@c Maintenance notes:
@c 1. Pay attention to @FIXME{}s and @UNREVISED{}s
@c 2. Before creating final variant:
-@c 1.1. Run `make check-options' to make sure all options are properly
+@c 2.1. Run `make check-options' to make sure all options are properly
@c documented;
-@c 2.1. Run `make master-menu' (see comment before the master menu).
+@c 2.2. Run `make master-menu' (see comment before the master menu).
@include rendition.texi
@include value.texi
You can use @command{tar} archives in many ways. We want to stress a few
of them: storage, backup, and transportation.
-@FIXME{the following table entries need a bit of work..}
+@FIXME{the following table entries need a bit of work.}
@table @asis
@item Storage
Often, @command{tar} archives are used to store related files for
@node Split Recovery
@subsubsection Extracting Members Split Between Volumes
+@cindex Mutli-volume archives, extracting using non-GNU tars
If a member is split between several volumes of an old GNU format archive
most third party @command{tar} implementation will fail to extract
it. To extract it, use @command{tarcat} program (@pxref{Tarcat}).
$ @kbd{tarcat vol-1.tar vol-2.tar vol-3.tar | tar xf -}
@end smallexample
+@cindex Mutli-volume archives in PAX format, extracting using non-GNU tars
You could use this approach for many (although not all) PAX
format archives as well. However, extracting split members from a PAX
archive is a much easier task, because PAX volumes are constructed in
@node Sparse Recovery
@subsubsection Extracting Sparse Members
+@cindex sparse files, extracting with non-GNU tars
Any @command{tar} implementation will be able to extract sparse members from a
PAX archive. However, the extracted files will be @dfn{condensed},
i.e. any zero blocks will be removed from them. When we restore such
@dfn{holes}) back to their original locations, we call this process
@dfn{expanding} a compressed sparse file.
+@pindex xsparse
To expand a file, you will need a simple auxiliary program called
@command{xsparse}. It is available in source form from
@uref{http://www.gnu.org/@/software/@/tar/@/utils/@/xsparse.html, @GNUTAR{}
home page}.
+@cindex sparse files v.1.0, extracting with non-GNU tars
Let's begin with archive members in @dfn{sparse format
version 1.0}@footnote{@xref{PAX 1}.}, which are the easiest to expand.
The condensed file will contain both file map and file data, so no
@end group
@end smallexample
+@anchor{extracting sparse v.0.x}
+@cindex sparse files v.0.1, extracting with non-GNU tars
+@cindex sparse files v.0.0, extracting with non-GNU tars
An @dfn{extended header} is a special @command{tar} archive header
that precedes an archive member and contains a set of
@dfn{variables}, describing the member properties that cannot be
@option{--label=@var{archive-label}} again in conjunction with the
@option{--append}, @option{--update} or @option{--concatenate} operation.
-@FIXME{This is no longer true: Multivolume archives in @samp{POSIX}
-format can be extracted using any posix-compliant tar
-implementation. The split members can then be recreated from parts
-using a simple shell script. Provide more information about it:}
-Beware that there is @emph{no} real standard about the proper way, for
-a @command{tar} archive, to span volume boundaries. If you have a
-multi-volume created by some vendor's @command{tar}, there is almost
-no chance you could read all the volumes with @GNUTAR{}.
-The converse is also true: you may not expect
-multi-volume archives created by @GNUTAR{} to be
-fully recovered by vendor's @command{tar}. Since there is little
-chance that, in mixed system configurations, some vendor's
-@command{tar} will work on another vendor's machine, and there is a
-great chance that @GNUTAR{} will work on most of
-them, your best bet is to install @GNUTAR{} on all
-machines between which you know exchange of files is possible.
+Notice that multi-volume support is a GNU extension and the archives
+created in this mode should be read only using @GNUTAR{}. If you
+absolutely have to process such archives using a third-party @command{tar}
+implementation, read @ref{Split Recovery}.
@node Tape Files
@subsection Tape Files
projects / chaz / tar / blobdiff