HTDBM(1)                                                       htdbm                                                       HTDBM(1)

       htdbm - Manipulate DBM password databases

       htdbm [ -TDBTYPE ] [ -i ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] filename username

       htdbm -b [ -TDBTYPE ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] filename username password

       htdbm -n [ -i ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] username

       htdbm -nb [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] username password

       htdbm -v [ -TDBTYPE ] [ -i ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] filename username

       htdbm -vb [ -TDBTYPE ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] filename username password

       htdbm -x [ -TDBTYPE ] filename username

       htdbm -l [ -TDBTYPE ]

       htdbm is used to manipulate the DBM format files used to store usernames and password for basic authentication of HTTP users
       via mod_authn_dbm. See the dbmmanage documentation for more information about these DBM files.

       -b     Use batch mode; i.e., get the password from the command line rather than prompting for it. This option should be used
              with extreme care, since the password is clearly visible on the command line. For script use see the -i option.

       -i     Read the password from stdin without verification (for script usage).

       -c     Create  the  passwdfile.  If passwdfile already exists, it is rewritten and truncated. This option cannot be combined
              with the -n option.

       -n     Display the results on standard output rather than updating a database. This option changes the syntax of the command
              line, since the passwdfile argument (usually the first one) is omitted. It cannot be combined with the -c option.

       -m     Use MD5 encryption for passwords. On Windows and Netware, this is the default.

       -B     Use bcrypt encryption for passwords. This is currently considered to be very secure.

       -C     This  flag is only allowed in combination with -B (bcrypt encryption). It sets the computing time used for the bcrypt
              algorithm (higher is more secure but slower, default: 5, valid: 4 to 31).

       -d     Use crypt() encryption for passwords. The default on all platforms but Windows and Netware. Though possibly supported
              by htdbm on all platforms, it is not supported by the httpd server on Windows and Netware. This algorithm is insecure
              by today's standards.

       -s     Use SHA encryption for passwords. Facilitates migration from/to Netscape servers using the LDAP Directory Interchange
              Format (ldif). This algorithm is insecure by today's standards.

       -p     Use plaintext passwords. Though htdbm will support creation on all platforms, the httpd daemon will only accept plain
              text passwords on Windows and Netware.

       -l     Print each of the usernames and comments from the database on stdout.

       -v     Verify the username and password. The program will print a message indicating whether the supplied password is valid.
              If the password is invalid, the program exits with error code 3.

       -x     Delete user. If the username exists in the specified DBM file, it will be deleted.

       -t     Interpret  the  final  parameter as a comment. When this option is specified, an additional string can be appended to
              the command line; this string will be stored in the "Comment" field of the database, associated  with  the  specified

              The  filename  of the DBM format file. Usually without the extension .db, .pag, or .dir. If -c is given, the DBM file
              is created if it does not already exist, or updated if it does exist.

              The username to create or update in passwdfile. If username does not exist in this file, an entry  is  added.  If  it
              does exist, the password is changed.

              The plaintext password to be encrypted and stored in the DBM file. Used only with the -b flag.

              Type of DBM file (SDBM, GDBM, DB, or "default").

       One  should  be aware that there are a number of different DBM file formats in existence, and with all likelihood, libraries
       for more than one format may exist on your system. The three primary examples are SDBM, NDBM, GNU GDBM, and Berkeley/Sleepy‐
       cat  DB  2/3/4.  Unfortunately,  all these libraries use different file formats, and you must make sure that the file format
       used by filename is the same format that htdbm expects to see. htdbm currently has no way of determining what  type  of  DBM
       file it is looking at. If used against the wrong format, will simply return nothing, or may create a different DBM file with
       a different name, or at worst, it may corrupt the DBM file if you were attempting to write to it.

       One can usually use the file program supplied with most Unix systems to see what format a DBM file is in.

       htdbm returns a zero status ("true") if the username and password have been successfully added or updated in the  DBM  File.
       htdbm  returns  1 if it encounters some problem accessing files, 2 if there was a syntax problem with the command line, 3 if
       the password was entered interactively and the verification entry didn't match, 4 if its operation was interrupted, 5  if  a
       value  is  too  long (username, filename, password, or final computed record), 6 if the username contains illegal characters
       (see the Restrictions section), and 7 if the file is not a valid DBM password file.

             htdbm /usr/local/etc/apache/.htdbm-users jsmith

       Adds or modifies the password for user jsmith. The user is prompted for the password. If executed on a Windows  system,  the
       password will be encrypted using the modified Apache MD5 algorithm; otherwise, the system's crypt() routine will be used. If
       the file does not exist, htdbm will do nothing except return an error.

             htdbm -c /home/doe/public_html/.htdbm jane

       Creates a new file and stores a record in it for user jane. The user is prompted for the password. If the  file  exists  and
       cannot be read, or cannot be written, it is not altered and htdbm will display a message and return an error status.

             htdbm -mb /usr/web/.htdbm-all jones Pwd4Steve

       Encrypts the password from the command line (Pwd4Steve) using the MD5 algorithm, and stores it in the specified file.

       Web  password  files  such as those managed by htdbm should not be within the Web server's URI space -- that is, they should
       not be fetchable with a browser.

       The use of the -b option is discouraged, since when it is used the unencrypted password appears on the command line.

       When using the crypt() algorithm, note that only the first 8 characters of the password are used to form  the  password.  If
       the supplied password is longer, the extra characters will be silently discarded.

       The  SHA  encryption  format  does  not  use  salting: for a given password, there is only one encrypted representation. The
       crypt() and MD5 formats permute the representation by prepending a random salt string, to make  dictionary  attacks  against
       the passwords more difficult.

       The SHA and crypt() formats are insecure by today's standards.

       On  the  Windows platform, passwords encrypted with htdbm are limited to no more than 255 characters in length. Longer pass‐
       words will be truncated to 255 characters.

       The MD5 algorithm used by htdbm is specific to the Apache software; passwords encrypted using it will  not  be  usable  with
       other Web servers.

       Usernames are limited to 255 bytes and may not include the character :.

Apache HTTP Server                                           2018-07-06                                                    HTDBM(1)