use strict;
use warnings;
use Data::Dump;

my @window;

push @window, scalar <DATA> for 1..5; 				    # init

while (my $line = <DATA>) {
    push @window, $line;
    chomp @window;
    
    if( $window[3] =~ m/[^\d]+\d+/ ){
         dd \@window;
    }

    shift @window;
}



__END__
alpha
beta
something
a07607
b-alpha
b-beta
b-something
b-something else
c-alpha
c-beta
c-somethin
a9706
d-alpha
d-beta
d-something
d-something else