Set your local display variable and if the ports are open and OpenX is
running, you will get an echoed Xterminal session to open locally. If you
are using Windows locally, you will need an Xcapable SSH client like
Hummingbird.
An X program needs two pieces of information in order to connect to an X
display.
-
It needs the address of the display, which is typically :0 when you're
logged in locally or :10, :11, etc. when you're logged in remotely (but
the number can change depending on how many X connections are active). The
address of the display is normally indicated in the DISPLAY environment
variable.
-
It needs the password for the display. X display passwords are called *magic
cookies*. Magic cookies are not specified directly: they are always
stored in X authority files, which are a collection of records of the form
“display :42 has cookie 123456”. The X authority file is normally
indicated in the XAUTHORITY environment variable. If $XAUTHORITY is not
set, programs use ~/.Xauthority.
You're trying to act on the windows that are displayed on your desktop. If
you're the only person using your desktop machine, it's very likely that
the display name is :0. Finding the location of the X authority file is
harder, because with gdm as set up under Debian squeeze or Ubuntu 10.04,
it's in a file with a randomly generated name. (You had no problem before
because earlier versions of gdm used the default setting, i.e. cookies
stored in ~/.Xauthority.)
Getting the values of the variables
Here are a few ways to obtain the values of DISPLAY and XAUTHORITY:
-
You can systematically start a screen session from your desktop, perhaps
automatically in your login scripts (from ~/.profile; but do it only if
logging in under X: test if DISPLAY is set to a value beginning
with :(that should cover all the cases you're likely to encounter)).
In
~/.profile:
case $DISPLAY in
:*) screen -S local -d -m;;
esac
Then, in the ssh session:
screen -d -r local
-
You could also save the values of DISPLAY and XAUTHORITY in a file and
recall the values. In ~/.profile:
case $DISPLAY in
:*) export | grep -E ' (DISPLAY|XAUTHORITY)='
>~/.local-display-coordinates.sh;;
esac
In the ssh session:
. ~/.local-display-coordinates.sh
screen
-
You could detect the values of DISPLAY and XAUTHORITY from a running
process. This is harder to automate. You have to figure out the PID of a
process that's connected to the display you want to work on, then get the
environment variables from /proc/$pid/environ (eval export
$(</proc/$pid/environ tr \\0 \\n | grep -E '^(DISPLAY|XAUTHORITY)=')¹).
Copying the cookies
Another approach is to not try to obtain the value of $XAUTHORITY in the
ssh session, but instead to make the X session copy its cookies into
~/.Xauthority. Since the cookies are generated each time you log in, it's
not a problem if you keep stale values in ~/.Xauthority.
There can be a security issue if your home directory is accessible over NFS
or other network file system that allows remote administrators to view its
contents. They'd still need to connect to your machine somehow, unless
you've enabled X TCP connections (Debian has them off by default). So for
most people, this either does not apply (no NFS) or is not a problem (no X
TCP connections).
To copy cookies when you log into your desktop X session, add the following
lines to ~/.xprofile or ~/.profile (or some other script that is read when
you log in):
case $DISPLAY:$XAUTHORITY in
:*:?*)
# DISPLAY is set and points to a local display, and XAUTHORITY is
# set, so merge the contents of `$XAUTHORITY` into ~/.Xauthority.
XAUTHORITY=~/.Xauthority xauth merge "$XAUTHORITY";;
esac
¹ In principle this lacks proper quoting, but in this specific instance
$DISPLAY and $XAUTHORITY won't contain any shell metacharacter.
On Sun, Jul 22, 2012 at 1:03 PM, Joseph Sinclair
<
plug-discussion@stcaz.net>wrote:
> The closest to your old rlogin approach would be "ssh -X
> yourserver.ip.address <x program to run, e.g. meld>" you might need to
> fiddle with some settings to get it working, however.
>
> On 07/22/2012 12:56 PM, Stephen wrote:
> > ssh transfers i think would be the fastest/easiest. there are some gui
> > clients that can do this.
> >
> > On Sun, Jul 22, 2012 at 12:55 PM, Wayne Davis
> > <waydavis.phx.lists@gmail.com> wrote:
> >> Ok,
> >>
> >> Years ago, when i worked for frontier global-center, I remember that we
> >> could "rlogin" to a system and "Startx". At least I REMEMBER it this
> way.
> >> My recollection was that I was running the GUI LOCALLY and metatdata was
> >> being transferred across. VERY fast & efficient screens.
> >>
> >> A: AM I recalling wrongly?
> >> B: I'm wanting to set up a server box on my network for files, music,
> >> video that will be headless (No monitor or mouse connected)
> >>
> >> Running Kubuntu 12.04 as primary OS on all boxes here.
> >> I see rlogin, ssh, blah blah blah.......
> >>
> >>
> >> I'm looking for EFFICIENT GUI presentation, File transfers.
> >>
> >> xvnc11 works but is slow, teamviewer is making connections outside my
> >> network to operate AND is wine based :-(
> >>
> >> What should I use that will keep it S I M P L E (if possible) and
> secure (
> >> I am behind a M0n0wall WRAP firewall) I want to be able to connect at
> will.
> >>
> >>
> >> Is this going to be a major pain?
> >>
> >>
> >> Thanks everyone for your thoughts :-)
> >>
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> >
> >
> >
>
>
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