If you start wish interactively and type:

puts [wm geometry .]

you will get something like:

200x200+90+90

The actual numbers may vary depending on X11 defaults, window managers,
etc. If you put the same thing in a script, though:

#!/usr/local/bin/wish
puts [wm geometry .]

You will instead get this:

1x1+0+0

This will happen because you are requesting geometry information before
the window has actually been drawn.  In general, before you start asking
about window sizes, use the `update` command so that the geometries of
the windows can be resolved.  Changing the above script to this will
give the expected results:

#!/usr/local/bin/wish
update
puts [wm geometry .]