GNU tar has some predefined defaults that are used when you do not
explicitely specify another values. To obtain a list of such
defaults, use --show-defaults option. This will output the
values in the form of tar command line options:
tar --show-defaults
--format=gnu -f- -b20 --rmt-command=/etc/rmt --rsh-command=/usr/bin/rsh
The above output shows that this version of GNU tar defaults to
using ‘gnu’ archive format (see Formats), it uses standard
output as the archive, if no --file option has been given
(see file tutorial), the default blocking factor is 20
(see Blocking Factor). It also shows the default locations where
tar will look for rmt and rsh binaries.
Published under the terms of the GNU General Public License
