@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 directory
@subsection Changing the Working Directory
-@UNREVISED
@FIXME{need to read over this node now for continuity; i've switched
things around some.}
@smallexample
@group
--C
-/etc
+-C/etc
passwd
hosts
--C
-/lib
+--directory=/lib
libc.a
@end group
@end smallexample
$ @kbd{tar -c -f foo.tar --files-from list}
@end smallexample
-Notice also that you can only use the short option variant in the file
-list, i.e., always use @option{-C}, not @option{--directory}.
-
The interpretation of @option{--directory} is disabled by
@option{--null} option.
@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}).
@uref{http://www.gnu.org/@/software/@/tar/@/utils/@/tarcat.html, @GNUTAR{}
home page}. It concatenates several archive volumes into a single
valid archive. For example, if you have three volumes named from
-@file{vol-1.tar} to @file{vol-2.tar}, you can do the following to
+@file{vol-1.tar} to @file{vol-3.tar}, you can do the following to
extract them using a third-party @command{tar}:
@smallexample
$ @kbd{tarcat vol-1.tar vol-2.tar vol-3.tar | tar xf -}
@end smallexample
-You could use this approach for many (although not all) PAX
+@cindex Mutli-volume archives in PAX format, extracting using non-GNU tars
+You could use this approach for most (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
-such a way that each part of a split member is extracted as a
+such a way that each part of a split member is extracted to a
different file by @command{tar} implementations that are not aware of
GNU extensions. More specifically, the very first part retains its
original name, and all subsequent parts are named using the pattern:
@item %n @tab Ordinal number of this particular part.
@end multitable
-For example, if, a file @file{var/longfile} was split during archive
+For example, if the file @file{var/longfile} was split during archive
creation between three volumes, and the creator @command{tar} process
had process ID @samp{27962}, then the member names will be:
@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
the command:
@smallexample
-$ @kbd{xsparse @file{cond-file}}
+$ @kbd{xsparse @file{cond-file} @file{out-file}}
@end smallexample
It is often a good idea to run @command{xsparse} in @dfn{dry run} mode
The program behaves the same way all UNIX utilities do: it will keep
quiet unless it has simething important to tell you (e.g. an error
condition or something). If you wish it to produce verbose output,
-similar to that from the dry run mode, give it @option{-v} option:
+similar to that from the dry run mode, use @option{-v} option:
@smallexample
@group
@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
@enumerate 1
@item
-Consult the documentation for your @command{tar} implementation for an
-option that will print @dfn{block numbers} along with the archive
+Consult the documentation of your @command{tar} implementation for an
+option that prints @dfn{block numbers} along with the archive
listing (analogous to @GNUTAR{}'s @option{-R} option). For example,
@command{star} has @option{-block-number}.
@item
-Obtain the verbose listing using the @samp{block number} option, and
-find the position of the sparse member in question and the member
+Obtain verbose listing using the @samp{block number} option, and
+find block numbers of the sparse member in question and the member
immediately following it. For example, running @command{star} on our
archive we obtain:
@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