The list of directories in which BibDB puts the swapfile when shelling to
DOS, if swapping to disk is indicated. The directories are examined in order
of appearance. If this parameter is missing, the default swap directory
becomes the current directory. The format is similar to that of the DOS PATH
variable, namely directory names, separated by semicolons. The value of an
environment variable may be inserted into the path list by specifying the
variable name, preceded by the `%' character.