Global directives are configuration options that apply to the rsyslogd daemon. They usually specify a value for a specific predefined variable that affects the behavior of the rsyslogd daemon or a rule that follows. All of the global directives must start with a dollar sign ($). Only one directive can be specified per line. The following is an example of a global directive that specifies the maximum size of the syslog message queue:

$MainMsgQueueSize 50000

The default size defined for this directive (10,000 messages) can be overridden by specifying a different value (as shown in the example above).

You can define multiple directives in your /etc/rsyslog.conf configuration file. A directive affects the behavior of all configuration options until another occurrence of that same directive is detected. Global directives can be used to configure actions, queues and for debugging. A comprehensive list of all available configuration directives can be found in the section called “Online Documentation”. Currently, a new configuration format has been developed that replaces the $-based syntax (see Section 25.4, “Using the New Configuration Format”). However, classic global directives remain supported as a legacy format.