FairCom DB allows many of its configuration options to include an environment variable name that will be substituted with its value when the configuration file is read. For example, on Windows an administrator might want to set the FairCom DB data directory based on the PROGRAMDATA environment variable:
In this example, %PROGRAMDATA% is replaced with the value of the PROGRAMDATA environment variable (according to the environment variables that are defined in the logon session in which FairCom DB is running).
If you want to specify a literal % sign that is not treated as part of an environment variable name, use %%. For example, if you want to specify a value of ABC%DEF, specify it as ABC%%DEF. A literal % sign cannot be used in an environment variable name; it always signifies the end of the environment variable name. For example, %MY%%VAR% is treated as two environment variables, MY and VAR, rather than one variable named MY%VAR.
The following configuration options support this feature: