field-separator=SEP  use SEP instead of non-blank to blank transition
  -T, --temporary-directory=DIR  use DIR for temporaries, not $TMPDIR or %s;
                              multiple options specify multiple directories
      --parallel=N          change the number of sorts run concurrently to N
  -u, --unique              with -c, check for strict ordering;
                              without -c, output only the first of an equal run
