If the result files do not exist they will be created with the same group and other read permissions as the source file.

While a database update is in progress, signal delivery is postponed, and an exclusive, advisory, lock is placed on the entire database, in order to avoid surprises in spectator programs.

The format of Postfix alias input files is described in aliases(5).

By default the lookup key is mapped to lowercase to make the lookups case insensitive; as of Postfix 2.3 this case folding happens only with tables whose lookup keys are fixed-case strings such as btree:, dbm: or hash:. With earlier versions, the lookup key is folded even with tables where a lookup field can match both upper and lower case text, such as regexp: and pcre:. This resulted in loss of information with $number substitutions.

Options:

-c config_dir

Read the main.cf configuration file in the named directory instead of the default configuration directory.

-d key

Search the specified maps for key and remove one entry per map. The exit status is zero when the requested information was found.

If a key value of - is specified, the program reads key values from the standard input stream. The exit status is zero when at least one of the requested keys was found.

-f

Do not fold the lookup key to lower case while creating or querying a table.

-i

Incremental mode. Read entries from standard input and do not truncate an existing database. By default, postalias(1) creates a new database from the entries in file_name.

-N

Include the terminating null character that terminates lookup keys and values. By default, postalias(1) does whatever is the default for the host operating system.

-n

Don't include the terminating null character that terminates lookup keys and values. By default, postalias(1) does whatever is the default for the host operating system.

-o

Do not release root privileges when processing a non-root input file. By default, postalias(1) drops root privileges and runs as the source file owner instead.

-p

Do not inherit the file access permissions from the input file when creating a new file. Instead, create a new file with default access permissions (mode 0644).

-q key

Search the specified maps for key and write the first value found to the standard output stream. The exit status is zero when the requested information was found.

If a key value of - is specified, the program reads key values from the standard input stream and writes one line of key: value output for each key that was found. The exit status is zero when at least one of the requested keys was found.

-r

When updating a table, do not complain about attempts to update existing entries, and make those updates anyway.

-s

Retrieve all database elements, and write one line of key: value output for each element. The elements are printed in database order, which is not necessarily the same as the original input order. This feature is available in Postfix version 2.2 and later, and is not available for all database types.

-v

Enable verbose logging for debugging purposes. Multiple -v options make the software increasingly verbose.

-w

When updating a table, do not complain about attempts to update existing entries, and ignore those attempts.

Arguments:

file_type

The database type. To find out what types are supported, use the "postconf -m" command.

The postalias(1) command can query any supported file type, but it can create only the following file types:

btree

The output is a btree file, named file_name.db. This is available on systems with support for db databases.

cdb

The output is one file named file_name.cdb. This is available on systems with support for cdb databases.

dbm

The output consists of two files, named file_name.pag and file_name.dir. This is available on systems with support for dbm databases.

hash

The output is a hashed file, named file_name.db. This is available on systems with support for db databases.

sdbm

The output consists of two files, named file_name.pag and file_name.dir. This is available on systems with support for sdbm databases.

When no file_type is specified, the software uses the database type specified via the default_database_type configuration parameter. The default value for this parameter depends on the host environment.

file_name

The name of the alias database source file when creating a database.

postalias(1) terminates with zero exit status in case of success (including successful "postalias -q" lookup) and terminates with non-zero exit status in case of failure.

MAIL_CONFIG

Directory with Postfix configuration files.

MAIL_VERBOSE

Enable verbose logging for debugging purposes.

The text below provides only a parameter summary. See (5) for more details including examples.

alias_database (see 'postconf -d' output)

The alias databases for (8) delivery that are updated with "newaliases" or with "sendmail -bi".

config_directory (see 'postconf -d' output)

The default location of the Postfix main.cf and master.cf configuration files.

berkeley_db_create_buffer_size (16777216)

The per-table I/O buffer size for programs that create Berkeley DB hash or btree tables.

berkeley_db_read_buffer_size (131072)

The per-table I/O buffer size for programs that read Berkeley DB hash or btree tables.

default_database_type (see 'postconf -d' output)

The default database type for use in newaliases(1), postalias(1) and postmap(1) commands.

syslog_facility (mail)

The syslog facility of Postfix logging.

syslog_name (postfix)

The mail system name that is prepended to the process name in syslog records, so that "smtpd" becomes, for example, "postfix/smtpd".

RFC 822 (ARPA Internet Text Messages)