perl -snle"print if 1+index$_,substr($last,0,$MIN),0;$last=$_" -- -MIN=50 junk
"SimpsonH","Homer","Simpson","NULL","648","0","218 555","Nuclear Control","Nuclear Operator","SimpsonM"
"SimpsonB","Bart","Simpson","NULL","748","0","218 555","Springfield Elementary","Student","SimpsonH"