onRelativeWorkingDirectory

The R**elative **W**orking **D**irectory, captured in a function **rwd, is the current working directory with the user's HOME stripped from the leading portion of the directory name.

Its become necessary for me to remind myself of this, because a conventional practice is needed. For the moment, it seems that this means an empty argument if in the HOME directory and a leading slash in any sub-directory.

e.g.

$ cd ~/Dropbox
$ rwd            # returns "/Dropbox"

so any use of the rwd function in others relies on this leading slash.