Your 1st code snippet prints 5 for me, as expected. I tried it on 2 versions of perl:

This is perl 5, version 12, subversion 2 (v5.12.2) built for x86_64-li
+nux

This is perl 5, version 14, subversion 2 (v5.14.2) built for x86_64-li
+nux-thread-multi
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Check for unexpected line endings? cat -A