Hi Nico,
One other suggestion concerning your escaping of underscores "_":
$outfolder = "REPORT_output\_$year\_$mon\_$mday\_\_$hour\_$min
+\_$sec";
The underscore character doesn't need to be escaped like this everywhere in a string. If you were doing so to separate it from the preceding variable (ie. "$year\_$mon" in order to interpolate $year instead of $year_), there's another, more common way to do so which is arguably a little easier to read:
$outfolder = "REPORT_output_${year}_${mon}_${mday}__${hour}_${
+min}_$sec";
This syntax is also often used to separate variables from other chars which could be part of the variable name; eg.:
my $msg = "Hello world";
my $color = 101; # Red background
print "\e[${color}m $msg \e[m\n"; # Embed $color in escape sequence
say
substr+lc crypt(qw $i3 SI$),4,5