Usage: bdftruncate [+w|-w] threshold <source.bdf >destination.bdf
   or: bdftruncate [--help|--version]

Example:

  bdftruncate 0x3200 <6x13.bdf >6x13t.bdf

will generate the file 6x13t.bdf in which all glyphs with codes
>= 0x3200 will only be stored unencoded (i.e., ENCODING -1).
Option -w removes East Asian Wide and East Asian FullWidth characters
(default if threshold <= 0x3200), and option +w keeps them.