I needed to associate phone prefix numbers with their cities and
make it searchable.
You can associate what ever you like. Just create a textfile
with the format:
a,b,c;
d,e,f,g,h;
and so on.
If you skip using the argument "-f filename" on the command line
then Riktnummer will use "s:riktnummer.dat" as the default database.
I've included the swedish phone prefixes/cities database file.
Please feel free to update it! Just remember to upload the altered 
version to the Aminet so others will be able to take advantage of 
it.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                 5533    9336  59.3% -lh5- 9343 May 19  2001 riktnummer
[generic]                 2515    4791  52.5% -lh5- cee0 Apr 27  2001 riktnummer.dat
[generic]                  427     754  56.6% -lh5- fb2d May 19  2001 rn.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         3 files    8475   14881  57.0%            May 19  2001