When I try to run startserver.sh I get an error message saying Error: Invalid or corrupt jarfile serverstarter-2.1.1.jar
This only happens on macOS, in ubuntu server it works fine.

just remove the DO_RAMDISK=0: from the script

DO_RAMDISK=0: doesn't exist in the script, but when I downloaded a more recent version of the script it just worked, thanks for trying to help!