package: locales version: 2.1.2-10 Given that LC_ALL or LANG triggers this, I'm going to assume it is a locale problem first, though it could be sort itself. Namely, setting the en_US locale forces case-insensitive sorting...
$ sort A b C d A C b d $ LC_ALL=en_US sort A b C d A b C d $ sort --version sort (GNU textutils) 2.0 Written by Mike Haertel. Copyright (C) 1999 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
