diff --git a/t/1.data b/t/1.data
new file mode 100644
index 0000000..3bbc7d5
--- /dev/null
+++ b/t/1.data
@@ -0,0 +1,4 @@
+date val1 val2
+2006-06-01 1 4
+2006-07-01 2 1
+2006-08-01 4 0
diff --git a/t/1.vdata b/t/1.vdata
new file mode 100644
index 0000000..2783f26
--- /dev/null
+++ b/t/1.vdata
@@ -0,0 +1,6 @@
+2006-06-01	val1	1
+2006-06-01	val2	4
+2006-07-01	val1	2
+2006-07-01	val2	1
+2006-08-01	val1	4
+2006-08-01	val2	0
diff --git a/t/2scripts.t b/t/2scripts.t
new file mode 100755
index 0000000..638f61f
--- /dev/null
+++ b/t/2scripts.t
@@ -0,0 +1,24 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use Test::More tests => 7;
+
+my $ps1=`./blib/script/tsplot --output_format ps t/1.data`;
+ok($ps1, 				'Postscript output of tsplot is not empty');
+ok($ps1 =~ m/\(2006-06-04\) Rshow/,	'Postscript output of tsplot contains a date');
+ok($ps1 =~ m/\(val1\) Rshow/,		'Postscript output of tsplot contains a column name');
+
+my $ps2=`./blib/script/tsplotv --output_format ps t/1.vdata`;
+ok($ps2,				'Postscript output of tsplot is not empty');
+ok($ps2 =~ m/\(2006-06-04\) Rshow/,	'Postscript output of tsplot contains a date');
+ok($ps2 =~ m/\(val1\) Rshow/,		'Postscript output of tsplot contains a column name');
+
+# title and creation date will be different, but the rest should be
+# identical:
+$ps1 =~ s/^%%Title: .*//m;
+$ps1 =~ s/^%%CreationDate: .*//m;
+$ps2 =~ s/^%%Title: .*//m;
+$ps2 =~ s/^%%CreationDate: .*//m;
+ok($ps1 eq $ps2, 			'output of tsplot and tsplotv are identical');
+
+#vim:tw=0
diff --git a/tsplot b/tsplot
index b7fe042..0135625 100755
--- a/tsplot
+++ b/tsplot
@@ -1,10 +1,16 @@
 #!/usr/bin/perl -w 
 use strict;
 use TimeSeries;
+use Getopt::Long;
+
+my $output_format ='png';
+GetOptions('output_format|output-format=s' => \$output_format) 
+    or die "Usage: $0 [--output_format format] [files...]\n";
+
 
 binmode STDOUT, ':raw';
 
-my $ts = TimeSeries->new();
+my $ts = TimeSeries->new(output_format => $output_format);
 while (<>) {
     my @legend = split;
     shift @legend;	# first must be for timestamp
diff --git a/tsplotv b/tsplotv
index 80fa693..8964212 100755
--- a/tsplotv
+++ b/tsplotv
@@ -13,6 +13,16 @@ each line contains a tripel <time, series, value>.
 
 use strict;
 use TimeSeries;
+use Getopt::Long;
+
+my $output_format ='png';
+my $stacked = 0;
+my $legend_position = 'top right';
+GetOptions('output_format|output-format=s' => \$output_format,
+	   'stacked' => \$stacked,
+	   'legend_position|legend-position=s' => \$legend_position,
+) or die "Usage: $0 [--output_format format] [files...]\n";
+
 
 binmode STDOUT, ':raw';
 
@@ -20,7 +30,7 @@ my %series;
 my $ns;
 my %data;
 
-my $ts = TimeSeries->new();
+my $ts = TimeSeries->new(output_format => $output_format);
 while (<>) {
     chomp;
     my ($timestamp, $series, $value) = split(/\t/);
@@ -29,8 +39,8 @@ while (<>) {
 }
 my @series = sort { $series{$a} <=> $series{$b} } keys %series;
 $ts->legend(@series);
-$ts->legend_position("below");
-$ts->stacked(1);
+$ts->legend_position($legend_position);
+$ts->stacked($stacked);
 for my $timestamp (sort keys %data) {
     my %d = %{$data{$timestamp}};
     my @values = @d{@series};