Re: The DISPLAY variable.
peter@easthope.ca wrote:
> Hi,
>
> https://wiki.debian.org/EnvironmentVariables has no mention
> of the DISPLAY variable.
>
> https://www.debian.org/doc/manuals/debian-reference/ch07.en.html
> mentions DISPLAY only incidentally in the last section.
>
> https://www.x.org/archive/X11R6.7.0/doc/X.7.html states,
> "... every X server has a display name of the form:
> hostname:displaynumber.screennumber"
>
> https://en.wikipedia.org/wiki/Environment_variable states,
> "$DISPLAY
> Contains the identifier for the display that X11 programs
> should use by default."
>
> https://wiki.debian.org/Shell states
> "Within Debian, the default /bin/sh shell must be SUSv3/POSIX
> compliant (see debian-policy)."
>
> https://en.wikipedia.org/wiki/Environment_variable#Unix states,
> "if used in front of a program to run, the variables will be
> exported to the environment and thus appear as real environment
> variables to the program:
> VARIABLE=value program_name [arguments]"
>
> Here Debian jessie is running on a machine with two screens
> connected to one video card. Therefore try these commands.
> peter@dalton:~$ DISPLAY=:0.0 program
> peter@dalton:~$ DISPLAY=:0.1 program
> In both cases the program runs in a window opened on the left
> screen. DISPLAY is ignored?
>
> Also try program1.
> peter@dalton:~$ DISPLAY=:0.0 program1
> It runs in a window on the right screen.
>
> peter@dalton:~$ DISPLAY=:0.1 program1
> gives this error.
> "program1: Kernel: Initialized and started.
> Cannot open X11 display :0.1"
>
> peter@dalton:~$ xrandr | grep Screen
> Screen 0: minimum 320 x 200, current 2432 x 960, maximum 4096 x 4096
>
> xrandr recognizes only one screen? Why? Any ideas to have
> the two screens recognized according to the documentation?
>
> Thanks, ... Peter E.
>
In the second case, try
DISPLAY=:1.0 program1
--
Liam
Reply to: