sendmail, 4th Edition

hash

A db(3) form of database V8.1 and later

The hash database map type uses a hashing algorithm for storing data. This approach to a database is described in A New Hash Package for UNIX, by Margo Seltzer (Usenix Proceedings, Winter 1991). The hash type is available only if sendmail was compiled with NEWDB defined and the Berkeley or Sleepycat db(3) library linked.

The hash type is the default that is used with most of the features offered by the mc configuration technique (see Table 23-4 on page 896). For example, consider the following:

Kuudomain hash -o /etc/mail/uudomain

Here, a database map named uudomain is declared to be of type hash. The -o says that the database file /etc/mail/uudomain is optional.

Quite a few other database-map switches are available with this type. The complete list is shown in Table 23-13.

Table 23-13. The hash database-map type K command switches

Switch	§	Description
-A	-A on page 886	Append values for duplicate keys.
-a	-a on page 887	Append tag on successful match.
-D	-D on page 887	Don’t use this database map if DeliveryMode=defer.
-f	-f on page 887	Don’t fold keys to lowercase.
-m	-m on page 888	Suppress replacement on match.
-N	-N on page 889	Append a null byte to all keys.
-O	-O on page 889	Never add a null byte.
-o	-o on page 889	This database map is optional.
-q	-q on page 889	Don’t strip quotes from key.
-S	-S on page 890	Space replacement character.
-T	-T on page 890	Suffix to append on temporary failure.
-t