Simplified array insert, in case you do need the list for later processing. Also corrected typo in last statement (and updated to fix my own to end on null input).

#!/perl/ -w
use strict;

my (@nums,$input); #array of numbers

while(<>){
  chomp($input=$_);
  last if ($input eq '');
  push @nums, $input;
}

@nums= sort {$a<=>$b} @nums;

print "\nminimum number: $nums[0]";
print "\nmaximum number: $nums[$#nums]";
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