diff --git a/t/2scripts.t b/t/2scripts.t
index 638f61f..ba7f342 100755
--- a/t/2scripts.t
+++ b/t/2scripts.t
@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 use warnings;
 use strict;
-use Test::More tests => 7;
+use Test::More tests => 11;
 
 my $ps1=`./blib/script/tsplot --output_format ps t/1.data`;
 ok($ps1, 				'Postscript output of tsplot is not empty');
@@ -21,4 +21,14 @@ $ps2 =~ s/^%%Title: .*//m;
 $ps2 =~ s/^%%CreationDate: .*//m;
 ok($ps1 eq $ps2, 			'output of tsplot and tsplotv are identical');
 
+my $ps3=`./blib/script/tsplot --output_format ps --log_y t/1.data`;
+ok($ps3,				'Postscript output of tsplot is not empty');
+ok($ps3 !~ m/\( 0\) Rshow/,	'Postscript output of tsplot doesn\'t contain marker "0"');
+ok($ps3 =~ m/\( 1\) Rshow/,	'Postscript output of tsplot contains marker "1"');
+ok($ps3 =~ m/\( 10\) Rshow/,	'Postscript output of tsplot contains marker "10"');
+
+my $fh;
+open($fh, ">", "t/$$.lin.ps"); print $fh $ps1; close($fh);
+open($fh, ">", "t/$$.log.ps"); print $fh $ps3; close($fh);
+
 #vim:tw=0
diff --git a/tsplot b/tsplot
index 0135625..05a2e02 100755
--- a/tsplot
+++ b/tsplot
@@ -3,8 +3,46 @@ use strict;
 use TimeSeries;
 use Getopt::Long;
 
+=head1 NAME
+
+tsplot - plot time series in column format
+
+=head1 SYNOPSIS
+
+tsplotv
+[--legend-position pos]
+[--output-format format ]
+[--stacked]
+[--style style]
+[file ...]
+
+=head1 DESCRIPTION
+
+This program expects time series data in column format, I.e.,
+each line contains a timestamp and the values for each series, except
+the first one which contains the column headers, which are used for the
+legend. Columns are separated by any amount of whitespace.
+
+The default legend position is "top right", same as with gnuplot.
+Another frequently useful position (especially if you have lots of series)
+is "below. Note that positions which consist of several world (such as
+"top right" need to be passed to tsplotv as a single argument, so the 
+space needs to be hidden from the shell by use of quotes or a backslash.
+
+The default output format is "png", the default style is "lines".
+
+See L<TimeSeries> for a description of possible legend positions,
+output formats, and styles.
+
+The --stacked option causes the time series to be stacked on top of each
+other.
+
+=cut
 my $output_format ='png';
-GetOptions('output_format|output-format=s' => \$output_format) 
+my $log_y =0;
+GetOptions('output_format|output-format=s' => \$output_format,
+	   'log_y|log-y'		   => \$log_y,
+          ) 
     or die "Usage: $0 [--output_format format] [files...]\n";
 
 
@@ -21,6 +59,7 @@ while (<>) {
     my ($timestamp, @values) = split();
     $ts->add_timestring($timestamp, @values);
 }
+$ts->log_y($log_y);
 
 my $g = $ts->plot();
 print $g