`testfiles.$filenum' is specified, file number 4 for any job will be
named `testfiles.4'. The default of `$jobname.$jobnum.$filenum'
will be used if no other format specifier is given.
+.P
+If you specify a path then the directories will be created up to the main
+directory for the file. So for example if you specify `a/b/c/$jobnum` then the
+directories a/b/c will be created before the file setup part of the job. If you
+specify \fBdirectory\fR then the path will be relative that directory, otherwise
+it is treated as the absolute path.
.RE
.TP
.BI unique_filename \fR=\fPbool