I understand the difference between memcpy and memmove: memmove handles the overlapping of src and dst. I checked the man page for bcopy and it seems to also handle overlapping. So I'm wondering if there is any difference between memmove and bcopy?
bcopy and memmove do exactly the same thing. However, they take arguments in a different order: bcopy(src, dest, n) vs memmove(dest, src, n). So they can't be two names for the same function.
Historically, bcopy is the older of the two; it was present in 3BSD if memory serves. memmove was invented by the C committee in 1988 or so.
New code should use memmove, as it is required by the C standard and therefore more portable than bcopy.