"Overwrite Old Files", and revamp that section to make it easier to
follow. "tar" -> "GNU tar" where appropriate. Migrate getdate
documentation into getdate.texi. Fix several minor typos. Describe
TAR_OPTIONS. Describe incompatibility between incremental backups and
--atime-preserve. Describe incompatibility between --verify and other
options. Mention that tar normally removes symbolic links rather than
following them, when extracting a file of the same name.
ae2b051832