The version of sort shipped with RH6.1 sorts in a case-insensitive
manner by default (as though -f was specified). I can't find any
way to disable this behavior, and force a case sensitive sort.
This was actually a feature of textutils 2.0: Sorting by locales.
I've reverted sort to the old behavior in Raw Hide.
Use "sort -l" to get the behavior from 6.1.