dbmmanage - Manage user authentication files in DBM format

Synopsis

dbmmanage [ encoding ] filename add|adduser|check|delete|update username [ encpasswd [ group[,group...] [ comment ] ] ]

dbmmanage filename view [ username ]

dbmmanage filename import

Options

filename

The filename of the DBM format file. Usually without the extension .db, .pag, or .dir.

username

The user for which the operations are performed. The username may not contain a colon (:).

encpasswd

This is the already encrypted password to use for the update and add commands. You may use a hyphen (-) if you want to get prompted for the password, but fill in the fields afterwards. Additionally when using the update command, a period (.) keeps the original password untouched.

group

A group, which the user is member of. A groupname may not contain a colon (:). You may use a hyphen (-) if you don't want to assign the user to a group, but fill in the comment field. Additionally when using the update command, a period (.) keeps the original groups untouched.

comment

This is the place for your opaque comments about the user, like realname, mailaddress or such things. The server will ignore this field.

Encodings

-d

crypt encryption (default, except on Win32, Netware)

-m

MD5 encryption (default on Win32, Netware)

-s

SHA1 encryption

-p

plaintext (not recommended)

Commands

add

Adds an entry for username to filename using the encrypted password encpasswd.

adduser

Asks for a password and then adds an entry for username to filename.

check

Asks for a password and then checks if username is in filename and if it's password matches the specified one.

delete

Deletes the username entry from filename.

import

Reads username:password entries (one per line) from STDIN and adds them to filename. The passwords already have to be crypted.

update

Same as the adduser command, except that it makes sure username already exists in filename.

view

Just displays the contents of the DBM file. If you specify a username, it displays the particular record only.

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, the GNU project's GDBM, and Berkeley DB 2. 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 dbmmanage expects to see. dbmmanage 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.

dbmmanage has a list of DBM format preferences, defined by the @AnyDBM::ISA array near the beginning of the program. Since we prefer the Berkeley DB 2 file format, the order in which dbmmanage will look for system libraries is Berkeley DB 2, then NDBM, then GDBM and then SDBM. The first library found will be the library dbmmanage will attempt to use for all DBM file transactions. This ordering is slightly different than the standard @AnyDBM::ISA ordering in Perl, as well as the ordering used by the simple dbmopen() call in Perl, so if you use any other utilities to manage your DBM files, they must also follow this preference ordering. Similar care must be taken if using programs in other languages, like C, to access these files.

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