htdigest - manage user files for digest authentication
    htdigest is used to create and update the flat-files used
    to store usernames, realm and password for digest authentication of HTTP
    users. Resources available from the Apache HTTP server can be restricted
    to just the users listed in the files created by htdigest.
    This manual page only lists the command line arguments. For details of
    the directives necessary to configure digest authentication in
    httpd see the Apache manual, which is part
    of the Apache distribution or can be found at
    http://httpd.apache.org/.
    htdigest [ -c ]
    passwdfile realm username
 
    
    - -c
- Create the passwdfile. If passwdfile already
    exists, it is deleted first.
- passwdfile
- Name of the file to contain the username, realm and password. If
    -cis given, this file is created if it does not already
    exist, or deleted and recreated if it does exist.
- realm
- The realm name to which the user name belongs.
- username
- The user name to create or update in passwdfile. If
    username does not exist is this file, an entry is added. If it
    does exist, the password is changed.