Doc Notes
---------

- Can be run as a freestanding program or loaded into
  current shell context as a callable function.

- -dd is effective immediately upon reading command line so
  you can clean multiple graveyards with:

   /trm.sh -g ./foo -d -g ./baz -d

- Options processed in l-r order.  For example
  Note difference between -vd and -dv-

- Note that symlinks are not expanded but that targets
  accessed via symlinks are stored to canonical path.

- Test mode has no effect on -d which always works

- Note differences between how serial numbers are appended
  on directories vs. files.

- $TRM environment variable