sort uses the "global" variables $a and $b as comparing algrothm for the sort; you can't use other variables instead

if you try to use my-variables instead, you are useing other variables and it won't work

sort is the reason why $a and $b aren't checked by use strict; so IMHO it's a good idea to reserve these variables to sort

use strict;
my @home = (1, 2, 23, 10, 9);
print map { "$_\n" } sort { $a <=> $b } @home;
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