paths must be a sorted ASCII file that contains entries which map destination site names to UUCP bang paths. The file has to be sorted because smail uses a binary search for looking up a site. Comments are not allowed in this file, and the site name must be separated from the path using a TAB. Pathalias databases are discussed in somewhat greater detail in chapter-.
If you generate this file by hand, you should make sure to include all legal names for a site. For example, if a site is known by both a plain UUCP name and a fully qualified domain name, you have to add an entry for each of them. The file can be sorted by piping it through the sort(1) command.
If your site is only a leaf site, however, then no paths file should be necessary at all: just set up the smart host attributes in your config file, and leave all routing to your mail feed.