Msort sorts files in sophisticated ways. Records may be fixed size,
newline-separated blocks, or terminated by any specified character.
Key fields may be selected by position, tag, or character range. For
each key, distinct exclusions, multigraphs, substitutions, and a sort
order may be defined or locale collation rules used. Comparisons may
be lexicographic, numeric, numeric string, hybrid, random, by string
length, angle, date, time, month name, or ISO8601 timestamp. Keys may
be reversed so as to generate reverse dictionaries. Optional keys are
supported. Unicode is supported, including full case-folding. Msort
itself has a somewhat complex command line interface, but may be
driven by an optional GUI.

WWW: http://billposer.org/Software/msort.html