$ xterm
dld: xterm can't open library: /usr/X11R6/lib/libexpat.1.dylib (No such file or directory, errno = 2)
Trace/BPT trap
$ ls /usr/X11R6/lib/libexpat*
/usr/X11R6/lib/libexpat.0.4.dylib /usr/X11R6/lib/libexpat.dylib
/usr/X11R6/lib/libexpat.0.dylib