The question is quite general, because the answer can only be very superficial.
The x-client window geometry is specified in the form ширина x высота + смещение-по-оси-x + смещение-по-оси-y ( x -axis is usually horizontal, y is usually vertical, coordinate +0+0 is usually the upper left corner screen). for example: 100x100+100+100 .
This is described, for example, in $ man X ( GEOMETRY SPECIFICATIONS section ).
but how to transfer this information to the x-client (and whether it is possible to transfer it at all) depends on the client itself.
for example, the gnome-terminal and xfce-terminal programs (like many other x clients) have the option --geometry=значение :
$ gnome-terminal --geometry=100x100+100+100
and the xterm program has the option -geometry значение
$ xterm -geometry 100x100+100+100
In addition to the above, it is worth mentioning:
- about the file
~/.Xresources ( ~/.Xdefaults ) and the xrdb program, which can be used by de / wm to load various resources, including instructions on the geometry of a window; - about the fact that de / wm can make independent decisions about the location of the created windows, ignoring the wishes of the program creating the window.