pe...@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