The part in parens produces an anonymous array that the "for" will iterate over, and the last element of that array the "undef" element from the last attempt to read from the file handle and encountering 'eof'. If you used a while loop instead, you wouldn't enter the block (lines 25 and 26 would not be reached) on that last attempt to read from the file.

um, none of that :) if the match fails $participant is undef , when you try to print var which is undef you get uninitialized warning

$ perl -MData::Dump -we " open $fake, q{<}, \qq{a\nb\nc\n\n}; for(<$fa
+ke>){ dd($_); }"
"a\n"
"b\n"
"c\n"
"\n"
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