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CentOS 7.0 - man page for htdbm (centos section 1)

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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  ]  file-
       name 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

       -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

       -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 addi-
	      tional 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.

	      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/Sleepycat DB 2/3/4. Unfortu-
       nately, 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 dif-
       ferent name, or at worst, it may corrupt the DBM file if you were attempting to	write  to

       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

       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 passwords 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			    2012-12-12					 HTDBM(1)
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