* Changes::
* Configuring Help Summary::
+* Fixing Snapshot Files::
* Tar Internals::
* Genfile::
* Free Software Needs Free Documentation::
Controlling the Archive Format
-* Portability:: Making @command{tar} Archives More Portable
* Compression:: Using Less Space through Compression
* Attributes:: Handling File Attributes
+* Portability:: Making @command{tar} Archives More Portable
* cpio:: Comparison of @command{tar} and @command{cpio}
+Using Less Space through Compression
+
+* gzip:: Creating and Reading Compressed Archives
+* sparse:: Archiving Sparse Files
+
Making @command{tar} Archives More Portable
* Portable Names:: Portable Names
* Split Recovery:: Members Split Between Volumes
* Sparse Recovery:: Sparse Members
-Using Less Space through Compression
-
-* gzip:: Creating and Reading Compressed Archives
-* sparse:: Archiving Sparse Files
-
Tapes and Other Archive Media
* Device:: Device selection and switching
(see --info-script)
-@opsummary{seek}
-@item --seek
-@itemx -n
-
-Assume that the archive media supports seeks to arbitrary
-locations. Usually @command{tar} determines automatically whether
-the archive can be seeked or not. This option is intended for use
-in cases when such recognition fails.
-
@opsummary{newer}
@item --newer=@var{date}
@itemx --after-date=@var{date}
This option does not affect extraction from archives.
-@opsummary{transform}
-@item --transform=@var{sed-expr}
-
-Transform file or member names using @command{sed} replacement expression
-@var{sed-expr}. For example,
-
-@smallexample
-$ @kbd{tar cf archive.tar --transform 's,^\./,usr/,' .}
-@end smallexample
-
-@noindent
-will add to @file{archive} files from the current working directory,
-replacing initial @samp{./} prefix with @samp{usr/}. For the detailed
-discussion, @xref{transform}.
-
-To see transformed member names in verbose listings, use
-@option{--show-transformed-names} option
-(@pxref{show-transformed-names}).
-
-@opsummary{quote-chars}
-@item --quote-chars=@var{string}
-Always quote characters from @var{string}, even if the selected
-quoting style would not quote them (@pxref{quoting styles}).
-
-@opsummary{quoting-style}
-@item --quoting-style=@var{style}
-Set quoting style to use when printing member and file names
-(@pxref{quoting styles}). Valid @var{style} values are:
-@code{literal}, @code{shell}, @code{shell-always}, @code{c},
-@code{escape}, @code{locale}, and @code{clocale}. Default quoting
-style is @code{escape}, unless overridden while configuring the
-package.
-
@opsummary{pax-option}
@item --pax-option=@var{keyword-list}
This option is meaningful only with @acronym{POSIX.1-2001} archives
Specifying this option instructs @command{tar} that it should use the
permissions directly from the archive. @xref{Setting Access Permissions}.
+@opsummary{quote-chars}
+@item --quote-chars=@var{string}
+Always quote characters from @var{string}, even if the selected
+quoting style would not quote them (@pxref{quoting styles}).
+
+@opsummary{quoting-style}
+@item --quoting-style=@var{style}
+Set quoting style to use when printing member and file names
+(@pxref{quoting styles}). Valid @var{style} values are:
+@code{literal}, @code{shell}, @code{shell-always}, @code{c},
+@code{escape}, @code{locale}, and @code{clocale}. Default quoting
+style is @code{escape}, unless overridden while configuring the
+package.
+
@opsummary{read-full-records}
@item --read-full-records
@itemx -B
(See @option{--preserve-permissions}; @pxref{Setting Access Permissions}.)
+@opsummary{seek}
+@item --seek
+@itemx -n
+
+Assume that the archive media supports seeks to arbitrary
+locations. Usually @command{tar} determines automatically whether
+the archive can be seeked or not. This option is intended for use
+in cases when such recognition fails.
+
@opsummary{show-defaults}
@item --show-defaults
rather than the data modification time stored in the archive.
@xref{Data Modification Times}.
+@opsummary{transform}
+@item --transform=@var{sed-expr}
+
+Transform file or member names using @command{sed} replacement expression
+@var{sed-expr}. For example,
+
+@smallexample
+$ @kbd{tar cf archive.tar --transform 's,^\./,usr/,' .}
+@end smallexample
+
+@noindent
+will add to @file{archive} files from the current working directory,
+replacing initial @samp{./} prefix with @samp{usr/}. For the detailed
+discussion, @xref{transform}.
+
+To see transformed member names in verbose listings, use
+@option{--show-transformed-names} option
+(@pxref{show-transformed-names}).
+
@opsummary{uncompress}
@item --uncompress
with the @option{--atime-preserve=replace} option), or if you set the clock
backwards.
+@cindex Device numbers, using in incremental backups
Metadata stored in snapshot files include device numbers, which,
obviously is supposed to be a non-volatile value. However, it turns
out that NFS devices have undependable values when an automounter
comparing directories; this is fairly gross, but there does not seem
to be a better way to go.
+If you are using the @i{Linux} kernel, the device numbers can also
+change when upgrading to some newer versions of the kernel. This can
+cause the next backup to be full backup on the affected filesystems.
+@xref{Fixing Snapshot Files}, for the information on how to handle this case.
+
Note that incremental archives use @command{tar} extensions and may
not be readable by non-@acronym{GNU} versions of the @command{tar} program.
Right margin of the text output. Used for wrapping.
@end deftypevr
+@node Fixing Snapshot Files
+@appendix Fixing Snapshot Files
+@include tar-snapshot-edit.texi
+
@node Tar Internals
@appendix Tar Internals
@include intern.texi
projects / chaz / tar / blobdiff