i'm not sure about the RPI-system, but i think you are able to set an alias too
for example on ubuntu, if you want to start the integrated calculator so you need to type gnome-calculator to start the calculator.
if you set an alias, you can start a file/programm with your own command.
alias calculator='gnome-calculator'
now typing calculator starts the gnome-calculator. I'm not sure, but i think this works on RPI too:
alias scummvm=' /opt/retropie/emulators/scummvm/bin/scummvm'