coreutils: Charset selection in ptx

 
 7.5.2 Charset selection
 -----------------------
 
 As it is set up now, ‘ptx’ assumes that the input file is coded using
 8-bit characters, and it may not work well in multibyte locales.  In a
 single-byte locale, the default regular expression for a keyword allows
 foreign or diacriticized letters.  Keyword sorting, however, is still
 crude; it obeys the underlying character set ordering quite blindly.
 
    The output of ‘ptx’ assumes the locale’s character encoding.  For
 example, with ‘ptx’’s ‘-T’ option, if the locale uses the Latin-1
 encoding you may need a LaTeX directive like
 ‘\usepackage[latin1]{inputenc}’ to render non-ASCII characters
 correctly.
 
 ‘-f’
 ‘--ignore-case’
      Fold lower case letters to upper case for sorting.