htdbm - Manipulate DBM password databases - Apache HTTP Server Version 2.4








Modules | Directives | FAQ | Glossary | Sitemap
Apache HTTP Server Version 2.4



Apache > HTTP Server > Documentation > Version 2.4 > Programshtdbm - Manipulate DBM password databases

Available Languages:  en  |
 fr  |
 tr 


    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.

 Synopsis
 Options
 Bugs
 Exit Status
 Examples
 Security Considerations
 Restrictions
See alsohttpddbmmanagemod_authn_dbmComments


Synopsis
    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 ]
    


Options
    
    -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 hashing for passwords. On Windows and Netware, this is
    the default.

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

    -C
    This flag is only allowed in combination with -B (bcrypt
    hashing). 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() hashing 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 hashing 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 username.

    filename
    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.

    username
    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.

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

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


Bugs
    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/Sleepycat 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.


Exit Status
    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.


Examples
    
      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 hashed 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.


Security Considerations
    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 plaintext 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 hashing option does not use salting: for a given password,
    there is only one hashed 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.


Restrictions
    On the Windows platform, passwords hashed with
    htdbm are limited to no more than 255
    characters in length. Longer passwords will be truncated to 255
    characters.

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

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


Available Languages:  en  |
 fr  |
 tr 

Copyright 2026 The Apache Software Foundation.Licensed under the Apache License, Version 2.0.
Modules | Directives | FAQ | Glossary | Sitemap