The following
main.cf configuration parameters are exported as environment variables with the same names:command_directory (see 'postconf -d' output)
The location of all postfix administrative commands.
daemon_directory (see 'postconf -d' output)
The directory with Postfix support programs and daemon programs.
config_directory (see 'postconf -d' output)
The default location of the Postfix main.cf and master.cf configuration files.
queue_directory (see 'postconf -d' output)
The location of the Postfix top-level queue directory.
mail_owner (postfix)
The UNIX system account that owns the Postfix queue and most Postfix daemon processes.
setgid_group (postdrop)
The group ownership of set-gid Postfix commands and of group-writable Postfix directories.
sendmail_path (see 'postconf -d' output)
A Sendmail compatibility feature that specifies the location of the Postfix sendmail(1) command.
newaliases_path (see 'postconf -d' output)
Sendmail compatibility feature that specifies the location of the newaliases(1) command.
mailq_path (see 'postconf -d' output)
Sendmail compatibility feature that specifies where the Postfix mailq(1) command is installed.
html_directory (see 'postconf -d' output)
The location of Postfix HTML files that describe how to build, configure or operate a specific Postfix subsystem or feature.
manpage_directory (see 'postconf -d' output)
Where the Postfix manual pages are installed.
readme_directory (see 'postconf -d' output)
The location of Postfix README files that describe how to build, configure or operate a specific Postfix subsystem or feature.
Available in Postfix version 2.5 and later:
data_directory (see 'postconf -d' output)
The directory with Postfix-writable data files (for example: caches, pseudo-random numbers).
Other configuration parameters:
config_directory (see 'postconf -d' output)
The default location of the Postfix main.cf and master.cf configuration files.
import_environment (see 'postconf -d' output)
The list of environment parameters that a Postfix process will import from a non-Postfix parent process.
syslog_facility (mail)
The syslog facility of Postfix logging.
syslog_name (see 'postconf -d' output)
The mail system name that is prepended to the process name in syslog records, so that "smtpd" becomes, for example, "postfix/smtpd".
Available in Postfix version 2.6 and later:
multi_instance_directories (empty)
An optional list of non-default Postfix configuration directories; these directories belong to additional Postfix instances that share the Postfix executable files and documentation with the default Postfix instance, and that are started, stopped, etc., together with the default Postfix instance.
multi_instance_wrapper (empty)
The pathname of a multi-instance manager command that the postfix(1) command invokes when the multi_instance_directories parameter value is non-empty.
multi_instance_group (empty)
The optional instance group name of this Postfix instance.
multi_instance_name (empty)
The optional instance name of this Postfix instance.
multi_instance_enable (no)
Allow this Postfix instance to be started, stopped, etc., by a multi-instance manager.