

After using x2go, very few people would want to return to using RDP or VNC-based tools if they don't have other mandates. x2go is much faster and can be tuned for the speed of the network and both systems.

[sul]

Can't confirm this at all, I use it daily. Did you properly configure both sides (e.g. "x2goserver" is installed + running on the Linux side) and e.g. select a desktop environment that's installed on the Linux side?

Thanks. I followed instructions carefully on x2go wiki. I'm on a default install of ubuntu 20.04 LTS with Gnome desktop and so I'm selecting GNOME on the client. The client goes through the motions of authenticating with the server and opens a black window followed by a splash screen that looks like a large X2GO sign for about a second and then the window simply closes.

Thanks!

-s.

[TheFu]

Gnome3 is very bloated and really, really, wants direct hardware access to the GPU, IME. Best to use **any** other DE or just use a Window Manager setup instead. Other DEs - XFCE, LXQt, KDE, Mate, Cinnamon, ....

Also, in the profile for the connection inside the x2go-client, ensure that the DE/WM used is selected.
Also, it is best to have ssh-keys already setup between the client and the server before using x2go. This will allow password-less connections, except to unlock the ssh keys first thing in the morning.

[sul]

Gnome3 is very bloated and really, really, wants direct hardware access to the GPU, IME. Best to use **any** other DE or just use a Window Manager setup instead. Other DEs - XFCE, LXQt, KDE, Mate, Cinnamon, ....

Also, in the profile for the connection inside the x2go-client, ensure that the DE/WM used is selected.
Also, it is best to have ssh-keys already setup between the client and the server before using x2go. This will allow password-less connections, except to unlock the ssh keys first thing in the morning.

Thanks! I appreciate the advice. Unfortunately, at this time I prefer something that works well with Gnome3. Hopefully x2go will get there someday soon--I think it's got a lot of promise otherwise.

best-

-s

[TheFu]

Thanks! I appreciate the advice. Unfortunately, at this time I prefer something that works well with Gnome3. Hopefully x2go will get there someday soon--I think it's got a lot of promise otherwise.

best-

-s

Doubtful. It is a gnome issue, not x2go. Actually, I just setup a minimal 21.04 gnome system 3 days ago. With Spice protocol, it flies, but spice only works for KVM VMs, not on physical hardware. I'll try x2go ...

sudo apt install x2goserver
from an 18.04 x2goclient ... the connection worked, but there was a GUI failure. Looks like Wayland is the problem. Confirmed. Seems wayland doesn't like x2go. Disabled wayland https://linuxconfig.org/how-to-enable-disable-wayland-on-ubuntu-20-04-desktop and my WM login works, but Gnome still does not.

If you are set on Gnome3 ... Screen Sharing is clearly running a program with some options. .desktop files are the normal way for menu programs. Those are just text files. Find the one used in the menu, look inside for the command. I couldn't find that program on 21.04 and don't know how to use gnome DE to figure it out. sorry for my ignorance.

$ locate .desktop |grep -i shari
/etc/xdg/autostart/org.gnome.SettingsDaemon.Sharing.desktop
/usr/share/applications/gnome-sharing-panel.desktop
is all I found. Alas, I have a minimal install.
https://help.gnome.org/users/gnome-help/stable/sharing-desktop.html.en

[scorp123]

If you are set on Gnome3 ... Screen Sharing is clearly running a program with some options.

See my post above. GNOME is using "vino", which is essentially a VNC server.


> apt info vino
Package: vino
Version: 3.22.0-5ubuntu2.2
Priority: optional
Section: gnome
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian GNOME Maintainers <pkg-gnome-maintainers@lists.alioth.debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 414 kB
Depends: libavahi-client3 (>= 0.6.16), libavahi-common3 (>= 0.6.16), libavahi-glib1 (>= 0.6.16), libc6 (>= 2.15), libcairo2 (>= 1.10.0), libgcrypt20 (>= 1.8.0), libglib2.0-0 (>= 2.37.3), libgnutls30 (>= 3.6.12), libgtk-3-0 (>= 3.0.0), libice6 (>= 1:1.0.0), libjpeg8 (>= 8c), libminiupnpc17 (>= 1.9.20140610), libnotify4 (>= 0.7.0), libsecret-1-0 (>= 0.7), libsm6, libx11-6, libxdamage1 (>= 1:1.1), libxext6, libxfixes3, libxtst6, zlib1g (>= 1:1.1.4), dconf-gsettings-backend | gsettings-backend
Recommends: gvfs
Suggests: gnome-control-center
Breaks: gnome-control-center (<< 1:3.13.2)
Homepage: https://wiki.gnome.org/Projects/Vino
Task: ubuntu-desktop, ubuntu-budgie-desktop
Download-Size: 126 kB
APT-Manual-Installed: no
APT-Sources: http://ch.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
Description: VNC server for GNOME
VNC is a protocol that allows remote display of a user's desktop. This
package provides a VNC server that integrates with GNOME, allowing you
to export your running desktop to another computer for remote use or
diagnosis.


> dpkg -L vino
/.
/usr
/usr/lib
/usr/lib/systemd
/usr/lib/systemd/user
/usr/lib/systemd/user/vino-server.service
/usr/lib/vino
/usr/lib/vino/vino-server
/usr/share
/usr/share/applications
/usr/share/applications/vino-server.desktop
/usr/share/doc
/usr/share/doc/vino
/usr/share/doc/vino/AUTHORS
/usr/share/doc/vino/NEWS.gz
/usr/share/doc/vino/README
/usr/share/doc/vino/changelog.Debian.gz
/usr/share/doc/vino/copyright
/usr/share/glib-2.0
/usr/share/glib-2.0/schemas
/usr/share/glib-2.0/schemas/org.gnome.Vino.enums.xml
/usr/share/glib-2.0/schemas/org.gnome.Vino.gschema.xml

And you can trigger it from the command line if you are already logged in, otherwise you'll run into an error about display :0 :

/usr/lib/vino/vino-server --display=:0

The package list mentions a "vino-server.service" for "systemd". Content of that file looke like this:

[Unit]
Description=Vino VNC server

[Service]
Type=dbus
BusName=org.gnome.Vino
ExecStart=/usr/lib/vino/vino-server
Restart=on-abnormal

That thing doesn't work though. But maybe it would be possible to get it working? I don't know.

There used to be instructions around the web like this one:
https://www.jakeyoon.com/2008/11/19/enable-vino-vnc-server-for-login-manager-gdm-in-ubuntu/

... that would show you how to manually enable "vino-server" for GDM. But as far as I know GNOME was changed a lot and those instructions very likely no longer work.

So I wonder if there's a new way to get "vino-server" to work?

The other traditional way to have your GDM/ LightDM inside a VNC session would be to get "x11vnc" to work, as per:
https://help.ubuntu.com/community/VNC/Servers#Have_x11vnc_automatically_start_in_Ubuntu

Again, not sure if those instructions still work.

[scorp123]

Thanks! I appreciate the advice. Unfortunately, at this time I prefer something that works well with Gnome3.

I will very likely be heavily criticised for this ... but are commercial + free-for-private-use solutions an option for you? I think at this point something like AnyDesk would be easier for you to use.

Warning:

please be aware that AnyDesk makes every of your computers it is installed on REACHABLE on the Internet. In other words: People getting hacked, scammed and having their bank account, Amazon account etc. invaded is not unheard of. Your firewall WILL NOT protect you in this case because AnyDesk is designed to work around firewalls.

But yes, sure ... it is super easy to use.

Security advice you absolutely must follow so you don't get hacked via AnyDesk:


never ever share any of your AnyDesk ID's with anyone!! (forum posts, screenshots, social media, etc. )
select strong + complex passwords that are very hard to guess (use a "password generator" if need be!)
Enable 2-Factor Authentication. The mechanism is there, it just needs to be enabled. Don't skip this!!


With that out of the way:

AnyDesk installation via DEB repository:
http://deb.anydesk.com/howto.html

All commands listed there need to be executed as "root", e.g. you have to use "sudo" with every command they list above.

General installation instructions:
https://support.anydesk.com/Installation

Information that Wayland needs to be disabled for AnyDesk:
https://support.anydesk.com/AnyDesk_on_Linux

The most important part: 2-Factor Authentication. DON'T SKIP THIS.
https://support.anydesk.com/Two-Factor_Authentication

But yes, this is super easy to use and it works with GNOME 3.x too.

Now I need to wash my hands, I feel dirty :neutral: