$ info sort
‘-k POS1[,POS2]’
‘--key=POS1[,POS2]’
Specify a sort field that consists of the part of the line between
POS1 and POS2 (or the end of the line, if POS2 is omitted),
_inclusive_.In the document do mention if negative filed numbers will ever be added, like perl. Or if users should give up waiting and just use one of the many workarounds.
