The problem is that the db2setup script does not properly recognize the architecture x86_64 reported by
uname -m
To make the installation script work, edit the db2setup script and change this:
"Darwin")
case ${OSM?} in
i*86)
INSTALLDIR="${PROGDIR?}/db2/macos/install"
PLATNAME="MacOS" ;;
esac ;;
"HP-UX")
to this:
"Darwin")
case ${OSM?} in
i*86)
INSTALLDIR="${PROGDIR?}/db2/macos/install"
PLATNAME="MacOS" ;;
x86_64)
INSTALLDIR="${PROGDIR?}/db2/macos/install"
PLATNAME="MacOS/x86_64" ;;
esac ;;
"HP-UX")
Now run db2setup. The script should recognize the architecture and proceed with installation as normal.