About other predefined substitution variables
In addition to 
$instanceId (see 
About drilldown and $instanceId), Dashboard Builder defines the following substitution variables:
 $apama_lang
$apama_lang: by default, this variable is set to what Java reports as the locale in the 
Locale object as derived from the host system's locale. You can allow end users to set this to their required locale, and use it to localize dashboard labels. See 
Localizing dashboard labels.
 $apama_roles
$apama_roles: 
Principles: returned by the login module.
 $apama_server_host
$apama_server_host: hostname of the machine running the Data Server or Display Server; empty for Builder and Viewer with a direct connection to a Correlator.
 $apama_server_port
$apama_server_port: port used by the Data Server or Display Server on the host machine; empty for Builder and Viewer with a direct connection to a Correlator.
 $apama_timestamp
$apama_timestamp: by default, this variable is set to the value of 
apama.timestamp of the scenario instance that is currently selected. See 
About timestamps.
 $apama_user
$apama_user: current user, set at login.
 $celldata
$celldata: by default, this variable is set to the value of the cell that is currently selected.
 $colName
$colName: by default, this variable is set to the name of the column of the currently-selected cell.