Like pg said, it won't work.

Perhaps a hash is in order? Here's an example:

use strict;

my %numbers;

while (<DATA>) {
    $numbers{$1}++ if /^(\d+)/;
}

print "$_\n" foreach keys %numbers;

__DATA__
123askdjha
1ad
asldhasd
asdklsd123
10
2fer
[download]

Gives:

1
2
10
123
[download]

Update (fixed code): Alternatively, using an array:

use strict;

my @numbers;

while (<DATA>) {
    /^(\d+)/;
    push(@numbers, $1) unless grep(/^$1$/, @numbers) || $1 eq '';
}

print "$_\n" foreach @numbers;

__DATA__
123askdjha
1ad
asldhasd
asdklsd123
10
2fer
[download]

Gives:

123
1
10
2
[download]

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