How to Xephyr ~ AKA Multiple, nested X sessions

[wall0645]

Yes!! I figured it out! This is super cool! Thank you bunches bodhi.zazen! METTA

[sexcopter]

Forward a xterm:

ssh -XfC -c blowfish user@server xterm

• -X = forward X
• -f = puts your ssh session into the background
• -C = use compression -c blowfish = use blowfish (I am told this is the fastest)

I just saw this an wanted to make this clear. -C gives compression (no choice of method, uses gzip), -c blowfish specifies a particular cipher protocol (nothing to do with compression), and isn't really necessary, since suitable ciphers are invoked anyway.

I got all this from the man page for ssh.

Also, I read somewhere else that while compression is good for low bandwidth situations, on high-speed connections it's actually leads to a performance hit.

Cheers,

James

[Dr Small]

Dr Small, I have modified your script a bit to make it so you can enter your own screen resolution (instead of clicking on pre-defined ones). Here is the new script, in case anyone else wants it.

Instead of using zenity for popups, I've strictly rewritten it for prompts in the terminal. It is much simplier this way, I think

#!/bin/bash
# 
# GTK-Xephyr
# by Dr Small <drsmall@mycroftserver.homelinux.org>
# Simplifies the process of using Xephyr
#
# Dependencies:
#		Xephyr
	


echo ''
echo 'Select screen resolution'
echo '[1] 640x480'
echo '[2] 800x600'
echo '[3] 1024x768'
echo '[4] USER SPECIFIED'
echo '[5] EXIT'
echo ''
read resolution

case $resolution in
	1)
	resolution='640x480'
	;;

	2)
	resolution='800x600'
	;;

	3)
	resolution='1024x768'
	;;

	4)
	echo 'Please enter a screen resolution:'
	read manualresolution
	resolution=$manualresolution
	;;

	5)
	exit
	;;
esac


echo ''
echo 'Display Number:'
echo '(Please choose a number higher than 0)'
read display


echo ''
echo 'Command:'
echo '(Specify a command to be executed on the nested window)'
read command


echo ''
echo 'Starting Xephyr with resolution of '$resolution
echo 'on display number '$display
Xephyr -ac -screen $resolution -br 2> /dev/null :$display&

echo ''
echo 'Switching to display number '$display
export DISPLAY=:$display

$command&
exit 0

[Wiebelhaus]

This is freaking amazing!

Thanks!

[shafin]

I just ran in xephyr into opensolaris (it comes preinstalled) and it looks great.

[mk_cafe]

I just want to ask what's the difference if i set Xephyr on my local computer and then connect to remote computer by ssh with X11 forwarding and when i just set Xephyr by ssh on remote computer? I mean something like this:

1:

Xephyr :1 &
DISPLAY=:1
ssh -X user@hostname
xeyes

2:

ssh -X user@hostname
Xephyr :1 &
DISPLAY=:1
xeyes

If i am thinking right in 1st ex. we are setting Xephyr server to catch any app we start , so when we connect through ssh to remote computer and run any app then it's forwarded to default display on our local comp. which is actually Xypher window?

And in second ex. we just login to remote computer and set Xephyr the same way, but when we run some application there it's forwarded to Xephyr window on remote comp. and this window is forwarded to our local machine?

If so, are there any differences like the way data is sending between computers etc.?

Sorry if i wrote this unclear but i am just curious and i'm trying to get it

[maestrobwh1]

This was working in intrepid, but I lost my partition and installed Karmic and re-found my answer in post #24 here to try to get this to work again, as I am getting an error. Basically I want to run the app XnView in Xephyr on the same machine, as for some reason, the app is transparent on the kde 4 desktop so images are not rendered properly. No special window settings seem to fix this, but running in Xephyr makes it look proper:

#!/bin/bash
# xnview.sh to launch xnview in xephyr
Xephyr -ac -screen 1024x768 -br -reset -terminate :1.0 &
export DISPLAY=:1.0
xnview
exit 0

but I get a 1024x768 black screen and this output:

$ sh xnview.sh
[dix] Could not init font path element /usr/share/fonts/X11/cyrillic, removing from list!
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
unrecognised device identifier!
(EE) config/hal: NewInputDeviceRequest failed (2)
XIO: fatal IO error 11 (Resource temporarily unavailable) on X server ":0.0"
after 48 requests (46 known processed) with 0 events remaining.
** XnView v1.70 Copyright 1991-2005 Pierre-E Gougelet (Sep 6 2005/15:28:24) **
Version for Linux x86/Motif (All rights reserved)
** This is freeware software (for non commercial use)

Type xnview -help, for more information
Error: Can't open display: :1.0
$

The app does open by itself.

[bodhi.zazen]

Karmic is in alpha right now so you may wish to file a bug report.

[Snowhog]

@bodhi.zazen

Back when, like when I was using Intrepid - I used Xephyr to capture the KDM (yes, KDE) Login screen. Then, the command was:

Xephyr -query localhost -screen 800x600 :1

I'm now using Karmic 9.10 (Kubuntu). The same two files - kdmrc and Xaccess have been properly edited. The command above doesn't work - the syntax for Xephyr has changed - and after Googling, found that this command:

Xephyr :1 -query localhost -host-cursor -screen 1024x768

should work. It does, but I just get a black screen window of the specified size with a working mouse.

What command syntax do I have to issue in order to get the KDM Login screen? I just want to be able to take a screen shot of my custom KDM Login screen. As stated, back in Intrepid, the 'old' syntax did the trick, but now ...

Thank you.

[Snowhog]

Got it!

Xephyr :1 -query 127.0.0.1 -screen 1024x768

You have to use the localhost IP address instead of 'localhost' and it works. My KDM Login Screen came up and I was able to take my snapshot of it.

Cool.