The contents of other files may be included in the configuration file.
If a line is encountered with a less than sign, <, in
column one, then the rest of the line is treated as a file name; the
file name should always be a full file path. The file is opened and its
contents are spliced into the configuration file at that point. Include
files may be nested up to three levels deep.
Note:
Any files included in the configuration file must be world readable just as the configuration file is world readable.