Bug#4335: cat -vET is lossy - there should be a non-lossy version

[Ian Jackson <ian@chiark.chu.cam.ac.uk>]

Package: textutils
Version: 1.17-2

-chiark:~> echo -e 'hi^IthereM-z\011hi' | cat -vET
hi^IthereM-z^Ihi$
-chiark:~>

As you can see, it's not possible to distinguish a single escaped
control character ^<something> or M-<something> from the corresponding
sequence of printable characters.

There should be an option to do a reversible transformation.  I don't
particularly care what the transformation is, provided that it's not
insane.

Ian.