+++ /dev/null
-@c This is part of the paxutils manual.
-@c Copyright (C) 2006, 2007 Free Software Foundation, Inc.
-@c Written by Sergey Poznyakoff
-@c This file is distributed under GFDL 1.1 or any later version
-@c published by the Free Software Foundation.
-
- Incremental archives keep information about contents of each
-dumped directory in special data blocks called @dfn{dumpdirs}.
-
- Dumpdir is a sequence of entries of the following form:
-
-@smallexample
-@var{C} @var{filename} \0
-@end smallexample
-
-@noindent
-where @var{C} is one of the @dfn{control codes} described below,
-@var{filename} is the name of the file @var{C} operates upon, and
-@samp{\0} represents a nul character (ASCII 0). The white space
-characters were added for readability, real dumpdirs do not contain
-them.
-
- Each dumpdir ends with a single nul character.
-
- The following table describes control codes and their meanings:
-
-@table @samp
-@item Y
-@var{filename} is contained in the archive.
-
-@item N
-@var{filename} was present in the directory at the time the archive
-was made, yet it was not dumped to the archive, because it had not
-changed since the last backup.
-
-@item D
-@var{filename} is a directory.
-
-@item R
-This code requests renaming of the @var{filename} to the name
-specified with the @samp{T} command, that immediately follows it.
-
-@item T
-Specify target file name for @samp{R} command (see below).
-
-@item X
-Specify @dfn{temporary directory} name for a rename operation (see below).
-@end table
-
- Codes @samp{Y}, @samp{N} and @samp{D} require @var{filename} argument
-to be a relative file name to the directory this dumpdir describes,
-whereas codes @samp{R}, @samp{T} and @samp{X} require their argument
-to be an absolute file name.
-
- The three codes @samp{R}, @samp{T} and @samp{X} specify a
-@dfn{renaming operation}. In the simplest case it is:
-
-@smallexample
-R@file{source}\0T@file{dest}\0
-@end smallexample
-
-@noindent
-which means ``rename file @file{source} to file @file{dest}''.
-
- However, there are cases that require using a @dfn{temporary
-directory}. For example, consider the following scenario:
-
-@enumerate 1
-@item
-Previous run dumped a directory @file{foo} which contained the
-following three directories:
-
-@smallexample
-a
-b
-c
-@end smallexample
-
-@item
-They were renamed @emph{cyclically}, so that:
-
-@example
-@file{a} became @file{b}
-@file{b} became @file{c}
-@file{c} became @file{a}
-@end example
-
-@item
-New incremental dump was made.
-@end enumerate
-
- This case cannot be handled by three successive renames, since
-renaming @file{a} to @file{b} will destroy the existing directory.
-To correctly process it, @GNUTAR{} needs a temporary directory, so
-it creates the following dumpdir (newlines have been added for
-readability):
-
-@smallexample
-@group
-Xfoo\0
-Rfoo/a\0T\0
-Rfoo/b\0Tfoo/c\0
-Rfoo/c\0Tfoo/a\0
-R\0Tfoo/a\0
-@end group
-@end smallexample
-
- The first command, @samp{Xfoo\0}, instructs the extractor to create a
-temporary directory in the directory @file{foo}. Second command,
-@samp{Rfoo/aT\0}, says ``rename file @file{foo/a} to the temporary
-directory that has just been created'' (empty file name after a
-command means use temporary directory). Third and fourth commands
-work as usual, and, finally, the last command, @samp{R\0Tfoo/a\0}
-tells tar to rename the temporary directory to @file{foo/a}.
-
- The exact placement of a dumpdir in the archive depends on the
-archive format (@pxref{Formats}):
-
-@itemize
-@item PAX archives
-
-In PAX archives, dumpdir is stored in the extended header of the
-corresponding directory, in variable @code{GNU.dumpdir}.
-
-@item GNU and old GNU archives
-
-These formats implement special header type @samp{D}, which is similar
-to ustar header @samp{5} (directory), except that it precedes a data
-block containing the dumpdir.
-@end itemize
-
-@c End of dumpdir.texi
projects / debian / tar / blobdiff