$ ll xx.csv
12862169 -rw-rw-rw- 1 merijn users 415423 Sep  6 16:00 xx.csv
$ perl -MDBI -wE'say DBI->connect("dbi:CSV:f_ext=.csv")->selectrow_arrayref("select count(*) from xx")->[0]," rows in fs"'
8739 rows in fs