# ...
# 1110785a

my $days;

sub deleteData {

if (@ARGV) {
    $days = $ARGV[0];
    say $days;
}else{
    say "n\t Usage: 1110785.pl n \n";
}

$days = shift (@ARGV);
say "days in sub: $days";
#   ...
}

deleteData;
say "back in main.";

=head EXECUTION

C:\>D:\_Perl_\PMonks\1110785a.pl 8
8
days in sub: 8
back in main.

=cut