Defines a catalog variable that will be available in the current catalog with the notation __VARIABLE__. Variable identifiers must begin with a capital letter, and can contain only word characters (A-Z,a-z,0-9 and underscore). They are case-sensitive.
Variable DOCUMENT_ROOT /usr/local/etc/httpd/htdocs
Only variables with ALL CAPS names will be parsed in catalog pages or, when the ParseVariables directive is set, in catalog configuration directives (other than in Variable directives themselves). These are substituted second (right after global Variables) in any Interchange page, and can contain any valid Interchange tags except global variables. If a variable is called with the notation @_VARIABLE_@, and there is no catalog Variable with its name, the global Variable value will be inserted.