Your specification is quite loose, so this may not be what you're after :(

$| = 1; # autoflush
print "Enter last number: ";
chomp( my $last = <STDIN> );
print join( ", ", 1 .. $last ), "\n";
#Output:
#1, 2, 3, 4, 5
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Update: Just in case you think I disagree with Joost, you do want

use strict;
use warnings;
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near the start of your script.

Update^2: I've done no error checking (negative number, not a number, blank line etc), thanks ww. I'll leave that as an exercise. Oh, and chomp isn't needed either.