(tar.info.gz) how to update
Info Catalog
(tar.info.gz) update
4.2.3.1 How to Update an Archive Using '--update'
.................................................
You must use file name arguments with the '--update' ('-u') operation.
If you don't specify any files, 'tar' won't act on any files and won't
tell you that it didn't do anything (which may end up confusing you).
To see the '--update' option at work, create a new file, 'classical',
in your practice directory, and some extra text to the file 'blues',
using any text editor. Then invoke 'tar' with the 'update' operation
and the '--verbose' ('-v') option specified, using the names of all the
files in the 'practice' directory as file name arguments:
$ tar --update -v -f collection.tar blues folk rock classical
blues
classical
$
Because we have specified verbose mode, 'tar' prints out the names of
the files it is working on, which in this case are the names of the
files that needed to be updated. If you run 'tar --list' and look at
the archive, you will see 'blues' and 'classical' at its end. There
will be a total of two versions of the member 'blues'; the one at the
end will be newer and larger, since you added text before updating it.
The reason 'tar' does not overwrite the older file when updating it
is because writing to the middle of a section of tape is a difficult
process. Tapes are not designed to go backward. Media, for
more information about tapes.
'--update' ('-u') is not suitable for performing backups for two
reasons: it does not change directory content entries, and it lengthens
the archive every time it is used. The GNU 'tar' options intended
specifically for backups are more efficient. If you need to run
backups, please consult Backups.
Info Catalog
(tar.info.gz) update
automatically generated by
info2html