# Sorts files in $dir and sets $latest->{file} with newest file.
my $latest = (sort {$b->{mtime} <=> $a->{mtime}}
map {{mtime => -M $_, file => $_}}
<$dir/*>)[-1];
my $newM = (stat $latest->{file})[9];
 
# Sorts files in $dir and sets $oldest->{file} with oldest file.
my $oldest = (sort {$a->{mtime} <=> $b->{mtime}}
map {{mtime => -M $_, file => $_}}
<$dir/*>)[-1];
my $oldM = (stat $oldest->{file})[9];

##</code><code>##

my ($newM, $oldM) = (sort {-M $a <=> -M $b} <./*>)[0,-1];