thanks guys for help,here is my take(from your ideas,incorporating incompatibilities vim<>sed)

i needed to delete lines(and not keep empty spaces) in owntracks logging where accuracy was higher than 400(i might refine later) inside .rec files:

sed -Eiz '/^.*\"acc\"\:([4-9][0-9][0-9])|([0-9]{4,})\}/d' *.rec

hope this helps someone edit: -E for [0-9] matching,-i for inplace edit,-z probably not usefull