diff --git a/README.md b/README.md
index d419f6d..37f6c64 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,69 @@
 # adif-pota2sig
 
-Convert POTA fields in adif files to SIG and SIG_INFO fields
+Process adif file for POTA uploads
 
-Parse adif file, if a record has one or more POTA_REF entries (delimited by a
-comma), add SIG POTA and SIG_INFO with reference. Multiply record such, that
-every POTA_REF entry is a separate record with own SIG_INFO.
-Extended adif file will be printed to stdout.
+## SYNOPSIS
 
-## Usage:
-```sh
-adif-pota2sig.pl logfile.adi > extended-logfile.adi
-```
+adif-pota2sig.pl -i `in.adi` -o `out.adi`
+
+adif-pota2sig.pl < `in.adi` > `out.adi`
+
+adif-pota2sig.pl -r K-TEST -t `out_REF.adi` -i `in.adi`
+
+adif-pota2sig.pl -r K-TEST -t `out_REF.adi` < `in.adi`
+
+adif-pota2sig.pl -h
+
+## DESCRIPTION
+
+**adif-pota2sig** will read an adif file, if a contact has one or more POTA\_REF
+entries (delimited by a comma), add SIG POTA and SIG\_INFO with reference.
+Multiply contact such, that every POTA\_REF entry is a separate contact with own
+SIG\_INFO. Extendet adif file will be printed to stdout or a file.
+
+If used with **-r** and **-t** options a number of files with contents described
+above will be created. One file for each POTA reference. For output filenames
+see **-t**.
+
+With **-r** you can also include the location in the format REFERENCE@LOCATION,
+which is handy for trails. E. g. -r DE-0622@DE-HH
+
+## OPTIONS
+
+- **-h|--help**
+
+    Print a brief help message and exits.
+
+- **-i `in.adi`|--input=`in.adi`**
+
+    Use `in.adi` as input (default: - for stdin).
+
+- **-o `out.adi`|--output=`out.adi`**
+
+    Use `out.adi` as output (default: - for stdout).
+
+- **-r MY\_POTA\_REF|--reference=MY\_POTA\_REF**
+
+    Use MY\_POTA\_REF as own POTA reference. If there are more than one (for a
+    n-fer) create a list with commas, e. g. **-r** K-TEST1,K-TEST2,K-TEST3.
+
+    Also set the entries MY\_SIG and MY\_SIG\_INFO matching the reference in the
+    output files. By default already existing entries with MY\_SIG and MY\_SIG\_INFO
+    won't be overwritten and the program will stop. Using **-f** will overwrite the
+    entries.
+
+    **-t** is mandatory for this option.
+
+- **-t `out_REF.adi`|--template=`out_REF.adi`**
+
+    Use `out_REF.adi` as output filename template for multiple references. REF
+    will be replaced by a POTA reference. Multiple filenames will be created.
+
+    **-o** is not allowed for this option.
+
+    **-r** is mandatory for this option.
+
+- **-f|--force**
+
+    By default filenames selected with **-o** and **-t** won't be overwritten and the
+    program will stop. Using **-f** will overwrite output files.
diff --git a/adif-pota2sig.pl b/adif-pota2sig.pl
index c27baae..1c00c3d 100755
--- a/adif-pota2sig.pl
+++ b/adif-pota2sig.pl
@@ -8,58 +8,223 @@
 # modified from perlmonks - TedPride - http://www.perlmonks.org/?node_id=559222
 # modified from https://scruss.com/blog/2011/05/23/parsing-adif-with-perl/
 #
-# Description:
-# Parse adif file, if a contact has one or more POTA_REF entries (delimited by
-# a comma), add SIG POTA and SIG_INFO with reference. Multiply contact such,
-# that every POTA_REF entry is a separate contact with own SIG_INFO.
-# Extendet adif file will be printed to stdout.
-#
-# Usage:
-# adif-pota2sig.pl logfile.adi > new-logfile.adi
+# Description and Usage:
+# adif-pota2sig.pl -h
+
+=pod
+
+=head1 NAME
+
+adif-pota2sig - Process adif file for POTA uploads
+
+=head1 SYNOPSIS
+
+adif-pota2sig.pl -i F<in.adi> -o F<out.adi>
+
+adif-pota2sig.pl < F<in.adi> > F<out.adi>
+
+adif-pota2sig.pl -r K-TEST -t F<out_REF.adi> -i F<in.adi>
+
+adif-pota2sig.pl -r K-TEST -t F<out_REF.adi> < F<in.adi>
+
+adif-pota2sig.pl -h
+
+=cut
 
 use strict;
 use warnings;
 
-# use filename.adi as parameter
-open(my $FH, '<', $ARGV[0]) or die "$ARGV[0]: $!";
+use Getopt::Long qw(:config gnu_compat);
+use Pod::Usage;
 
-while (<$FH>) {
-	print;
-	# fast forward past header
-	last if m/<EOH>\s+$/i;
+my $input_file = "";
+my $output_file = "";
+my $my_refs = "";
+my $output_template = "";
+my $force_output = 0;
+
+GetOptions (
+	"i|input=s"	=> \$input_file,
+	"o|output=s"	=> \$output_file,
+	"r|reference=s"	=> \$my_refs,
+	"t|template=s"	=> \$output_template,
+	"f|force"	=> \$force_output,
+	"h|help"	=> sub {pod2usage(-verbose => 2)}
+) or die("Error in command line arguments");
+
+=pod
+
+=head1 DESCRIPTION
+
+B<adif-pota2sig> will read an adif file, if a contact has one or more POTA_REF
+entries (delimited by a comma), add SIG POTA and SIG_INFO with reference.
+Multiply contact such, that every POTA_REF entry is a separate contact with own
+SIG_INFO. Extendet adif file will be printed to stdout or a file.
+
+If used with B<-r> and B<-t> options a number of files with contents described
+above will be created. One file for each POTA reference. For output filenames
+see B<-t>.
+
+With B<-r> you can also include the location in the format REFERENCE@LOCATION,
+which is handy for trails. E. g. -r DE-0622@DE-HH
+
+=head1 OPTIONS
+
+=over
+
+=item B<-h|--help>
+
+Print a brief help message and exits.
+
+=item B<-i F<in.adi>|--input=F<in.adi>>
+
+Use F<in.adi> as input (default: - for stdin).
+
+=item B<-o F<out.adi>|--output=F<out.adi>>
+
+Use F<out.adi> as output (default: - for stdout).
+
+=item B<-r MY_POTA_REF|--reference=MY_POTA_REF>
+
+Use MY_POTA_REF as own POTA reference. If there are more than one (for a
+n-fer) create a list with commas, e. g. S<B<-r> K-TEST1,K-TEST2,K-TEST3>.
+
+Also set the entries MY_SIG and MY_SIG_INFO matching the reference in the
+output files. By default already existing entries with MY_SIG and MY_SIG_INFO
+won't be overwritten and the program will stop. Using B<-f> will overwrite the
+entries.
+
+B<-t> is mandatory for this option.
+
+=item B<-t F<out_REF.adi>|--template=F<out_REF.adi>>
+
+Use F<out_REF.adi> as output filename template for multiple references. REF
+will be replaced by a POTA reference. Multiple filenames will be created.
+
+B<-o> is not allowed for this option.
+
+B<-r> is mandatory for this option.
+
+=item B<-f|--force>
+
+By default filenames selected with B<-o> and B<-t> won't be overwritten and the
+program will stop. Using B<-f> will overwrite output files.
+
+=back
+
+=cut
+
+if (($my_refs ne "") && ($output_template eq "")) {
+	die "-t is mandatory for -r";
 }
 
-my @entry = ();
-my @pota_refs = ();
-while (<$FH>) {
-	push @entry, $_;
-	if (m/<EOR>\s+$/i) {
-		# entry complete
-		if (scalar(@pota_refs) > 0) {
-			# add sig_info to each pota reference
-			foreach my $ref (@pota_refs) {
-				# print all except last
-				print @entry[0 .. $#entry - 1];
-				# insert POTA SIG
-				print "<SIG:4>POTA\n";
-				print "<SIG_INFO:" . length($ref) . ">" . $ref . "\n";
-				# print last
-				print $entry[-1];
-			}
-		} else {
-			# no park reference in this entry
-			print @entry;
-		}
-		# clear entry and pota refs for next entry
-		@entry = ();
-		@pota_refs = ();
-	} elsif (m/^<POTA_REF:/) {
-		# get last element of split >
-		my $val = (split(/>/))[-1];
-		chomp($val);
-		# fill pota_refs with references
-		@pota_refs = split(/,/, $val);
-		chomp @pota_refs;
+if (($output_template ne "") && ($my_refs eq "")) {
+	die "-r is mandatory for -t";
+}
+
+if (($output_template ne "") && ($output_file ne "")) {
+	die "-o is not allowed with -t";
+}
+
+if (($output_template ne "") && ($output_template !~ /REF/)) {
+	die "-t needs REF in output filename template";
+}
+
+my $FH_IN;
+if (($input_file eq "-") || ($input_file eq "")) {
+	$FH_IN = "STDIN";
+} else {
+	open($FH_IN, '<', $input_file) or die "$input_file: $!";
+}
+
+my %filenames_ref = ();
+
+if ($my_refs ne "") {
+	foreach (split(/,/, $my_refs)) {
+		$filenames_ref{$output_template =~ s/REF/$_/r} = $_;
 	}
+} else {
+	$filenames_ref{$output_file} = "";
 }
-close($FH);
+
+foreach my $output_filename (keys %filenames_ref) {
+	seek $FH_IN, 0, 0;
+
+	my $FH_OUT;
+
+	if (($output_filename eq "-") || ($output_filename eq "")) {
+		$FH_OUT = "STDOUT";
+	} else {
+		if ((-e $output_filename) && (! $force_output)) {
+			die "File $output_filename exists. Use --force to overwrite";
+		} else {
+			open($FH_OUT, '>', $output_filename) or die "$output_filename: $!";
+		}
+	}
+
+	# select filehandle for print
+	select($FH_OUT);
+
+	while (<$FH_IN>) {
+		print;
+		# fast forward past header
+		last if m/<EOH>\s+$/i;
+	}
+
+	my @entry = ();
+	my @pota_refs = ();
+	while (<$FH_IN>) {
+		push @entry, $_;
+		if (m/<EOR>\s+$/i) {
+			# entry complete
+
+			# maybe add MY_SIG
+			my $my_ref = $filenames_ref{$output_filename};
+			if ($my_ref ne "") {
+				my $last = pop(@entry);
+				push(@entry, "<MY_SIG:4>POTA\r\n");
+				push(@entry, "<MY_SIG_INFO:" . length($my_ref) . ">" . $my_ref . "\r\n");
+				push(@entry, $last);
+			}
+
+			# print whole entry
+			if (scalar(@pota_refs) > 0) {
+				# maybe print entry multiple times
+				# add sig_info to each pota reference
+				foreach my $ref (@pota_refs) {
+					# print all except last
+					print @entry[0 .. $#entry - 1];
+					# insert POTA SIG
+					print "<SIG:4>POTA\r\n";
+					print "<SIG_INFO:" . length($ref) . ">" . $ref . "\r\n";
+					# print last
+					print $entry[-1];
+				}
+			} else {
+				# no park reference in this entry
+				# print entry only once
+				print @entry;
+			}
+
+			# clear entry and pota refs for next entry
+			@entry = ();
+			@pota_refs = ();
+		} elsif (m/^<POTA_REF:/) {
+			# get last element of split >
+			my $val = (split(/>/))[-1];
+			chomp($val);
+			# fill pota_refs with references
+			@pota_refs = split(/,/, $val);
+			chomp @pota_refs;
+		} elsif (m/^<MY_SIG(_INFO)?:/) {
+			if ($force_output) {
+				# remove MY_SIG and MY_SIG_INFO
+				pop(@entry);
+			} else {
+				die "MY_SIG exists. Overwrite with --force";
+			}
+		}
+	}
+	close($FH_OUT);
+}
+close($FH_IN);