Improper behavior in sort utility

[Mark Frost]

Hello,
It appears that sort does not examine the proper fields specified by
'-k' unless the '-n' option is given.

(Behavior observed on 4.5.3 utils included withRedHat EL3.  Behavior
is consistent with compiled 5.0 binaries from gnu.org)

localhost$sort --version
sort (coreutils) 4.5.3
Written by Mike Haertel and Paul Eggert.
....
localhost$ cat sort_challenge6
0 1 0 2 1
0 0 1 2 9
0 0 0 3 5
0 1 1 3 4
1 0 0 1 3
1 1 1 2 6
1 1 1 1 2
1 1 0 4 7
1 0 1 4 8
localhost$ sort -s -k 3 sort_challenge6
1 0 0 1 3
0 1 0 2 1
0 0 0 3 5
1 1 0 4 7
1 1 1 1 2
1 1 1 2 6
0 0 1 2 9
0 1 1 3 4
1 0 1 4 8
>>>>>>>>>This sort appears to sort by all fields following field 3
localhost$ sort -s -n -k 3 sort_challenge6
0 1 0 2 1
0 0 0 3 5
1 0 0 1 3
1 1 0 4 7
0 0 1 2 9
0 1 1 3 4
1 1 1 2 6
1 1 1 1 2
1 0 1 4 8
>>>>>>>>>Adding '-n' fixes the trouble


localhost$ sort -s -k 3 -k 5 sort_challenge6
1 0 0 1 3
0 1 0 2 1
0 0 0 3 5
1 1 0 4 7
1 1 1 1 2
1 1 1 2 6
0 0 1 2 9
0 1 1 3 4
1 0 1 4 8
>>>>>>>>>The second key argument is ignored and results are identical
to 'sort -s -k 3 sort_challenge6' above
localhost$ sort -n -s -k 3 -k 5 sort_challenge6
0 1 0 2 1
1 0 0 1 3
0 0 0 3 5
1 1 0 4 7
1 1 1 1 2
0 1 1 3 4
1 1 1 2 6
1 0 1 4 8
0 0 1 2 9
>>>>>>>>>Adding the '-n' corrects this as well.

Mark Frost
--
"When trouble arises and things look bad, there is always one
individual who perceives a solution and is willing to take command. 
Very Often, that individual is crazy."
--Dave Barry