Running

  bufrread.pl sn.0113.bin --ahl "^IOB" --outfile iob.txt
  
will decode all BUFR BUOY messages from the file sn.0113.bin of GTS bulletins into [[bufrread.pl_iobdat|iob.txt]].

The file sn.0113.bin will be used also at [[start#bufrextract.pl]] providing more examples of how to use the %%--%%ahl option.