# HTDBM - Manipulate DBM password databases - man(1) - [phpMan]

[_HTDBM_(1)](https://www.chedong.com/phpMan.php/man/HTDBM/1/markdown)                                        htdbm                                       [_HTDBM_(1)](https://www.chedong.com/phpMan.php/man/HTDBM/1/markdown)

## NAME
       htdbm - Manipulate DBM password databases


## SYNOPSIS
       **htdbm  **[  -**T_**DBTYPE_ ] [ -**i **] [ -**c **] [ -**m **| -**B **| -**d **| -**s **| -**p **] [ -**C _**cost_ ] [ -**t **] [ -**v **] _file‐_
       _name_ _username_


       **htdbm **-**b **[ -**T_**DBTYPE_ ] [ -**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  **[  -**T_**DBTYPE_  ]  [ -**i **] [ -**c **] [ -**m **| -**B **| -**d **| -**s **| -**p **] [ -**C _**cost_ ] [ -**t **] [ -**v **]
       _filename_ _username_


       **htdbm **-**vb **[ -**T_**DBTYPE_ ] [ -**c **] [ -**m **| -**B **| -**d **| -**s **| -**p **] [ -**C _**cost_ ] [ -**t **] [ -**v  **]  _filename_
       _username_ _password_


       **htdbm **-**x **[ -**T_**DBTYPE_ ] _filename_ _username_


       **htdbm **-**l **[ -**T_**DBTYPE_ ]



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



## OPTIONS
### -b     
              it. This option should be used with extreme care, since **the password is clearly  visi‐**
              **ble **on the command line. For script use see the **-i **option.

### -i     

### -c     
              This option cannot be combined with the **-n **option.

### -n     
              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     

### -B     

### -C      -B 
              puting time used for the bcrypt algorithm (higher is more secure but slower,  default:
              5, valid: 4 to 31).

### -d     
              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 stan‐
              dards.

### -s     
              the LDAP Directory Interchange Format (ldif). This algorithm is  **insecure  **by  today's
              standards.

### -p     
              httpd daemon will only accept plain text passwords on Windows and Netware.

### -l     

### -v     
              the supplied password is valid. If the password is invalid, the program exits with er‐
              ror code 3.

### -x     

### -t     
              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.

       _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 encrypted and stored in the DBM file. Used only with  the
              **-b **flag.

### -T_
              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 exe‐
       cuted on a Windows system, the password will be encrypted using the modified Apache MD5 algo‐
       rithm; otherwise, the system's **crypt() **routine will be used. If the file does not exist,  **ht‐**
       **dbm **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 unencrypted password ap‐
       pears 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  en‐
       crypted  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 encrypted with **htdbm **are limited to no more than **255 **char‐
       acters 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                           2018-07-06                                     [_HTDBM_(1)](https://www.chedong.com/phpMan.php/man/HTDBM/1/markdown)