bug#14383: cp --one-file-system / will not copy whole root filesystem

[Pádraig Brady]

On 05/10/2013 11:55 AM, Pavel Machek wrote:
> Hi!
> 
> On systems like linux, cp / -a --one-file-system (destination) will
> not copy whole root filesystem. It is not cp's fault, but the
> behaviour is quite surprising to the users, so maybe it would be worth
> warning in man page?
> 
> Something like
> 
>        -x, --one-file-system
>               stay on this file system
> 
>             Note that on systems that allow mounts over non-empty
>             directories (like Linux), cp / -ax (destination) will
>             not copy whole filesystem. In particular, content of
>             /dev will not be usually copied, because distributions
>             mount tmpfs over /dev.
> 
> [Ok, there's hopefully better wording...?]

Well this issue is not restricted to -x of course,
but I suppose it's might be a good place to put a warning.
I suppose you could give the advice to ensure that all
mounts in a tree should be unmounted to ensure that
the base file system contents are copied.
That info would be more appropriate in the texinfo manual,
than the man page I would think.

thanks,
Pádraig.