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tar progress
Typically, tar performs most operations without reporting any
information to the user except error messages. When using tar
with many options, particularly ones with complicated or
difficult-to-predict behavior, it is possible to make serious mistakes.
tar provides several options that make observing tar
easier. These options cause tar to print information as it
progresses in its job, and you might want to use them just for being
more careful about what is going on, or merely for entertaining
yourself. If you have encountered a problem when operating on an
archive, however, you may need more information than just an error
message in order to solve the problem. The following options can be
helpful diagnostic tools.
Normally, the `--list' (`-t') command to list an archive
prints just the file names (one per line) and the other commands are
silent. When used with most operations, the `--verbose' (`-v') option causes tar to print the name of each file or
archive member as it is processed. This and the other options which
make tar print status information can be useful in monitoring
tar.
With `--create' (`-c') or `--extract' (`-x'),
`--verbose' (`-v') used once just prints the names of the
files or members as they are processed. Using it twice causes
tar to print a longer listing (reminiscent of `ls -l') for
each member. Since `--list' (`-t') already prints the names
of the members, `--verbose' (`-v') used once with
`--list' (`-t') causes tar to print an `ls -l'
type listing of the files in the archive. The following examples both
extract members with long list output:
tar --extract --file=archive.tar --verbose --verbose tar xvv archive.tar
Verbose output appears on the standard output except when an archive is
being written to the standard output, as with `tar --create
--file=- --verbose' (`tar cfv -', or even `tar cv'---if the
installer let standard output be the default archive). In that case
tar writes verbose output to the standard error stream.
The `--totals' option--which is only meaningful when used with
`--create' (`-c')---causes tar to print the total
amount written to the archive, after it has been fully created.
The `--checkpoint' option prints an occasional message as
tar reads or writes the archive. In fact, it print directory
names while reading the archive. It is designed for those who don't
need the more detailed (and voluminous) output of `--record-number' (`-R'), but do want visual confirmation that tar is actually
making forward progress.
FIXME: There is some confusion here. It seems that -R once wrote a FIXME: message at `every' block read or written.
The `--show-omitted-dirs' option, when reading an archive--with `--list' (`-t') or `--extract' (`-x'), for example--causes a message to be printed for each directory in the archive which is skipped. This happens regardless of the reason for skipping: the directory might not have been named on the command line (implicitly or explicitly), it might be excluded by the use of the `--exclude=pattern' option, or some other reason.
If `--record-number' (`-R') is used, tar prints, along
with every message it would normally produce, the record number within
the archive where the message was triggered. This option is especially
useful when reading damaged archives, since it helps pinpoint the
damaged sections. It can also be used with `--list' (`-t')
when listing a file-system backup tape, allowing you to choose among
several backup tapes when retrieving a file later, in favor of the tape
where the file appears earliest (closest to the front of the tape).
FIXME: xref when the node name is set and the backup section written
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