On 8/14/23 01:56, Renaud Pacalet wrote:
On 13/08/2023 17:09, Pádraig Brady wrote:
On 13/08/2023 15:40, Renaud Pacalet wrote:
I am a bit surprised that it has never been suggested before but I could
not find any trace of it, so here it is:
Would it be possible to specify the sorting keys from the end of the
record, instead of the beginning. Something like sort -k-1,-1 to sort on
the last field of each record, sort -k-2,-2 for the second to last...
This would be handy when the format has a variable number of fields per
record but the last records are well defined.
I vaguely remember this being suggested before ...
https://lists.gnu.org/archive/html/bug-coreutils/2006-12/msg00008.html
Ah, so it has been suggested before, thanks for the link.
I got about halfway through implementing this in toybox because "eh, why not?"
and hit a design question:
In the existing code, a number off the _right_ edge doesn't count, ala:
$ echo -e 'one\ntwo\nthree\nfour' | sort -sk2
one
two
three
four
$ echo -e 'one\ntwo\nthree\nfour' | sort -sk1
four
one
three
two
So when a negative number is off the _left_ edge, does it get trimmed to field 1
or does it not match? Ala would -k-2 become -k1 or -k9999999 for lines that
don't have two fields?
(I assume the same answer applies to the dot-fields, ala -k-1.-3,-2.-5 and so
on...)