$OpenBSD: rr.in,v 1.2 2017/07/04 14:53:27 schwarze Exp $
nr-rr - defining and undefining number registers .nr key1 1 .nr key2 2 .nr key3 3 .nr key4 4 .nr key5 5 .rr key1 .rr key3 .rr key5 non-null values: \n[key2] \n[key4]

unset values: \n[key1] \n[key3] \n[key5]