in reply to Removing multiple lines

Adjust -MIN=50 to suit: 

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

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