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       These four programs all operate on the normal  and  shadow
       password   and   group   files:  /etc/passwd,  /etc/group,
       /etc/shadow, and /etc/gshadow.

       pwconv creates shadow from passwd and an optionally exist­
       ing  shadow.   pwunconv  creates  passwd  from  passwd and
       shadow and then removes shadow.  grpconv  creates  gshadow
       from  group and an optionally existing gshadow.  grpunconv
       creates group from group  and  gshadow  and  then  removes

       Each  program  acquires the necessary locks before conver­

       pwconv and grpconv are similiar.  First,  entries  in  the
       shadowed  file  which  don't  exist  in  the main file are
       removed.  Then, shadowed entries which don't have  `x'  as
       the  password  in  the main file are updated.  Any missing
       shadowed entries are added.   Finally,  passwords  in  the
       main  file  are  replaced with `x'.  These programs can be
       used for initial conversion as well to update the shadowed
       file if the main file is edited by hand.

       pwconv    will    use   the   values   of   PASS_MIN_DAYS,
       PASS_MAX_DAYS, and PASS_WARN_AGE from /etc/login.defs when
       adding new entries to /etc/shadow.

       Likewise,  pwunconv and grpunconv are similiar.  Passwords
       in the main file  are  updated  from  the  shadowed  file.
       Entries  which exist in the main file but not in the shad­
       owed file are left alone.  Finally, the shadowed  file  is

       Some  password  aging information is lost by pwunconv.  It
       will convert what it can.


       Errors in the password or group files (such as invalid  or
       duplicate  entries)  may cause these programs to loop for­
       ever or fail in other strange ways.  Please run  pwck  and
       grpck  to  correct any such errors before converting to or
       from shadow passwords or groups.


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