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 7505094..1c00c3d 100755
--- a/adif-pota2sig.pl
+++ b/adif-pota2sig.pl
@@ -19,13 +19,13 @@ adif-pota2sig - Process adif file for POTA uploads
 
 =head1 SYNOPSIS
 
-adif-pota2sig.pl -i in.adi -o out.adi
+adif-pota2sig.pl -i F<in.adi> -o F<out.adi>
 
-adif-pota2sig.pl < in.adi > out.adi
+adif-pota2sig.pl < F<in.adi> > F<out.adi>
 
-adif-pota2sig.pl -r K-TEST -t out_REF.adi -i in.adi
+adif-pota2sig.pl -r K-TEST -t F<out_REF.adi> -i F<in.adi>
 
-adif-pota2sig.pl -r K-TEST -t out_REF.adi < in.adi
+adif-pota2sig.pl -r K-TEST -t F<out_REF.adi> < F<in.adi>
 
 adif-pota2sig.pl -h
 
@@ -54,6 +54,20 @@ GetOptions (
 
 =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
@@ -73,14 +87,19 @@ 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>
+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 out_REF.adi as output filename template for multiple references. REF will
-be replaced by a POTA reference. Multiple filenames will be created.
+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.
 
@@ -209,18 +228,3 @@ foreach my $output_filename (keys %filenames_ref) {
 	close($FH_OUT);
 }
 close($FH_IN);
-
-__END__
-
-=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. On file for each POTA reference. For output filenames
-see B<-t>.
-
-=cut