dictionary sort

[kung]

Hi,

I could not sort the following correctly:

address@hidden /tmp]$ more j.tmp
abc NA
ab  NA
address@hidden /tmp]$ sort j.tmp
abc NA
ab  NA

using gnu sort. The right answer should be

ab  NA
abc NA

as in Solaris:

homer% more j.tmp
abc NA
ab  NA
homer% sort j.tmp
ab  NA
abc NA

How can I do?

Thanks.

Dave