sed 's/[^,]//g'

sed ':a; s/,/n/6; P; D; ta' roll.txt

sed ':a; s/,/n/6; P; D; ta' roll.txt
'123456789','987651234','129873645','213456789','987612345','543216789'
'432156789','876543291','213465789','542637819','123456','23456'
'22234','3456','7890543','34567891,'2345','567'

perl -MText::CSV -ne '
  BEGIN{$p = Text::CSV->new()}
  @fields = $p->fields() if $p->parse($_);
  do {
    print join ",", splice @fields, 0, 6; print "n";
  } while @fields
' roll.txt
'123456789','987651234','129873645','213456789','987612345','543216789'
'432156789','876543291','213465789','542637819','123456','23456'
'22234','3456','7890543','34567891,'2345','567'