I guess lammps doesn’t have those commands. You need to write your own code by cutting the nanowires from a huge box with whatever shape you want and it is not difficult.
You can add region commands pretty easily, but LAMMPS doesn't
have region commands for all the odd shapes you mention. Easiest
is what AC said - generate the geometry you want and put the
atoms in a data file for LAMMPS to read in.