Dump(8) does not do incremental

[Wayne Sierke]

On Thu, 2015-04-02 at 21:51 -0600, Warren Block wrote:
> On Fri, 3 Apr 2015, Olivier Nicole wrote:
> 
> > Thanks Warren,
> >
> >>> Is there any reason why dump would not do incremental when used with -f -?
> >> -u to update /etc/dumpdates after a success?
> >
> > That was it. But I now wonder what was the twisted reason behind that
> > behaviour (that is not documented, man pages mention the various
> > levels, not saying they are not working unless -u); I understand one
> > may want to not implement the incremental dumps, but the default
> > should enable them.
> 
> Hmm.  It should certainly be mentioned in the man page.  I only remember 
> -u because I usually have to look up what it does.

I suppose the man page is not explicit in its explanation of the "Dump
levels" option. Perhaps:

        "tells dump to copy all files new or modified since the last
        dump of any lower level."

could be changed to:

        "tells dump to copy all files new or modified since the last
        dump of any lower level as recorded in dumpdates."
        
or:

"tells dump to copy all files new or modified since the last dump (in
dumpdates) of any lower level."

etc.

(And while we're there perhaps "of any lower level" can become "at any
lower level"?)