[19:07:51.13] C:\test>wc -l 1178116.dat
8000000 1178116.dat

[19:07:54.92] C:\test>head 1178116.dat
ihpfgx  Z
fxbkfh  Z
kqektt  B
zxburh  Z
zpzafy  Z
nvamqp  Z
umpeky  Z
hyfldc  B
qdapmk  Z
ynlfhg  Z

[19:08:07.28] C:\test>perl -anle"$F[1] eq 'Z' and ++$h{$F[0]} }{ print join ' ', $_, $h{ $_ } for keys %h" 1178116.dat >null
[19:08:42.87] C:\test>