‘Free’ online packages of the AIX debugging tool, dbx, are hard to find. In fact, I do not believe it is freely available unless someone copies it from their installation medium and places it online. My searches turned up nothing. Eventually, I just installed it from the local install media using “smitty install“.
dbx on AIX is part of the bos.adt.debug (Base Application Development) software bundle. If you have the installation media inserted (usually the first CD/DVD), typically accessible via the device ‘cd0’ you can install dbx by performing the following:
# smitty install