Confused by restore(8) man page example

[Jerry McAllister]

Subject: Re: Confused by restore(8) man page example

On Mon, Mar 04, 2013 at 10:08:37AM +0000, Steve O'Hara-Smith wrote:

> On Mon, 04 Mar 2013 01:47:24 -0800
> "Ronald F. Guilmette" <rfg at tristatelogic.com> wrote:
> 
> > 
> > In the man page for restore(8) I see the following:
> > 
> >     The -r flag ... can be detrimental to one's health if
> >     not used carefully (not to mention the disk).  An example:
> > 
> >              newfs /dev/da0s1a
> >              mount /dev/da0s1a /mnt
> >              cd /mnt
> > 
> >              restore rf /dev/sa0
> > 
> > Personally, I utterly fail to see what point the author is attempting
> > to illustrate with the above example.  I mean what part of this, exactly,
> > may be "detrimental to one's health" ?  It's an enigma to me.
> 
> 	There's nothing wrong with the example. I think "An example:"
> should be in a new paragraph to make it clear that it is not related to
> the warning. The detrimental effects cut in when you use -r on a filesystem
> that is not pristine, or at least in the expected state for restoring an
> incremental dump.

This and the previous reply are correct.  This example shows
a correct way to use 'restore -r'   

The '-r' flag causes it to write where you are cd-ed to without any
warning what you are doing or overwriting.  If there are other files 
in the directory that is to receive the files from a 'restore -r' has 
other files, you may unexpectedly overwrite some of them.  Also, if 
you are not cd-ed in to the correct place (the mount point, for example)
using the '-r' will quickly write all over whatever directory you
are cd-ed to without warning.    In other words '-r' causes it to
splat out everything right where you are without warning and too fast
to interrupt it before too much damage is done.

I often do a  'restore -r' into an existing -eg not newly newfs-ed, 
directory, but have to make sure I am clear about what I am doing.
For example, I usually keep a large (large for my little stuff) 
drive mounted as '/work'.     Within that filesystem I may create
a directory such as  './unroll'  eg '/work/unroll' or some other
similar name and mass restore a dump in to it using  'restore -r'
so I can easily shuffle files around from the backup in to several 
new directories.  If there are a bunch of destination directories,
it is easier this way than doing a 'restore -i'.   But, as said, I
have to be careful just how I am using it.   It works well.

Have fun,

////jerry    
  
> 
> -- 
> Steve O'Hara-Smith <steve at sohara.org>
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