Turn tracing on or off. Inverts the appropriate bit in C<$trace> (q.v.).
If level is specified, set C<$trace_to_depth>.
-=cut
-
=head4 C<S> - list subroutines matching/not matching a pattern
Walks through C<%sub>, checking to see whether or not to print the name.
-=cut
-
=head4 C<X> - list variables in current package
Since the C<V> command actually processes this, just change this to the
Uses C<dumpvar.pl> to dump out the current values for selected variables.
-=cut
-
=head4 C<x> - evaluate and print an expression
Hands the expression off to C<DB::eval>, setting it up to print the value
via C<dumpvar.pl> instead of just printing it directly.
-=cut
-
=head4 C<m> - print methods
Just uses C<DB::methods> to determine what methods are available.
-=cut
-
=head4 C<f> - switch files
-=cut
+Switch to a different filename.
=head4 C<.> - return to last-executed line.
We set C<$incr> to -1 to indicate that the debugger shouldn't move ahead,
and then we look up the line in the magical C<%dbline> hash.
-=cut
-
=head4 C<-> - back one window
We change C<$start> to be one window back; if we go back past the first line,