This should work (I don't have perl on the pc I'm on now, but it should work). Each of the last lines should be in @lines (this way also uses up less memory).

my @files = ("/mnt/csphil/home/fburns/domereports/Weekly_Reports/de-nj
+-md", "/mnt/csphil/home/fburns/domereports/Weekly_Reports/pa_only", "
+/mnt/csphil/home/fburns/domereports/Weekly_Reports/phila_market"); 
my $file;
my (@data, @lines);

for $file (@files){
    open (FH, $file) || die "Unable to open file $file\n";
    @data = <FH>;
    close (FH);
    push (@lines, $data[$#data]);
}
undef @data; # Don't waste memory
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