Data output from CP2K

[Ondrej Marsalek]

Dear developers,

I have a bugreport / feature request related to the way CP2K handles
file output.

I have a setup that I use for all my runs that makes sure that there
is always an up-to-date restart file and wavefunction restart at the
end of an MD step. It works well for any continuation, with one
exception. If there is a cube file written for the MD step that is
last in one run and therefore first in the restart, the cube file is
written again in the restart and it is appended to the same file.
Therefore, you get an invalid data file (disregarding the
non-existence of a specification for the cube file format) in an
otherwise correct run. I would probably call this a bug.

In general it would be nice to have any files that get overwritten
backed up first. Appending is of course not a problem for file formats
where it makes sense (xyz, ener, ...). In other cases (like a cube
file), I'd rather see a backup of the old file and a creation of a new
one, rather than having the old file overwritten or appended to.

Thank you for considering this.

Best regards,
Ondrej