The join method is definitely the way to go in this case, but to answer more generally (there was a recent node about this: Don't print on the last loop , but i can't find it at the moment Update Thanks omega_monk!), if you just flip the thought process and prepend commas instead of append them, it becomes: 
my $addrCt = 0;
foreach $address (@content) {
  print ", " if $addrCt++;  # won't be done the first time
  chomp($address);
  print $address;
}

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In reply to Re: Detecting Last line of a file by davidrw
in thread Detecting Last line of a file by Anonymous Monk

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