my $filecontents = $t->get("1.0", "end");
chomp($filecontents);
print TEMP $filecontents;
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or (if you want to eliminate multiple newlines, but leave at least one):

my $filecontents = $t->get("1.0", "end");
$filecontents =~ s/\n+\z/\n/;
print TEMP $filecontents;
[download]