--- loncom/cgi/plot.gif	2004/06/21 20:04:29	1.11
+++ loncom/cgi/plot.gif	2006/09/06 19:26:07	1.12
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 #
-# $Id: plot.gif,v 1.11 2004/06/21 20:04:29 matthew Exp $
+# $Id: plot.gif,v 1.12 2006/09/06 19:26:07 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -37,12 +37,15 @@ foreach (split/&/,$ENV{'QUERY_STRING'})
 my $filename = $data{'file'};
 # unescape filename
 $filename =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
-
 die if ($filename =~ /\// || $filename !~ /_plot.data$/);
 $filename = $tmpdir . $filename;
 die "$data{'file'} does not exist\n" if (! -e $filename);
 
 my $output = $data{'output'};
+if ($output eq '') {
+    $output = (split('\.',$0))[-1];
+}
+
 if ($output eq 'gif' || $output eq 'png') {
     open PLOT, "gnuplot $filename |";
     print <<"END";