Automatic completion of input file names is turned on by the -e
command-line option (see -e). When this option is in effect, input
file names that
include no period (have no extension) are completed automatically
according to the contents of the following style-file entries:
Type of file Style-file entry Default WEB file ext.webwebChange file ext.chchInclude file ext.hwebhwebChange file for include file ext.hchhch
More than one extension may be specified, as a space-delimited
list--e.g., ext.web = "web wb"; the first one that matches is used.