the paramters \-B and \-E can be used to execute
.IR code
(see \-r) before and
-after all input lines have been processed respectively.
+after all input lines have been processed respectively. Notice that the
+input is read from
+.B STDIN
+and therefore reading from
+.B STDIN
+explicitly changes the next input line or skips input lines.
.LP
If none of \-r \-f \-B \-R \-F or \-E is present but a single parameter is given
then this parameter is taken as the filename to parse and execute (same as