o Msort can be used as a command-line program or via a graphical user
interface that is helpful not only to those who find a complicated command
line difficult to deal with but also to those unfamiliar with the finer
points of sorting.
o Records need not be single lines of text but may be delimited in a number
of ways.
o Key fields may be selected by position in the record (counting from the
beginning or the end), by character ranges (e.g. the key consists of the
fourth through eighth characters), or by matching a regular expression to
a tag.
o For each key an arbitrary sort order may be specified. Msort also
understands locales.
o For each key an effectively unlimited number of multigraphs (sequences
of characters to be treated as a single unit for purposes of sorting,
"collating elements" in Unicode parlance) of effectively unlimited length
may be defined.
o In addition to the usual lexicographic and numerical comparisons, msort
supports hybrid lexicographic-numeric comparison (for things like filenames
and section headings, so that, e.g., 2a will precede 10b), random
comparison, and ordering by angle, date, time, month name, domain name,
email address, ISO8601 date-time, and string length.
o Numbers may be in just about any known number system, e.g. Chinese or
Devanagari.
o For each key a distinct set of characters may be excluded from
consideration when sorting in any combination of initial, final, and
medial position in the key field.
o For each key a distinct set of regular expression substitutions may be
defined. These provide the means to make names like McCarthy sort before
MacCawley, as if McCarthy were spelled MacCarthy as well as to handle the
rare cases in which a single character is treated for purposes of sorting
as a sequence, such as German "eszet" sign, which is traditionally sorted
as if it were ss.
o Lexicographic keys may be reversed, allowing the construction of reverse
dictionaries.
o Any or all keys may be optional. For optional keys, the user may specify
how records missing the key field should compare to records in which the
key field is present.
o A choice of sorting algorithms with different properties is provided.
