I would like to open multiple instances of the same file with some sort of command. I've tried some very unsophisticated ideas (e.g., an alias or function in my .bashrc, a simple shell script), but they all open the file once, then open another instance after i close the first open file).

I know it's not a big deal to simply type an aliased command four (say) times, but it must be dead easy to write a command that would call, e.g.,

mupdf /path/to/file/file.pdf

four times so the file is opened four times all at once..?