Carletto, could you, or anyone really, tell what the world is HJSPLIT? I can't even tell you how computer illiterate I am.
it joins all the .001, .002, .... , .00x files.
so if you're downloading filename.avi.001, filename.avi.002 and filename.avi.003, hjsplit joins it into filename.avi
also you can create .00x files with hjsplit. Kind of like rar except only for single files, not directories. But it is faster in creating and extracting than rar so that's an advantage.