That's not how eof works. Did you read the docs? It takes a filehandle as an argument and returns TRUE if the next read on the filehandle will return end of file.

It does *not* take a character as an argument and search for that character.

Your friend was right--you're going to have to use seek and read. Try

seek FH, -1, 2;
read FH, $char, 1;

if ($char eq "#") {
...
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Of course, if the last character of your file is actually a carriage return, this won't work; in that case, you'll need

seek FH, -2, 2;
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