Unwanted blank after command line <tab> expansion

[Ralf Mardorf]

Maybe readline provides completion commands/shortcuts that are useful.

   $ man bash | grep complete-variable -A1
          complete-variable (M-$)
                 Attempt completion on the text before point, treating it as a shell variable.

This seems to be the meta (Windows) key, the left or right one and perhaps shift+4 for $ on a DE keyboard.
I don't know what to push. Do I need to type a "point" somewhere first?