David's response is correct, but it doesn't answer the original question.
The reason for passwd- and shadow- are to keep a backup of the previous
passwd and shadow files. If you add a new user to the system using
useradd, for example, then your current passwd file will be moved to
passwd-. If you somehow hose your passwd file, then you could always
recover the most recent version by moving passwd- to passwd.
~M
On 21 Feb 2002, David Mandala wrote:
> The reason for the shadow file is /etc/passwd is world readable and
> needs to be, however if someone can gain access to the actual hashed
> passwords that at one time were contained in the passwd file you can do
> a brute force attack and gain access to different accounts on the
> machine. By moving the actual hassed passwords out of the passwd file
> into the root only readable shadow file it is much harder for someone to
> capture the actual password hashes and without those it is MUCH harder
> to attempt a brute force attack on a machine.
>
> On Thu, 2002-02-21 at 15:10, JM wrote:
> > What is the purpose for the file /etc/shadow-
> > or for the files
> > /etc/passwd-
> > /etc/gshadow-
> > /etc/group-
> >
> > These files are nearly identical to their
> > cognates in content and file attributes.
> > Is there a simple explanation for maintaining
> > these files along with the standard file:
> >
> > /etc/shadow, /etc/passwd, /etc/gshadow, /etc/group ?
> >
> > Is the a common convention for other Unix-like systems?
> >
> > My reason for asking is that this is a minor inconvenience
> > when hiding this /etc/shadow- file and what programs may
> > be using this file.
> >
> > Jerry M.
> > a RedHat user
> >
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