See CR 7063702, and blog posts:
http://sim.ivi.co/2011/07/trap-of-case-insensitive-string.html
http://sim.ivi.co/2011/07/simple-shell-script-to-check-trap-of.html
http://sim.ivi.co/2011/07/trap-of-case-insensitive-string.html
http://sim.ivi.co/2011/07/simple-shell-script-to-check-trap-of.html