bug#21746: 24.5; purpose of dired-keep-marker-copy?

[Drew Adams]

> I have never figured out a
> reason why copying a file in dired gives the copied file a marker
> `C'.

The reason (IMO) is that the marker indicates what the
operation was, so you can easily identify - *and then
operate on* the files that were copied (or whatever
the operation was).

What might be missing for you is this bit of info:
`* c' lets you change the char that is used for a given
mark.  So you can, for example, change all `C' marks at
a given moment to, say, `*' marks, and then use any
action on the marked files (which acts on `*'-marked
files).  Or change it to `D' and then delete the flagged
files.

Because mark `C' is used, there is no confusion with
files that might be marked with `*' or any other mark.

You can have any number of different marks at any time,
giving them any conceptual meaning you like.  Change
any of them to `*' to convert their files and dirs to
a set that you then act on in some way.

Dunno how much of this is documented in the manual,
but once you look at `C-h m' and then its mention
of `* c', you can pretty much imagine how it can be
put to good use.