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. -- 123456789 123456789 123456789 123456789 123456789 123456789 123456789 Tel +1 360 639 0202 http://easthope.ca/Peter.html Bcc: peter at easthope. ca
