Region Commands
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Vi operators like `d', `c' etc. are usually used in combination with
motion commands. It is now possible to use current region as the
argument to these operators. (A "region" is a part of buffer delimited
by point and mark.) The key `r' is used for this purpose. Thus `d r'
will delete the current region. If `R' is used instead of `r' the
region will first be enlarged so that it will become the smallest
region containing the original region and consisting of whole lines.
Thus `m . d R' will have the same effect as `d d'.