strange 'sort' action

[Ken McDonell]

In article <1155 at Terra.cc.brunel.ac.uk> linda at cc.brunel.ac.uk (Linda Birmingham) writes:
> Has anyone noticed a diference in operation in the 'sort' command
> from OSx4.0 to 4.4 ?
>
> We had a user application that used to work with 'sort' in 4.0
> and doesn't in 4.4.

I cannot explain this, although the example given seems to behave as
expected.

> When we restrict sorting to a particular field it still insists on sorting
> on the first field afterwards.
>
> Try    sort +1 -1.4 try
>
> where try is:
> wwww 0020 ctre ge
> zzzz 0080 btre ge
> vvvv 0110 gtre ge
> yyyy 0090 dtre ge
> tttt 0020 atre ge
> ssss 0040 ftre ge
>
> and notice that the tttt line is placed before the wwww line.
>
> Any comments anyone ??

This will sort on the first four characters of the second field.
sort(1) uses base zero numbering for fields and field-offsets.

to sort of the first field, you need

    ssss 0040 ftre ge
    ^  ^
    |  |
    0  0.3 (but want to finish just before 0.4, so -0.4 or -1)

i.e. sort +0 -0.4 (or sort +0 -1) which both produce

ssss 0040 ftre ge
tttt 0020 atre ge
vvvv 0110 gtre ge
wwww 0020 ctre ge
yyyy 0090 dtre ge
zzzz 0080 btre ge

the original sort +1 -1.4 produces

tttt 0020 atre ge
wwww 0020 ctre ge
ssss 0040 ftre ge
zzzz 0080 btre ge
yyyy 0090 dtre ge
vvvv 0110 gtre ge

note the second field is sorted into lexicographic order.

while I am in tutor mode, be careful of numeric fields as well.  if the
leading zeroes are stripped from the second field, then sort +1 -2 produces

vvvv 110 gtre ge
tttt 20 atre ge
wwww 20 ctre ge
ssss 40 ftre ge
zzzz 80 btre ge
yyyy 90 dtre ge

to sort on the numeric value of the second field requires sort +1n -2

tttt 20 atre ge
wwww 20 ctre ge
ssss 40 ftre ge
zzzz 80 btre ge
yyyy 90 dtre ge
vvvv 110 gtre ge