$# (not #$) refers to the index of the last element of an array.

The "at-sign" sigil (@) is used when you refer to two or more elements of an array. If you are accessing (or referring to) a single element of an array, then the "dollar-sign" ($) sigil is used.

For example:

my @foo = qw/a b c/;
print "$foo[1]\n";      # Prints b
print "@foo\n";         # Prints a b c
print "$foo[$#foo]\n";  # Prints c (but you would probably never do th
+is)
print "$foo[-1]\n";     # Also prints c (a better way than the previou
+s) 
print "@foo[0,2]\n";    # Prints a c
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Cheers,
Darren :)