#!/usr/bin/perl 
use strict;
use warnings;

my %files = ();
while (<DATA>) {
    if (/(.{4})/) {
        $files{$1} = 1;
    }
}
foreach my $prefix (keys %files) {
    print "$prefix*\n";
}

__DATA__
abcpwbln08
abcpwbln07
abcpwbnn10
abcpwbnn06
adesicln09
adesicln08
adesicln01
adesicnn05