\Trace/BPT trap: 5 when using open from terminal
there.  I had this problem and so I cleared out some old launchd plists, some of which dated back to Leopard (I restore via Time Machine when I get a new Mac.)  So far, that seems to have worked.  If you check out "man launchd" and scroll to the bottom, there's a list of folders where such files may be found.  Leave anything by Apple, and clear out the questionable ones.  I no longer have any Adobe software on my Mac, ditto for MS Office, and I'm trying ClamAV instead of Avast, so I cleared out all the Adobe, Microsoft, and Avast plists.  Haven't even rebooted yet and suddenly I can use "open" reliably again.