# pwconv

## NAME



           pwconv, pwunconv, grpconv, grpunconv - convert between the
           system's shadowed and plain account files
    


## SYNOPSIS



    
           **pwconv**[_options_]
    
           **pwunconv**[_options_]
    
           **grpconv**[_options_]
    
           **grpunconv**[_options_]
    


## DESCRIPTION



           The **pwconv** command creates shadow from passwd and an optionally
           existing shadow.
    
           The **pwunconv** command creates a plain passwd from shadowed passwd
           and shadow and then removes shadow.
    
           The **grpconv** command creates gshadow from group and an optionally
           existing gshadow.
    
           The **grpunconv** command creates plain group from shadowed group and
           gshadow and then removes gshadow.
    
           These four programs all operate on the normal and shadow password
           and group files: /etc/passwd, /etc/group, /etc/shadow, and
           /etc/gshadow.
    
           Each program acquires the necessary locks before conversion.
           **pwconv** and **grpconv** are similar. First, entries in the shadowed
           file which don't exist in the plain file are removed. Then,
           entries in the shadowed file which don't have `x' as the password
           in plain file are updated. Any missing shadowed entries are added.
           Finally, passwords in the plain file are replaced with `x'. These
           programs can be used for initial conversion as well to update the
           shadowed file if the plain file has been 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 similar. Passwords in the
           plain file are updated from the shadowed file. Entries which exist
           in the plain file but not in the shadowed file are left alone.
           Finally, the shadowed file is removed. Some password aging
           information is lost by **pwunconv**. It will convert what it can.
    


## OPTIONS



           The options which apply to the **pwconv** , **pwunconv** , **grpconv** , and
           **grpunconv** commands are:
    
           **-h** , **--help**
               Display help message and exit.
    
           **-R** , **--root** _CHROOT_DIR_
               Apply changes in the _CHROOT_DIR_ directory and use the
               configuration files from the _CHROOT_DIR_ directory. Only
               absolute paths are supported.
    


## BUGS



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


## CONFIGURATION



           The following configuration variable in /etc/login.defs changes
           the behavior of **grpconv** and **grpunconv** :
    
           **MAX_MEMBERS_PER_GROUP**(number)
               Maximum members per group entry. When the maximum is reached,
               a new group entry (line) is started in /etc/group (with the
               same name, same password, and same GID).
    
               The default value is 0, meaning that there are no limits in
               the number of members in a group.
    
               This feature (split group) permits to limit the length of
               lines in the group file. This is useful to make sure that
               lines for NIS groups are not larger than 1024 characters.
    
               If you need to enforce such limit, you can use 25.
    
               Note: split groups may not be supported by all tools (even in
               the Shadow toolsuite). You should not use this variable unless
               you really need it.
    
           The following configuration variables in /etc/login.defs change
           the behavior of **pwconv** :
    
           **PASS_MAX_DAYS**(number)
               The maximum number of days a password may be used. If the
               password is older than this, a password change will be forced.
               If not specified, -1 will be assumed (which disables the
               restriction).
    
           **PASS_MIN_DAYS**(number)
               The minimum number of days allowed between password changes.
               Any password changes attempted sooner than this will be
               rejected. If not specified, 0 will be assumed (which disables
               the restriction).
    
           **PASS_WARN_AGE**(number)
               The number of days warning given before a password expires. A
               zero means warning is given only upon the day of expiration, a
               value of -1 means no warning is given. If not specified, no
               warning will be provided.
    


## FILES



           /etc/login.defs
               Shadow password suite configuration.
    


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