sub filterLog
{ 
    my $input = shift;
    foreach ($input)
    {
       s/ {2,}/ /g;
       s/^((?:\S+ ){3}).+?\[?I\]?:/$1/;
       s/ ?: / /g;
       s/ ACK (\w) / $1 ACK /;
    }
    # $input has been modified...
#.......
}