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my @f = sort { -M $b <=> -M $a } readdir $d;
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my @file_list = sort { -M $b <=> -M $a }
grep -f, readdir $dir_handle;
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unlink @f[-0,1] if @f > 20;
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use File::Spec 'catfile';
unlink map catfile($dir, $_), @f[0,1]
if @file_list > 20;
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use File::Spec 'catfile';
opendir my $dir_handle, $dir
or die "Couldn't open '$dir': $!";
my @file_list = sort { -M $b <=> -M $a }
grep -f, readdir $dir_handle;
unlink map catfile($dir, $_), @f[0,1]
if @file_list > 20;