@smallbook
@c %**end of header
-@c ======================================================================
-@c This document has three levels of rendition: PUBLISH, DISTRIB or PROOF,
-@c as decided by @set symbols. The PUBLISH rendition does not show
-@c notes or marks asking for revision. Most users will prefer having more
-@c information, even if this information is not fully revised for adequacy,
-@c so DISTRIB is the default for tar distributions. The PROOF rendition
-@c show all marks to the point of ugliness, but is nevertheless useful to
-@c those working on the manual itself.
-@c ======================================================================
-
-@ifclear PUBLISH
-@ifclear DISTRIB
-@ifclear PROOF
-@set DISTRIB
-@end ifclear
-@end ifclear
-@end ifclear
-
-@ifset PUBLISH
-@set RENDITION The book, version
-@end ifset
-
-@ifset DISTRIB
-@set RENDITION FTP release, version
-@end ifset
-
-@ifset PROOF
-@set RENDITION Proof reading version
-@end ifset
-
-@c ---------------------------------------------------------------------
-@c The @FIXME's, @UNREVISED and @c comments are part Fran@,{c}ois's work
-@c plan. These annotations are somewhat precious to him; he asks that I
-@c do not alter them inconsiderately. Much work is needed for GNU tar
-@c internals (the sources, the programs themselves). Revising the
-@c adequacy of the manual while revising the sources, and cleaning them
-@c both at the same time, is a good way to proceed.
-@c ---------------------------------------------------------------------
-
-@c Output marks for nodes needing revision, but not in PUBLISH rendition.
-
-@macro UNREVISED
-@ifclear PUBLISH
-@quotation
-@emph{(This message will disappear, once this node revised.)}
-@end quotation
-@end ifclear
-@end macro
-
-@c Output various FIXME information only in PROOF rendition.
-
-@macro FIXME{string}
-@allow-recursion
-@quote-arg
-@ifset PROOF
-@strong{<FIXME>} \string\ @strong{</>}
-@end ifset
-
-@end macro
-
-@macro FIXME-ref{string}
-@quote-arg
-@ifset PROOF
-@strong{<REF>} \string\ @strong{</>}
-@end ifset
-
-@end macro
-
-@macro FIXME-pxref{string}
-@quote-arg
-@ifset PROOF
-@strong{<PXREF>} \string\ @strong{</>}
-@end ifset
-
-@end macro
-
-@macro FIXME-xref{string}
-@quote-arg
-@ifset PROOF
-@strong{<XREF>} \string\ @strong{</>}
-@end ifset
-
-@end macro
-
-@c @macro option{entry}
-@c @quote-arg
-@c @opindex{--\entry\}
-@c @value{\entry\}
-@c @end macro
-
-@macro GNUTAR
-@acronym{GNU} @command{tar}
-@end macro
-
-@set op-absolute-names @kbd{--absolute-names} (@kbd{-P})
-@set ref-absolute-names @ref{absolute}
-@set xref-absolute-names @xref{absolute}
-@set pxref-absolute-names @pxref{absolute}
-
-@set op-after-date @kbd{--after-date=@var{date}} (@kbd{--newer=@var{date}}, @kbd{-N @var{date}})
-@set ref-after-date @ref{after}
-@set xref-after-date @xref{after}
-@set pxref-after-date @pxref{after}
-
-@set op-append @kbd{--append} (@kbd{-r})
-@set ref-append @ref{add}
-@set xref-append @xref{add}
-@set pxref-append @pxref{add}
-
-@set op-atime-preserve @kbd{--atime-preserve}
-@set ref-atime-preserve @ref{Attributes}
-@set xref-atime-preserve @xref{Attributes}
-@set pxref-atime-preserve @pxref{Attributes}
-
-@set op-backup @kbd{--backup}
-@set ref-backup @ref{Backup options}
-@set xref-backup @xref{Backup options}
-@set pxref-backup @pxref{Backup options}
-
-@set op-block-number @kbd{--block-number} (@kbd{-R})
-@set ref-block-number @ref{verbose}
-@set xref-block-number @xref{verbose}
-@set pxref-block-number @pxref{verbose}
-
-@set op-blocking-factor @kbd{--blocking-factor=@var{512-size}} (@kbd{-b @var{512-size}})
-@set ref-blocking-factor @ref{Blocking Factor}
-@set xref-blocking-factor @xref{Blocking Factor}
-@set pxref-blocking-factor @pxref{Blocking Factor}
-
-@set op-bzip2 @kbd{--bzip2} (@kbd{-j})
-@set ref-bzip2 @ref{gzip}
-@set xref-bzip2 @xref{gzip}
-@set pxref-bzip2 @pxref{gzip}
-
-@set op-check-links @kbd{--check-links} (@kbd{-l})
-@set ref-check-links @ref{--check-links}
-@set xref-check-links @xref{--check-links}
-@set pxref-check-links @pxref{--check-links}
-
-@set op-checkpoint @kbd{--checkpoint}
-@set ref-checkpoint @ref{verbose}
-@set xref-checkpoint @xref{verbose}
-@set pxref-checkpoint @pxref{verbose}
-
-@set op-check-links @kbd{--check-links}
-
-@set op-compare @kbd{--compare} (@kbd{--diff}, @kbd{-d})
-@set ref-compare @ref{compare}
-@set xref-compare @xref{compare}
-@set pxref-compare @pxref{compare}
-
-@set op-compress @kbd{--compress} (@kbd{--uncompress}, @kbd{-Z})
-@set ref-compress @ref{gzip}
-@set xref-compress @xref{gzip}
-@set pxref-compress @pxref{gzip}
-
-@set op-concatenate @kbd{--concatenate} (@kbd{--catenate}, @kbd{-A})
-@set ref-concatenate @ref{concatenate}
-@set xref-concatenate @xref{concatenate}
-@set pxref-concatenate @pxref{concatenate}
-
-@set op-create @kbd{--create} (@kbd{-c})
-@set ref-create @ref{create}
-@set xref-create @xref{create}
-@set pxref-create @pxref{create}
-
-@set op-delete @kbd{--delete}
-@set ref-delete @ref{delete}
-@set xref-delete @xref{delete}
-@set pxref-delete @pxref{delete}
-
-@set op-dereference @kbd{--dereference} (@kbd{-h})
-@set ref-dereference @ref{dereference}
-@set xref-dereference @xref{dereference}
-@set pxref-dereference @pxref{dereference}
-
-@set op-directory @kbd{--directory=@var{directory}} (@kbd{-C @var{directory}})
-@set ref-directory @ref{directory}
-@set xref-directory @xref{directory}
-@set pxref-directory @pxref{directory}
-
-@set op-exclude @kbd{--exclude=@var{pattern}}
-@set ref-exclude @ref{exclude}
-@set xref-exclude @xref{exclude}
-@set pxref-exclude @pxref{exclude}
-
-@set op-exclude-from @kbd{--exclude-from=@var{file-of-patterns}} (@kbd{-X @var{file-of-patterns}})
-@set ref-exclude-from @ref{exclude}
-@set xref-exclude-from @xref{exclude}
-@set pxref-exclude-from @pxref{exclude}
-
-@set op-extract @kbd{--extract} (@kbd{--get}, @kbd{-x})
-@set ref-extract @ref{extract}
-@set xref-extract @xref{extract}
-@set pxref-extract @pxref{extract}
-
-@set op-file @kbd{--file=@var{archive-name}} (@kbd{-f @var{archive-name}})
-@set ref-file @ref{file}
-@set xref-file @xref{file}
-@set pxref-file @pxref{file}
-
-@set op-files-from @kbd{--files-from=@var{file-of-names}} (@kbd{-T @var{file-of-names}})
-@set ref-files-from @ref{files}
-@set xref-files-from @xref{files}
-@set pxref-files-from @pxref{files}
-
-@set op-force-local @kbd{--force-local}
-@set ref-force-local @ref{file}
-@set xref-force-local @xref{file}
-@set pxref-force-local @pxref{file}
-
-@set op-group @kbd{--group=@var{group}}
-@set ref-group @ref{Option Summary}
-@set xref-group @xref{Option Summary}
-@set pxref-group @pxref{Option Summary}
-
-@set op-gzip @kbd{--gzip} (@kbd{--gunzip}, @kbd{--ungzip}, @kbd{-z})
-@set ref-gzip @ref{gzip}
-@set xref-gzip @xref{gzip}
-@set pxref-gzip @pxref{gzip}
-
-@set op-help @kbd{--help}
-@set ref-help @ref{help}
-@set xref-help @xref{help}
-@set pxref-help @pxref{help}
-
-@set op-ignore-failed-read @kbd{--ignore-failed-read}
-@set ref-ignore-failed-read @ref{create options}
-@set xref-ignore-failed-read @xref{create options}
-@set pxref-ignore-failed-read @pxref{create options}
-
-@set op-ignore-zeros @kbd{--ignore-zeros} (@kbd{-i})
-@set ref-ignore-zeros @ref{Reading}
-@set xref-ignore-zeros @xref{Reading}
-@set pxref-ignore-zeros @pxref{Reading}
-
-@set op-incremental @kbd{--incremental} (@kbd{-G})
-@set ref-incremental @ref{Inc Dumps}
-@set xref-incremental @xref{Inc Dumps}
-@set pxref-incremental @pxref{Inc Dumps}
-
-@set op-info-script @kbd{--info-script=@var{script-name}} (@kbd{--new-volume-script=@var{script-name}}, @kbd{-F @var{script-name}})
-@set ref-info-script @ref{Multi-Volume Archives}
-@set xref-info-script @xref{Multi-Volume Archives}
-@set pxref-info-script @pxref{Multi-Volume Archives}
-
-@set op-interactive @kbd{--interactive} (@kbd{-w})
-@set ref-interactive @ref{interactive}
-@set xref-interactive @xref{interactive}
-@set pxref-interactive @pxref{interactive}
-
-@set op-keep-old-files @kbd{--keep-old-files} (@kbd{-k})
-@set ref-keep-old-files @ref{Keep Old Files}
-@set xref-keep-old-files @xref{Keep Old Files}
-@set pxref-keep-old-files @pxref{Keep Old Files}
-
-@set op-keep-newer-files @kbd{--keep-old-files}
-@set ref-keep-newer-files @ref{Keep Newer Files}
-@set xref-keep-newer-files @xref{Keep Newer Files}
-@set pxref-keep-newer-files @pxref{Keep Newer Files}
-
-@set op-label @kbd{--label=@var{archive-label}} (@kbd{-V @var{archive-label}})
-@set ref-label @ref{label}
-@set xref-label @xref{label}
-@set pxref-label @pxref{label}
-
-@set op-list @kbd{--list} (@kbd{-t})
-@set ref-list @ref{list}
-@set xref-list @xref{list}
-@set pxref-list @pxref{list}
-
-@set op-listed-incremental @kbd{--listed-incremental=@var{snapshot-file}} (@kbd{-g @var{snapshot-file}})
-@set ref-listed-incremental @ref{Inc Dumps}
-@set xref-listed-incremental @xref{Inc Dumps}
-@set pxref-listed-incremental @pxref{Inc Dumps}
-
-@set op-mode @kbd{--mode=@var{permissions}}
-@set ref-mode @ref{Option Summary}
-@set xref-mode @xref{Option Summary}
-@set pxref-mode @pxref{Option Summary}
-
-@set op-multi-volume @kbd{--multi-volume} (@kbd{-M})
-@set ref-multi-volume @ref{Multi-Volume Archives}
-@set xref-multi-volume @xref{Multi-Volume Archives}
-@set pxref-multi-volume @pxref{Multi-Volume Archives}
-
-@set op-newer-mtime @kbd{--newer-mtime=@var{date}}
-@set ref-newer-mtime @ref{after}
-@set xref-newer-mtime @xref{after}
-@set pxref-newer-mtime @pxref{after}
-
-@set op-no-recursion @kbd{--no-recursion}
-@set ref-no-recursion @ref{recurse}
-@set xref-no-recursion @xref{recurse}
-@set pxref-no-recursion @pxref{recurse}
-
-@set op-no-same-owner @kbd{--no-same-owner} (@kbd{-o})
-@set ref-no-same-owner @ref{Attributes}
-@set xref-no-same-owner @xref{Attributes}
-@set pxref-no-same-owner @pxref{Attributes}
-
-@set op-no-same-permissions @kbd{--no-same-permissions}
-@set ref-no-same-permissions @ref{Attributes}
-@set xref-no-same-permissions @xref{Attributes}
-@set pxref-no-same-permissions @pxref{Attributes}
-
-@set op-null @kbd{--null}
-@set ref-null @ref{files}
-@set xref-null @xref{files}
-@set pxref-null @pxref{files}
-
-@set op-numeric-owner @kbd{--numeric-owner}
-@set ref-numeric-owner @ref{Attributes}
-@set xref-numeric-owner @xref{Attributes}
-@set pxref-numeric-owner @pxref{Attributes}
-
-@set op-occurrence @kbd{--occurrence}
-@set ref-occurrence @ref{--occurrence}
-@set xref-occurrence @xref{--occurrence}
-@set pxref-occurrence @pxref{--occurrence}
-
-@set op-old-archive @kbd{--old-archive} (@kbd{-o})
-@set ref-old-archive @ref{old}
-@set xref-old-archive @xref{old}
-@set pxref-old-archive @pxref{old}
-
-@set op-one-file-system @kbd{--one-file-system} (@kbd{-l})
-@set ref-one-file-system @ref{one}
-@set xref-one-file-system @xref{one}
-@set pxref-one-file-system @pxref{one}
-
-@set op-overwrite @kbd{--overwrite}
-@set ref-overwrite @ref{Overwrite Old Files}
-@set xref-overwrite @xref{Overwrite Old Files}
-@set pxref-overwrite @pxref{Overwrite Old Files}
-
-@set op-owner @kbd{--owner=@var{user}}
-@set ref-owner @ref{Option Summary}
-@set xref-owner @xref{Option Summary}
-@set pxref-owner @pxref{Option Summary}
-
-@set op-format @kbd{--format} (@kbd{-H})
-@set ref-format @ref{format}
-@set xref-format @xref{format}
-@set pxref-format @pxref{format}
-
-@set op-format-v7 @kbd{--format=v7}
-@set op-format-gnu @kbd{--format=gnu}
-@set op-format-oldgnu @kbd{--format=oldgnu}
-@set op-format-posix @kbd{--format=posix}
-@set op-format-ustar @kbd{--format=ustar}
-
-@set op-posix @kbd{--posix}
-@set ref-posix @ref{posix}
-@set xref-posix @xref{posix}
-@set pxref-posix @pxref{posix}
-
-@set op-preserve @kbd{--preserve}
-@set ref-preserve @ref{Attributes}
-@set xref-preserve @xref{Attributes}
-@set pxref-preserve @pxref{Attributes}
-
-@set op-record-size @kbd{--record-size=@var{size}}
-@set ref-record-size @ref{Blocking}
-@set xref-record-size @xref{Blocking}
-@set pxref-record-size @pxref{Blocking}
-
-@set op-recursive-unlink @kbd{--recursive-unlink}
-@set ref-recursive-unlink @ref{Writing}
-@set xref-recursive-unlink @xref{Writing}
-@set pxref-recursive-unlink @pxref{Writing}
-
-@set op-read-full-records @kbd{--read-full-records} (@kbd{-B})
-@set ref-read-full-records @ref{Blocking}
-@set xref-read-full-records @xref{Blocking}
-@set pxref-read-full-records @pxref{Blocking}
-@c FIXME: or should it be Reading, or Blocking Factor
-
-@set op-remove-files @kbd{--remove-files}
-@set ref-remove-files @ref{Writing}
-@set xref-remove-files @xref{Writing}
-@set pxref-remove-files @pxref{Writing}
-
-@set op-rmt-command @kbd{rmt-command=@var{command}}
-@set op-rsh-command @kbd{rsh-command=@var{command}}
-
-@set op-same-order @kbd{--same-order} (@kbd{--preserve-order}, @kbd{-s})
-@set ref-same-order @ref{Scarce}
-@set xref-same-order @xref{Scarce}
-@set pxref-same-order @pxref{Scarce}
-@c FIXME: or should it be Reading, or Attributes?
-
-@set op-same-owner @kbd{--same-owner}
-@set ref-same-owner @ref{Attributes}
-@set xref-same-owner @xref{Attributes}
-@set pxref-same-owner @pxref{Attributes}
-
-@set op-same-permissions @kbd{--same-permissions} (@kbd{--preserve-permissions}, @kbd{-p})
-@set ref-same-permissions @ref{Attributes}
-@set xref-same-permissions @xref{Attributes}
-@set pxref-same-permissions @pxref{Attributes}
-@c FIXME: or should it be Writing?
-
-@set op-show-omitted-dirs @kbd{--show-omitted-dirs}
-@set ref-show-omitted-dirs @ref{verbose}
-@set xref-show-omitted-dirs @xref{verbose}
-@set pxref-show-omitted-dirs @pxref{verbose}
-
-@set op-sparse @kbd{--sparse} (@kbd{-S})
-@set ref-sparse @ref{sparse}
-@set xref-sparse @xref{sparse}
-@set pxref-sparse @pxref{sparse}
-
-@set op-starting-file @kbd{--starting-file=@var{name}} (@kbd{-K @var{name}})
-@set ref-starting-file @ref{Scarce}
-@set xref-starting-file @xref{Scarce}
-@set pxref-starting-file @pxref{Scarce}
-
-@set op-strip-components @kbd{--strip-components}
-@set ref-strip-components @ref{--strip-components}
-@set xref-strip-components @xref{--strip-components}
-@set pxref-strip-components @pxref{--strip-components}
-
-@set op-suffix @kbd{--suffix=@var{suffix}}
-@set ref-suffix @ref{Backup options}
-@set xref-suffix @xref{Backup options}
-@set pxref-suffix @pxref{Backup options}
-
-@set op-tape-length @kbd{--tape-length=@var{1024-size}} (@kbd{-L @var{1024-size}})
-@set ref-tape-length @ref{Using Multiple Tapes}
-@set xref-tape-length @xref{Using Multiple Tapes}
-@set pxref-tape-length @pxref{Using Multiple Tapes}
-
-@set op-to-stdout @kbd{--to-stdout} (@kbd{-O})
-@set ref-to-stdout @ref{Writing}
-@set xref-to-stdout @xref{Writing}
-@set pxref-to-stdout @pxref{Writing}
-
-@set op-totals @kbd{--totals}
-@set ref-totals @ref{verbose}
-@set xref-totals @xref{verbose}
-@set pxref-totals @pxref{verbose}
-
-@set op-touch @kbd{--touch} (@kbd{-m})
-@set ref-touch @ref{Writing}
-@set xref-touch @xref{Writing}
-@set pxref-touch @pxref{Writing}
-
-@set op-unlink-first @kbd{--unlink-first} (@kbd{-U})
-@set ref-unlink-first @ref{Writing}
-@set xref-unlink-first @xref{Writing}
-@set pxref-unlink-first @pxref{Writing}
-
-@set op-update @kbd{--update} (@kbd{-u})
-@set ref-update @ref{update}
-@set xref-update @xref{update}
-@set pxref-update @pxref{update}
-
-@set op-use-compress-prog @kbd{--use-compress-prog=@var{program}}
-@set ref-use-compress-prog @ref{gzip}
-@set xref-use-compress-prog @xref{gzip}
-@set pxref-use-compress-prog @pxref{gzip}
-
-@set op-verbose @kbd{--verbose} (@kbd{-v})
-@set ref-verbose @ref{verbose}
-@set xref-verbose @xref{verbose}
-@set pxref-verbose @pxref{verbose}
-
-@set op-verify @kbd{--verify} (@kbd{-W})
-@set ref-verify @ref{verify}
-@set xref-verify @xref{verify}
-@set pxref-verify @pxref{verify}
-
-@set op-version @kbd{--version}
-@set ref-version @ref{help}
-@set xref-version @xref{help}
-@set pxref-version @pxref{help}
-
-@set op-volno-file @kbd{--volno-file=@var{file-of-number}}
-@set ref-volno-file @ref{Using Multiple Tapes}
-@set xref-volno-file @xref{Using Multiple Tapes}
-@set pxref-volno-file @pxref{Using Multiple Tapes}
-
-@set op-seek @kbd{--seek}
-@set ref-seek @ref{seek}
-@set xref-seek @xref{seek}
-@set pxref-seek @pxref{seek}
+@include rendition.texi
+@include value.texi
@c Put everything in one index (arbitrarily chosen to be the concept index).
@syncodeindex fn cp
* delete::
* compare::
-How to Add Files to Existing Archives: @code{--append}
+How to Add Files to Existing Archives: @option{--append}
* appending files:: Appending Files to an Archive
* multiple::
* how to update::
-Options Used by @code{--create}
+Options Used by @option{--create}
* Ignore Failed Read::
-Options Used by @code{--extract}
+Options Used by @option{--extract}
* Reading:: Options to Help Read Archives
* Writing:: Changing How @command{tar} Writes Files
@item Use of short option @option{-l}
Earlier versions of @GNUTAR{} understood @option{-l} option as a
-synonym for @samp{--one-file-system}. Such usage is deprecated.
+synonym for @option{--one-file-system}. Such usage is deprecated.
For compatibility with other implementations future versions of
@GNUTAR{} will understand this option as a synonym for
@option{--check-links}.
@chapter Tutorial Introduction to @command{tar}
This chapter guides you through some basic examples of three @command{tar}
-operations: @samp{--create}, @samp{--list}, and @samp{--extract}. If
+operations: @option{--create}, @option{--list}, and @option{--extract}. If
you already know how to use some other version of @command{tar}, then you
may not need to read this chapter. This chapter omits most complicated
details about how @command{tar} works.
To understand how to run @command{tar} in the three operating modes listed
previously, you also need to understand how to use two of the options to
-@command{tar}: @samp{--file} (which takes an archive file as an argument)
-and @samp{--verbose}. (You are usually not @emph{required} to specify
+@command{tar}: @option{--file} (which takes an archive file as an argument)
+and @option{--verbose}. (You are usually not @emph{required} to specify
either of these options when you run @command{tar}, but they can be very
useful in making things more clear and helping you avoid errors.)
@end menu
@node file tutorial
-@unnumberedsubsec The @samp{--file} Option
+@unnumberedsubsec The @option{--file} Option
@table @kbd
@item --file=@var{archive-name}
@ref{file}.
@node verbose tutorial
-@unnumberedsubsec The @samp{--verbose} Option
+@unnumberedsubsec The @option{--verbose} Option
@table @kbd
@item --verbose
@value{op-verbose} shows details about the results of running
@command{tar}. This can be especially useful when the results might not be
obvious. For example, if you want to see the progress of @command{tar} as
-it writes files into the archive, you can use the @samp{--verbose}
+it writes files into the archive, you can use the @option{--verbose}
option. In the beginning, you may find it useful to use
-@samp{--verbose} at all times; when you are more accustomed to
+@option{--verbose} at all times; when you are more accustomed to
@command{tar}, you will likely want to use it at certain times but not at
-others. We will use @samp{--verbose} at times to help make something
+others. We will use @option{--verbose} at times to help make something
clear, and we will give many examples both using and not using
-@samp{--verbose} to show the differences.
+@option{--verbose} to show the differences.
-Sometimes, a single instance of @samp{--verbose} on the command line
+Sometimes, a single instance of @option{--verbose} on the command line
will show a full, @samp{ls} style listing of an archive or files,
@c FIXME: Describe the exact output format, e.g., how hard links are displayed.
giving sizes, owners, and similar information. Other times,
-@samp{--verbose} will only show files or members that the particular
+@option{--verbose} will only show files or members that the particular
operation is operating on at the time. In the latter case, you can
-use @samp{--verbose} twice in a command to get a listing such as that
+use @option{--verbose} twice in a command to get a listing such as that
in the former case. For example, instead of saying
@smallexample
@noindent
Note that you must double the hyphens properly each time.
-Later in the tutorial, we will give examples using @w{@samp{--verbose
+Later in the tutorial, we will give examples using @w{@option{--verbose
--verbose}}.
@node help tutorial
-@unnumberedsubsec Getting Help: Using the @code{--help} Option
+@unnumberedsubsec Getting Help: Using the @option{--help} Option
@table @kbd
@item --help
-The @samp{--help} option to @command{tar} prints out a very brief list of
+The @option{--help} option to @command{tar} prints out a very brief list of
all operations and option available for the current version of
@command{tar} available on your system.
@end table
One of the basic operations of @command{tar} is @value{op-create}, which
you use to create a @command{tar} archive. We will explain
-@samp{--create} first because, in order to learn about the other
+@option{--create} first because, in order to learn about the other
operations, you will find it useful to have an archive available to
practice on.
@file{blues}, @file{folk}, and @file{jazz}. The archive is called
@file{collection.tar}.
-This section will proceed slowly, detailing how to use @samp{--create}
+This section will proceed slowly, detailing how to use @option{--create}
in @code{verbose} mode, and showing examples using both short and long
forms. In the rest of the tutorial, and in the examples in the next
chapter, we will proceed at a slightly quicker pace. This section
into the habit of typing options in the order that makes inherent sense.
@xref{short create}, for more information on this.
-In this example, you type the command as shown above: @samp{--create}
+In this example, you type the command as shown above: @option{--create}
is the operation which creates the new archive
-(@file{collection.tar}), and @samp{--file} is the option which lets
+(@file{collection.tar}), and @option{--file} is the option which lets
you give it the name you chose. The files, @file{blues}, @file{folk},
and @file{jazz}, are now members of the archive, @file{collection.tar}
-(they are @dfn{file name arguments} to the @samp{--create} operation).
+(they are @dfn{file name arguments} to the @option{--create} operation).
@FIXME{xref here to the discussion of file name args?}Now that they are
in the archive, they are called @emph{archive members}, not files.
(@pxref{Definitions,members}).
Use @value{op-append} instead. @xref{append}.
@node create verbose
-@subsection Running @samp{--create} with @samp{--verbose}
+@subsection Running @option{--create} with @option{--verbose}
If you include the @value{op-verbose} option on the command line,
@command{tar} will list the files it is acting on as it is working. In
@end smallexample
This example is just like the example we showed which did not use
-@samp{--verbose}, except that @command{tar} generated the remaining lines
+@option{--verbose}, except that @command{tar} generated the remaining lines
@iftex
(note the different font styles).
@end iftex
@noindent
In this case, @command{tar} will make an archive file called @file{v},
containing the files @file{blues}, @file{folk}, and @file{jazz}, because
-the @samp{v} is the closest ``file name'' to the @samp{-f} option, and
+the @samp{v} is the closest ``file name'' to the @option{-f} option, and
is thus taken to be the chosen archive file name. @command{tar} will try
to add a file called @file{collection.tar} to the @file{v} archive file;
if the file @file{collection.tar} did not already exist, @command{tar} will
report an error indicating that this file does not exist. If the file
@file{collection.tar} does already exist (e.g., from a previous command
you may have run), then @command{tar} will add this file to the archive.
-Because the @samp{-v} option did not get registered, @command{tar} will not
+Because the @option{-v} option did not get registered, @command{tar} will not
run under @samp{verbose} mode, and will not report its progress.
The end result is that you may be quite confused about what happened,
@noindent
It would be very easy to put the wrong string of characters
-immediately following the @samp{-f}, but doing that could sacrifice
+immediately following the @option{-f}, but doing that could sacrifice
valuable data.
For this reason, we recommend that you pay very careful attention to
Be sure to use a @value{op-file} option just as with @value{op-create}
to specify the name of the archive.
-If you use the @value{op-verbose} option with @samp{--list}, then
+If you use the @value{op-verbose} option with @option{--list}, then
@command{tar} will print out a listing reminiscent of @w{@samp{ls -l}},
showing owner, file size, and so forth.
-rw-rw-rw- myself user 62 1990-05-23 10:55 folk
@end smallexample
-@cindex File name arguments, using @code{--list} with
-@cindex @code{--list} with file name arguments
+@cindex File name arguments, using @option{--list} with
+@cindex @option{--list} with file name arguments
You can specify one or more individual member names as arguments when
using @samp{list}. In this case, @command{tar} will only list the
names of members you identify. For example, @w{@kbd{tar --list
with @file{folk}, because @file{folk} is in the archive file
@file{collection.tar}. If you are not sure of the exact file name, try
listing all the files in the archive and searching for the one you
-expect to find; remember that if you use @samp{--list} with no file
+expect to find; remember that if you use @option{--list} with no file
names as arguments, @command{tar} will print the names of all the members
stored in the specified archive.
Extracting an archive does not modify the archive in any way; you can
extract it multiple times if you want or need to.
-Using @samp{--extract}, you can extract an entire archive, or specific
+Using @option{--extract}, you can extract an entire archive, or specific
files. The files can be directories containing other files, or not. As
with @value{op-create} and @value{op-list}, you may use the short or the
long form of the operation without affecting the performance.
name, and that directory does not exist under the working directory when
the file is extracted, @command{tar} will create the directory.
-We can demonstrate how to use @samp{--extract} to extract a directory
+We can demonstrate how to use @option{--extract} to extract a directory
file with an example. Change to the @file{practice} directory if you
weren't there, and remove the files @file{folk} and @file{jazz}. Then,
go back to the parent directory and extract the archive
can be used to specify an option containing whitespace or a backslash.
Note that @command{tar} options are case sensitive. For example, the
-options @samp{-T} and @samp{-t} are different; the first requires an
+options @option{-T} and @option{-t} are different; the first requires an
argument for stating the name of a file providing a list of @var{name}s,
while the second does not require an argument and is another way to
write @value{op-list}.
"mnemonic" with "long", or *ugh* vice versa.}
Each option has at least one long (or mnemonic) name starting with two
-dashes in a row, e.g.@: @samp{--list}. The long names are more clear than
+dashes in a row, e.g.@: @option{--list}. The long names are more clear than
their corresponding short or old names. It sometimes happens that a
single mnemonic option has many different different names which are
-synonymous, such as @samp{--compare} and @samp{--diff}. In addition,
+synonymous, such as @option{--compare} and @option{--diff}. In addition,
long option names can be given unique abbreviations. For example,
-@samp{--cre} can be used in place of @samp{--create} because there is no
+@option{--cre} can be used in place of @option{--create} because there is no
other mnemonic option which begins with @samp{cre}. (One way to find
this out is by trying it and seeing what happens; if a particular
abbreviation could represent more than one option, @command{tar} will tell
immediately following the option name. There are two ways of
specifying a mandatory argument. It can be separated from the
option name either by an equal sign, or by any amount of
-white space characters. For example, the @samp{--file} option (which
+white space characters. For example, the @option{--file} option (which
tells the name of the @command{tar} archive) is given a file such as
@file{archive.tar} as argument by using any of the following notations:
-@samp{--file=archive.tar} or @samp{--file archive.tar}.
+@option{--file=archive.tar} or @option{--file archive.tar}.
In contrast, optional arguments must always be introduced using
-an equal sign. For example, the @samp{--backup} option takes
+an equal sign. For example, the @option{--backup} option takes
an optional argument specifying backup type. It must be used
-as @samp{--backup=@var{backup-type}}.
+as @option{--backup=@var{backup-type}}.
@node Short Options
@subsection Short Option Style
Most options also have a short option name. Short options start with
-a single dash, and are followed by a single character, e.g.@: @samp{-t}
-(which is equivalent to @samp{--list}). The forms are absolutely
+a single dash, and are followed by a single character, e.g.@: @option{-t}
+(which is equivalent to @option{--list}). The forms are absolutely
identical in function; they are interchangeable.
The short option names are faster to type than long option names.
Short options which require arguments take their arguments immediately
following the option, usually separated by white space. It is also
possible to stick the argument right after the short option name, using
-no intervening space. For example, you might write @w{@samp{-f
-archive.tar}} or @samp{-farchive.tar} instead of using
-@samp{--file=archive.tar}. Both @samp{--file=@var{archive-name}} and
-@w{@samp{-f @var{archive-name}}} denote the option which indicates a
+no intervening space. For example, you might write @w{@option{-f
+archive.tar}} or @option{-farchive.tar} instead of using
+@option{--file=archive.tar}. Both @option{--file=@var{archive-name}} and
+@w{@option{-f @var{archive-name}}} denote the option which indicates a
specific archive, here named @file{archive.tar}.
Short options which take optional arguments take their arguments
@command{tar} program name and some white space; old options cannot appear
anywhere else. The letter of an old option is exactly the same letter as
the corresponding short option. For example, the old option @samp{t} is
-the same as the short option @samp{-t}, and consequently, the same as the
-mnemonic option @samp{--list}. So for example, the command @w{@samp{tar
-cv}} specifies the option @samp{-v} in addition to the operation @samp{-c}.
+the same as the short option @option{-t}, and consequently, the same as the
+mnemonic option @option{--list}. So for example, the command @w{@samp{tar
+cv}} specifies the option @option{-v} in addition to the operation @option{-c}.
@FIXME{bob suggests having an uglier example. :-) }
@end smallexample
@noindent
-Here, @samp{20} is the argument of @samp{-b} and @samp{/dev/rmt0} is
-the argument of @samp{-f}.
+Here, @samp{20} is the argument of @option{-b} and @samp{/dev/rmt0} is
+the argument of @option{-f}.
On the other hand, this old style syntax makes it difficult to match
option letters with their corresponding arguments, and is often
confusing. In the command @w{@samp{tar cvbf 20 /dev/rmt0}}, for example,
-@samp{20} is the argument for @samp{-b}, @samp{/dev/rmt0} is the
-argument for @samp{-f}, and @samp{-v} does not have a corresponding
+@samp{20} is the argument for @option{-b}, @samp{/dev/rmt0} is the
+argument for @option{-f}, and @option{-v} does not have a corresponding
argument. Even using short options like in @w{@samp{tar -c -v -b 20 -f
/dev/rmt0}} is clearer, putting all arguments next to the option they
pertain to.
user intended (judging based on the example in the previous set which
uses long options, whose intent is therefore very clear). The first
four specify that the @command{tar} archive would be a file named
-@samp{-c}, @samp{c}, @samp{carchive.tar} or @samp{archive.tarc},
+@option{-c}, @samp{c}, @samp{carchive.tar} or @samp{archive.tarc},
respectively. The first two examples also specify a single non-option,
@var{name} argument having the value @samp{archive.tar}. The last
example contains only old style option letters (repeating option
@item --catenate
@itemx -A
-Same as @samp{--concatenate}. @xref{concatenate}.
+Same as @option{--concatenate}. @xref{concatenate}.
@item --compare
@itemx -d
@item --diff
@itemx -d
-Same @samp{--compare}. @xref{compare}.
+Same @option{--compare}. @xref{compare}.
@item --extract
@itemx -x
@item --get
@itemx -x
-Same as @samp{--extract}. @xref{extract}.
+Same as @option{--extract}. @xref{extract}.
@item --list
@itemx -t
@item --update
@itemx -u
-@FIXME{It was: A combination of the @samp{--compare} and
-@samp{--append} operations. This is not true and rather misleading,
+@FIXME{It was: A combination of the @option{--compare} and
+@option{--append} operations. This is not true and rather misleading,
as @value{op-compare} does a lot more than @value{op-update} for
ensuring files are identical.} Adds files to the end of the archive,
but only if they are newer than their counterparts already in the
@item --after-date
-(See @samp{--newer}.) @FIXME-pxref{}
+(See @option{--newer}.) @FIXME-pxref{}
@item --anchored
An exclude pattern must match an initial subsequence of the name's components.
This option directs @command{tar} to print periodic checkpoint messages as it
reads through the archive. Its intended for when you want a visual
indication that @command{tar} is still running, but don't want to see
-@samp{--verbose} output. @FIXME-xref{}
+@option{--verbose} output. @FIXME-xref{}
@item --check-links
@itemx -l
@item --confirmation
-(See @samp{--interactive}.) @FIXME-pxref{}
+(See @option{--interactive}.) @FIXME-pxref{}
@item --dereference
@itemx -h
@item --exclude-from=@var{file}
@itemx -X @var{file}
-Similar to @samp{--exclude}, except @command{tar} will use the list of
+Similar to @option{--exclude}, except @command{tar} will use the list of
patterns in the file @var{file}. @FIXME-xref{}
+@item --exclude-caches
+
+Automatically excludes all directories
+containing a cache directory tag. @FIXME-xref{}
+
@item --file=@var{archive}
@itemx -f @var{archive}
@item --force-local
-Forces @command{tar} to interpret the filename given to @samp{--file}
+Forces @command{tar} to interpret the filename given to @option{--file}
as a local file, even if it looks like a remote tape drive name.
@FIXME-xref{}
@item --listed-incremental=@var{snapshot-file}
@itemx -g @var{snapshot-file}
-During a @samp{--create} operation, specifies that the archive that
+During a @option{--create} operation, specifies that the archive that
@command{tar} creates is a new @acronym{GNU}-format incremental
backup, using @var{snapshot-file} to determine which files to backup.
With other operations, informs @command{tar} that the archive is in
@item --newer-mtime=@var{date}
-Like @samp{--newer}, but add only files whose
-contents have changed (as opposed to just @samp{--newer}, which will
+Like @option{--newer}, but add only files whose
+contents have changed (as opposed to just @option{--newer}, which will
also back up files for which any status information has changed).
@item --no-anchored
When extracting an archive, do not attempt to preserve the owner
specified in the @command{tar} archive. This the default behavior
-for ordinary users; this option has an effect only for the superuser.
+for ordinary users.
@item --no-same-permissions
When extracting an archive, subtract the user's umask from files from
the permissions specified in the archive. This is the default behavior
-for ordinary users; this option has an effect only for the superuser.
+for ordinary users.
@item --no-wildcards
Do not use wildcards when excluding files.
@item --null
-When @command{tar} is using the @samp{--files-from} option, this option
+When @command{tar} is using the @option{--files-from} option, this option
instructs @command{tar} to expect filenames terminated with @kbd{NUL}, so
@command{tar} can correctly work with file names that contain newlines.
@FIXME-xref{}
@item --preserve
-Synonymous with specifying both @samp{--preserve-permissions} and
-@samp{--same-order}. @FIXME-xref{}
+Synonymous with specifying both @option{--preserve-permissions} and
+@option{--same-order}. @FIXME-xref{}
@item --preserve-order
-(See @samp{--same-order}; @pxref{Reading}.)
+(See @option{--same-order}; @pxref{Reading}.)
@item --preserve-permissions
@itemx --same-permissions
@item --same-permissions
-(See @samp{--preserve-permissions}; @pxref{Writing}.)
+(See @option{--preserve-permissions}; @pxref{Writing}.)
@item --show-defaults
@item --uncompress
-(See @samp{--compress}.) @FIXME-pxref{}
+(See @option{--compress}.) @FIXME-pxref{}
@item --ungzip
-(See @samp{--gzip}.) @FIXME-pxref{}
+(See @option{--gzip}.) @FIXME-pxref{}
@item --unlink-first
@itemx -U
@item --utc
Display file modification dates in @acronym{UTC}. This option implies
-@samp{--verbose}.
+@option{--verbose}.
@item --verbose
@itemx -v
@item --volno-file=@var{file}
-Used in conjunction with @samp{--multi-volume}. @command{tar} will keep track
+Used in conjunction with @option{--multi-volume}. @command{tar} will keep track
of which volume of a multi-volume archive its working in @var{file}.
@FIXME-xref{}
@item -A
-@samp{--concatenate}
+@option{--concatenate}
@item -B
-@samp{--read-full-records}
+@option{--read-full-records}
@item -C
-@samp{--directory}
+@option{--directory}
@item -F
-@samp{--info-script}
+@option{--info-script}
@item -G
-@samp{--incremental}
+@option{--incremental}
@item -K
-@samp{--starting-file}
+@option{--starting-file}
@item -L
-@samp{--tape-length}
+@option{--tape-length}
@item -M
-@samp{--multi-volume}
+@option{--multi-volume}
@item -N
-@samp{--newer}
+@option{--newer}
@item -O
-@samp{--to-stdout}
+@option{--to-stdout}
@item -P
-@samp{--absolute-names}
+@option{--absolute-names}
@item -R
-@samp{--block-number}
+@option{--block-number}
@item -S
-@samp{--sparse}
+@option{--sparse}
@item -T
-@samp{--files-from}
+@option{--files-from}
@item -U
-@samp{--unlink-first}
+@option{--unlink-first}
@item -V
-@samp{--label}
+@option{--label}
@item -W
-@samp{--verify}
+@option{--verify}
@item -X
-@samp{--exclude-from}
+@option{--exclude-from}
@item -Z
-@samp{--compress}
+@option{--compress}
@item -b
-@samp{--blocking-factor}
+@option{--blocking-factor}
@item -c
-@samp{--create}
+@option{--create}
@item -d
-@samp{--compare}
+@option{--compare}
@item -f
-@samp{--file}
+@option{--file}
@item -g
-@samp{--listed-incremental}
+@option{--listed-incremental}
@item -h
-@samp{--dereference}
+@option{--dereference}
@item -i
-@samp{--ignore-zeros}
+@option{--ignore-zeros}
@item -j
-@samp{--bzip2}
+@option{--bzip2}
@item -k
-@samp{--keep-old-files}
+@option{--keep-old-files}
@item -l
-@samp{--one-file-system}. Use of this short option is deprecated. It
+@option{--one-file-system}. Use of this short option is deprecated. It
is retained for compatibility with the earlier versions of GNU
@command{tar}, and will be changed in future releases.
@item -m
-@samp{--touch}
+@option{--touch}
@item -o
-When creating --- @samp{--no-same-owner}, when extracting ---
-@samp{--portability}.
+When creating --- @option{--no-same-owner}, when extracting ---
+@option{--portability}.
The later usage is deprecated. It is retained for compatibility with
the earlier versions of @GNUTAR{}. In the future releases
-@option{-o} will be equivalent to @samp{--no-same-owner} only.
+@option{-o} will be equivalent to @option{--no-same-owner} only.
@item -p
-@samp{--preserve-permissions}
+@option{--preserve-permissions}
@item -r
-@samp{--append}
+@option{--append}
@item -s
-@samp{--same-order}
+@option{--same-order}
@item -t
-@samp{--list}
+@option{--list}
@item -u
-@samp{--update}
+@option{--update}
@item -v
-@samp{--verbose}
+@option{--verbose}
@item -w
-@samp{--interactive}
+@option{--interactive}
@item -x
-@samp{--extract}
+@option{--extract}
@item -z
-@samp{--gzip}
+@option{--gzip}
@end table
if disk or storage space is tight). You can do this by excluding
certain files automatically (@pxref{Choosing}), or by performing
an operation interactively, using the @value{op-interactive} option.
-@command{tar} also accepts @samp{--confirmation} for this option.
+@command{tar} also accepts @option{--confirmation} for this option.
When the @value{op-interactive} option is specified, before
reading, writing, or deleting files, @command{tar} first prints a message
In the last chapter, you learned about the first three operations to
@command{tar}. This chapter presents the remaining five operations to
-@command{tar}: @samp{--append}, @samp{--update}, @samp{--concatenate},
-@samp{--delete}, and @samp{--compare}.
+@command{tar}: @option{--append}, @option{--update}, @option{--concatenate},
+@option{--delete}, and @option{--compare}.
You are not likely to use these operations as frequently as those
covered in the last chapter; however, since they perform specialized
@end table
@node append
-@subsection How to Add Files to Existing Archives: @code{--append}
+@subsection How to Add Files to Existing Archives: @option{--append}
@UNREVISED
If you want to add files to an existing archive, you don't need to
create a new archive; you can use @value{op-append}. The archive must
-already exist in order to use @samp{--append}. (A related operation
-is the @samp{--update} operation; you can use this to add newer
+already exist in order to use @option{--append}. (A related operation
+is the @option{--update} operation; you can use this to add newer
versions of archive members to an existing archive. To learn how to
-do this with @samp{--update}, @pxref{update}.)
+do this with @option{--update}, @pxref{update}.)
If you use @value{op-append} to add a file that has the same name as an
archive member to an archive containing that archive member, then the
prefer; if you were to use @value{op-extract} to extract the archive,
only the most recently added copy of a member with the same name as four
other members would end up in the working directory. This is because
-@samp{--extract} extracts an archive in the order the members appeared
+@option{--extract} extracts an archive in the order the members appeared
in the archive; the most recently archived members will be extracted
last. Additionally, an extracted member will @emph{replace} a file of
the same name which existed in the directory already, and @command{tar}
@cindex Replacing members with other members
If you want to replace an archive member, use @value{op-delete} to
delete the member you want to remove from the archive, , and then use
-@samp{--append} to add the member you want to be in the archive. Note
+@option{--append} to add the member you want to be in the archive. Note
that you can not change the order of the archive; the most recently
added member will still appear last. In this sense, you cannot truly
``replace'' one member with another. (Replacing one member with another
The simplest way to add a file to an already existing archive is the
@value{op-append} operation, which writes specified files into the
archive whether or not they are already among the archived files.
-When you use @samp{--append}, you @emph{must} specify file name
+When you use @option{--append}, you @emph{must} specify file name
arguments, as there is no default. If you specify a file that already
exists in the archive, another copy of the file will be added to the
end of the archive. As with other operations, the member names of the
command line. The @value{op-verbose} option will print out the names
of the files as they are written into the archive.
-@samp{--append} cannot be performed on some tape drives, unfortunately,
+@option{--append} cannot be performed on some tape drives, unfortunately,
due to deficiencies in the formats those tape drives use. The archive
must be a valid @command{tar} archive, or else the results of using this
operation will be unpredictable. @xref{Media}.
-To demonstrate using @samp{--append} to add a file to an archive,
+To demonstrate using @option{--append} to add a file to an archive,
create a file called @file{rock} in the @file{practice} directory.
Make sure you are in the @file{practice} directory. Then, run the
following @command{tar} command to add @file{rock} to
You can use @value{op-append} to add copies of files which have been
updated since the archive was created. (However, we do not recommend
doing this since there is another @command{tar} option called
-@samp{--update}; @pxref{update} for more information. We describe this
-use of @samp{--append} here for the sake of completeness.) @FIXME{is
+@option{--update}; @pxref{update} for more information. We describe this
+use of @option{--append} here for the sake of completeness.) @FIXME{is
this really a good idea, to give this whole description for something
which i believe is basically a Stupid way of doing something? certain
aspects of it show ways in which tar is more broken than i'd personally
@end smallexample
@noindent
-Because you specified the @samp{--verbose} option, @command{tar} has
+Because you specified the @option{--verbose} option, @command{tar} has
printed the name of the file being appended as it was acted on. Now
list the contents of the archive:
In the previous section, you learned how to use @value{op-append} to add
a file to an existing archive. A related operation is
-@value{op-update}. The @samp{--update} operation updates a @command{tar}
+@value{op-update}. The @option{--update} operation updates a @command{tar}
archive by comparing the date of the specified archive members against
the date of the file with the same name. If the file has been modified
more recently than the archive member, then the newer version of the
file is added to the archive (as with @value{op-append}).
-Unfortunately, you cannot use @samp{--update} with magnetic tape drives.
+Unfortunately, you cannot use @option{--update} with magnetic tape drives.
The operation will fail.
@FIXME{other examples of media on which --update will fail? need to ask
charles and/or mib/thomas/dave shevett..}
-Both @samp{--update} and @samp{--append} work by adding to the end
+Both @option{--update} and @option{--append} work by adding to the end
of the archive. When you extract a file from the archive, only the
version stored last will wind up in the file system, unless you use
the @value{op-backup} option. @FIXME-ref{Multiple Members with the
@end menu
@node how to update
-@subsubsection How to Update an Archive Using @code{--update}
+@subsubsection How to Update an Archive Using @option{--update}
You must use file name arguments with the @value{op-update} operation.
If you don't specify any files, @command{tar} won't act on any files and
@FIXME{note: the above parenthetical added because in fact, this
behavior just confused the author. :-) }
-To see the @samp{--update} option at work, create a new file,
+To see the @option{--update} option at work, create a new file,
@file{classical}, in your practice directory, and some extra text to the
file @file{blues}, using any text editor. Then invoke @command{tar} with
the @samp{update} operation and the @value{op-verbose} option specified,
efficient. If you need to run backups, please consult @ref{Backups}.
@node concatenate
-@subsection Combining Archives with @code{--concatenate}
+@subsection Combining Archives with @option{--concatenate}
@cindex Adding archives to an archive
@cindex Concatenating Archives
one or more archives to the end of another archive, you should use the
@value{op-concatenate} operation.
-To use @samp{--concatenate}, name the archives to be concatenated on the
+To use @option{--concatenate}, name the archives to be concatenated on the
command line. (Nothing happens if you don't list any.) The members,
and their member names, will be copied verbatim from those archives. If
this causes multiple members to have the same name, it does not delete
information on how this affects reading the archive, Multiple
Members with the Same Name.}
-To demonstrate how @samp{--concatenate} works, create two small archives
+To demonstrate how @option{--concatenate} works, create two small archives
called @file{bluesrock.tar} and @file{folkjazz.tar}, using the relevant
files from @file{practice}:
folk
@end smallexample
-When you use @samp{--concatenate}, the source and target archives must
+When you use @option{--concatenate}, the source and target archives must
already exist and must have been created using compatible format
parameters. @FIXME-pxref{Matching Format Parameters}The new,
concatenated archive will be called by the same name as the first
@cindex @code{concatenate} vs @command{cat}
@cindex @command{cat} vs @code{concatenate}
It may seem more intuitive to you to want or try to use @command{cat} to
-concatenate two archives instead of using the @samp{--concatenate}
+concatenate two archives instead of using the @option{--concatenate}
operation; after all, @command{cat} is the utility for combining files.
However, @command{tar} archives incorporate an end-of-file marker which
must be removed if the concatenated archives are to be read properly as
-one archive. @samp{--concatenate} removes the end-of-archive marker
+one archive. @option{--concatenate} removes the end-of-archive marker
from the target archive before each new archive is appended. If you use
@command{cat} to combine the archives, the result will not be a valid
@command{tar} format archive. If you need to retrieve files from an
default archive name.
@node delete
-@subsection Removing Archive Members Using @samp{--delete}
+@subsection Removing Archive Members Using @option{--delete}
@UNREVISED
@cindex Deleting files from an archive
@cindex Removing files from an archive
names, nothing will be deleted. The @value{op-verbose} option will
cause @command{tar} to print the names of the members as they are deleted.
As with @value{op-extract}, you must give the exact member names when
-using @samp{tar --delete}. @samp{--delete} will remove all versions of
-the named file from the archive. The @samp{--delete} operation can run
+using @samp{tar --delete}. @option{--delete} will remove all versions of
+the named file from the archive. The @option{--delete} operation can run
very slowly.
-Unlike other operations, @samp{--delete} has no short form.
+Unlike other operations, @option{--delete} has no short form.
-@cindex Tapes, using @code{--delete} and
+@cindex Tapes, using @option{--delete} and
@cindex Deleting from tape archives
This operation will rewrite the archive. You can only use
-@samp{--delete} on an archive if the archive device allows you to
+@option{--delete} on an archive if the archive device allows you to
write to any point on the media, such as a disk; because of this, it
does not work on magnetic tapes. Do not try to delete an archive member
from a magnetic tape; the action will not succeed, and you will be
@cindex Verifying the currency of an archive
@UNREVISED
-The @samp{--compare} (@samp{-d}), or @samp{--diff} operation compares
+The @option{--compare} (@option{-d}), or @option{--diff} operation compares
specified archive members against files with the same names, and then
reports differences in file size, mode, owner, modification date and
contents. You should @emph{only} specify archive member names, not file
the integrity of the archive media. For this later goal, @xref{verify}.
@node create options
-@section Options Used by @code{--create}
+@section Options Used by @option{--create}
The previous chapter described the basics of how to use
@value{op-create} to create an archive from a set of files.
@xref{create}. This section described advanced options to be used with
-@samp{--create}.
+@option{--create}.
@menu
* Ignore Failed Read::
@end table
@node extract options
-@section Options Used by @code{--extract}
+@section Options Used by @option{--extract}
@UNREVISED
@FIXME{i need to get dan to go over these options with me and see if
an archive into the filesystem. Various options cause @command{tar} to
extract more information than just file contents, such as the owner,
the permissions, the modification date, and so forth. This section
-presents options to be used with @samp{--extract} when certain special
+presents options to be used with @option{--extract} when certain special
considerations arise. You may review the information presented in
@ref{extract} for more basic information about the
-@samp{--extract} operation.
+@option{--extract} operation.
@menu
* Reading:: Options to Help Read Archives
@unnumberedsubsubsec Setting Access Permissions
To set the modes (access permissions) of extracted files to those
-recorded for those files in the archive, use @samp{--same-permissions}
+recorded for those files in the archive, use @option{--same-permissions}
in conjunction with the @value{op-extract} operation. @FIXME{Should be
aliased to ignore-umask.}
@opindex --suffix
@cindex backup suffix
@vindex SIMPLE_BACKUP_SUFFIX
-Append @var{suffix} to each backup file made with @samp{--backup}. If this
+Append @var{suffix} to each backup file made with @option{--backup}. If this
option is not specified, the value of the @env{SIMPLE_BACKUP_SUFFIX}
environment variable is used. And if @env{SIMPLE_BACKUP_SUFFIX} is not
set, the default is @samp{~}, just as in Emacs.
Incremental dumps depend crucially on time stamps, so the results are
unreliable if you modify a file's time stamps during dumping (e.g.@:
-with the @samp{--atime-preserve} option), or if you set the clock
+with the @option{--atime-preserve} option), or if you set the clock
backwards.
Despite it should be obvious that a device has a non-volatile value, NFS
to be a better way to go.
@command{tar} doesn't access @var{snapshot-file} when
-@value{op-create} or @value{op-list} are specified, but the
+@value{op-extract} or @value{op-list} are specified, but the
@value{op-listed-incremental} option must still be given. A
placeholder @var{snapshot-file} can be specified, e.g.,
@file{/dev/null}.
@noindent
@file{collection.tar} is the name of the archive. It must directly
-follow the @samp{-f} option, since whatever directly follows @samp{-f}
+follow the @option{-f} option, since whatever directly follows @option{-f}
@emph{will} end up naming the archive. If you neglect to specify an
archive name, you may end up overwriting a file in the working directory
with the archive you create since @command{tar} will use this file's name
@noindent
@command{tar} will complete the remote connection, if possible, and
prompt you for a username and password. If you use
-@samp{--file=@@@var{hostname}:/@var{dev}/@var{file name}}, @command{tar}
+@option{--file=@@@var{hostname}:/@var{dev}/@var{file name}}, @command{tar}
will complete the remote connection, if possible, using your username
as the username on the remote machine.
@kbd{tar} @var{operation} [@var{option1} @var{option2} @dots{}] [@var{file name-1} @var{file name-2} @dots{}]
@end smallexample
+If a file name begins with dash (@samp{-}), preceede it with
+@option{--add-file} option to preventit from being treated as an
+option.
+
If you specify a directory name as a file name argument, all the files
in that directory are operated on by @command{tar}.
@node files
@section Reading Names from a File
-@UNREVISED
@cindex Reading file names from a file
@cindex Lists of file names
line, you can put the names into a file, and then use the
@value{op-files-from} option to @command{tar}. Give the name of the file
which contains the list of files to include as the argument to
-@samp{--files-from}. In the list, the file names should be separated by
-newlines. You will frequently use this option when you have generated
+@option{--files-from}. In the list, the file names should be separated by
+newlines. You will frequently use this option when you have generated
the list of files to archive with the @command{find} utility.
@table @kbd
Get names to extract or create from file @var{file name}.
@end table
-If you give a single dash as a file name for @samp{--files-from}, (i.e.,
-you specify either @samp{--files-from=-} or @samp{-T -}), then the file
+If you give a single dash as a file name for @option{--files-from}, (i.e.,
+you specify either @code{--files-from=-} or @code{-T -}), then the file
names are read from standard input.
-Unless you are running @command{tar} with @samp{--create}, you can not use
-both @samp{--files-from=-} and @samp{--file=-} (@samp{-f -}) in the same
+Unless you are running @command{tar} with @option{--create}, you can not use
+both @code{--files-from=-} and @code{--file=-} (@code{-f -}) in the same
command.
+Any number of @option{-T} options can be given in the command line.
+
@FIXME{add bob's example, from his message on 2-10-97}
The following example shows how to use @command{find} to generate a list of
files smaller than 400K in length and put that list into a file
-called @file{small-files}. You can then use the @samp{-T} option to
+called @file{small-files}. You can then use the @option{-T} option to
@command{tar} to specify the files from that file, @file{small-files}, to
-create the archive @file{little.tgz}. (The @samp{-z} option to
+create the archive @file{little.tgz}. (The @option{-z} option to
@command{tar} compresses the archive with @command{gzip}; @pxref{gzip} for
more information.)
@end smallexample
@noindent
-@FIXME{say more here to conclude the example/section?}
+In the file list given by @option{-T} option, any file name beginning
+with @samp{-} character is considered a @command{tar} option and is
+processed accordingly.@footnote{Versions of @GNUTAR{} up to 1.15.1
+recognized only @option{-C} option in file lists, and only if the
+option and its argument occupied two consecutive lines.} For example,
+the common use of this feature is to change to another directory by
+specifying @option{-C} option:
+
+@smallexample
+@group
+$ @kbd{cat list}
+-C/etc
+passwd
+hosts
+-C/lib
+libc.a
+$ @kbd{tar -c -f foo.tar --files-from list}
+@end group
+@end smallexample
+
+@noindent
+In this example, @command{tar} will first switch to @file{/etc}
+directory and add files @file{passwd} and @file{hosts} to the
+archive. Then it will change to @file{/lib} directory and will archive
+the file @file{libc.a}. Thus, the resulting archive @file{foo.tar} will
+contain:
+
+@smallexample
+@group
+$ @kbd{tar tf foo.tar}
+passwd
+hosts
+libc.a
+@end group
+@end smallexample
+
+@noindent
+Notice that the option parsing algorithm used with @option{-T} is
+stricter than the one used by shell. Namely, when specifying option
+arguments, you should observe the following rules:
+
+@itemize @bullet
+@item
+When using short (single-letter) option form, its argument must
+immediately follow the option letter, without any intervening
+whitespace. For example: @code{-Cdir}.
+
+@item
+When using long option form, the option argument must be separated
+from the option by a single equal sign. No whitespace is allowed on
+any side of the equal sign. For example: @code{--directory=dir}.
+
+@item
+For both short and long option forms, the option argument can be given
+on the next line after the option name, e.g.:
+
+@smallexample
+@group
+--directory
+dir
+@end group
+@end smallexample
+
+@noindent
+and
+
+@smallexample
+@group
+-C
+dir
+@end group
+@end smallexample
+@end itemize
+
+@cindex @option{--add-file}
+If you happen to have a file whose name starts with @samp{-},
+precede it with @option{--add-file} option to prevent it from
+being recognized as an option. For example: @code{--add-file --my-file}.
@menu
* nul::
@cindex @kbd{NUL} terminated file names
The @value{op-null} option causes @value{op-files-from} to read file
names terminated by a @code{NUL} instead of a newline, so files whose
-names contain newlines can be archived using @samp{--files-from}.
+names contain newlines can be archived using @option{--files-from}.
@table @kbd
@item --null
terminate in a newline.
@end table
-The @samp{--null} option is just like the one in @acronym{GNU}
+The @value{op-null} option is just like the one in @acronym{GNU}
@command{xargs} and @command{cpio}, and is useful with the
-@samp{-print0} predicate of @acronym{GNU} @command{find}. In
-@command{tar}, @samp{--null} also causes @value{op-directory} options
-to be treated as file names to archive, in case there are any files
-out there called @file{-C}.
+@option{-print0} predicate of @acronym{GNU} @command{find}. In
+@command{tar}, @value{op-null} also disables special handling for
+file names that begin with dash.
This example shows how to use @command{find} to generate a list of files
larger than 800K in length and put that list into a file called
-@file{long-files}. The @samp{-print0} option to @command{find} just just
-like @samp{-print}, except that it separates files with a @kbd{NUL}
+@file{long-files}. The @option{-print0} option to @command{find} is just
+like @option{-print}, except that it separates files with a @kbd{NUL}
rather than with a newline. You can then run @command{tar} with both the
-@samp{--null} and @samp{-T} options to specify that @command{tar} get the
+@option{--null} and @option{-T} options to specify that @command{tar} get the
files from that file, @file{long-files}, to create the archive
-@file{big.tgz}. The @samp{--null} option to @command{tar} will cause
+@file{big.tgz}. The @option{--null} option to @command{tar} will cause
@command{tar} to recognize the @kbd{NUL} separator between files.
@smallexample
@file{src} except for files whose names end in @file{.o}, use the
command @samp{tar -cf src.tar --exclude='*.o' src}.
-You may give multiple @samp{--exclude} options.
+You may give multiple @option{--exclude} options.
@table @kbd
@item --exclude-from=@var{file}
@end table
@findex exclude-from
-Use the @samp{--exclude-from=@var{file-of-patterns}} option to read a
+Use the @option{--exclude-from=@var{file-of-patterns}} option to read a
list of patterns, one per line, from @var{file}; @command{tar} will
ignore files matching those patterns. Thus if @command{tar} is
called as @w{@samp{tar -c -X foo .}} and the file @file{foo} contains a
@FIXME{do the exclude options files need to have stuff separated by
newlines the same as the files-from option does?}
+@table @kbd
+@item --exclude-caches
+Causes @command{tar} to ignore directories containing a cache directory tag.
+@end table
+
+@findex exclude-caches
+When creating an archive,
+the @option{--exclude-caches} option
+causes @command{tar} to exclude all directories
+that contain a @dfn{cache directory tag}.
+A cache directory tag is a short file
+with the well-known name @file{CACHEDIR.TAG}
+and having a standard header
+specified in @url{http://www.brynosaurus.com/cachedir/spec.html}.
+Various applications write cache directory tags
+into directories they use to hold regenerable, non-precious data,
+so that such data can be more easily excluded from backups.
+
@menu
* controlling pattern-patching with exclude::
* problems with exclude::
You can sometimes confuse the meanings of @value{op-exclude} and
@value{op-exclude-from}. Be careful: use @value{op-exclude} when files
to be excluded are given as a pattern on the command line. Use
-@samp{--exclude-from=@var{file-of-patterns}} to introduce the name of a
+@option{--exclude-from=@var{file-of-patterns}} to introduce the name of a
file which contains a list of patterns, one per line; each of these
patterns can exclude zero, one, or many files.
@item
In earlier versions of @command{tar}, what is now the
-@samp{--exclude-from=@var{file-of-patterns}} option was called
-@samp{--exclude=@var{pattern}} instead. Now,
-@samp{--exclude=@var{pattern}} applies to patterns listed on the command
-line and @samp{--exclude-from=@var{file-of-patterns}} applies to
+@option{--exclude-from=@var{file-of-patterns}} option was called
+@option{--exclude=@var{pattern}} instead. Now,
+@option{--exclude=@var{pattern}} applies to patterns listed on the command
+line and @option{--exclude-from=@var{file-of-patterns}} applies to
patterns listed in a file.
@end itemize
given. If @var{date} starts with @samp{/} or @samp{.}, it is taken to
be a file name; the last-modified time of that file is used as the date.
If you use this option when creating or appending to an archive,
-the archive will only include new files. If you use @samp{--after-date}
+the archive will only include new files. If you use @option{--after-date}
when extracting an archive, @command{tar} will only extract files newer
than the @var{date} you specify.
want @command{tar} to act this way.
The @value{op-no-recursion} option inhibits @command{tar}'s recursive descent
-into specified directories. If you specify @samp{--no-recursion}, you can
+into specified directories. If you specify @option{--no-recursion}, you can
use the @command{find} utility for hunting through levels of directories to
construct a list of file names which you could then pass to @command{tar}.
@command{find} allows you to be more selective when choosing which files to
This is the default.
@end table
-When you use @samp{--no-recursion}, @GNUTAR{} grabs
+When you use @option{--no-recursion}, @GNUTAR{} grabs
directory entries themselves, but does not descend on them
recursively. Many people use @command{find} for locating files they
want to back up, and since @command{tar} @emph{usually} recursively
archiving. Use in conjunction with any write operation.
@end table
-The @samp{--one-file-system} option causes @command{tar} to modify its
+The @option{--one-file-system} option causes @command{tar} to modify its
normal behavior in archiving the contents of directories. If a file in
a directory is not on the same filesystem as the directory itself, then
@command{tar} will not archive that file. If the file is a directory
@samp{tar --extract}, the third file will be written in a subdirectory
named @file{orange-colored}.
-You can use the @samp{--directory} option to make the archive
+You can use the @option{--directory} option to make the archive
independent of the original name of the directory holding the files.
The following command places the files @file{/etc/passwd},
@file{/etc/hosts}, and @file{/lib/libc.a} into the archive
They will not appear to be related by file name to the original
directories where those files were located.
-Note that @samp{--directory} options are interpreted consecutively. If
-@samp{--directory} specifies a relative file name, it is interpreted
+Note that @option{--directory} options are interpreted consecutively. If
+@option{--directory} specifies a relative file name, it is interpreted
relative to the then current directory, which might not be the same as
the original current working directory of @command{tar}, due to a previous
-@samp{--directory} option.
+@option{--directory} option.
+
+When using @option{--files-from} (@pxref{files}), you can put various
+@command{tar} options (including @option{-C}) in the file list. Notice,
+however, that in this case the option and its argument may not be
+separated by whitespace. If you use short option, its argument must
+either follow the option letter immediately, without any intervening
+whitespace, or occupy the next line. Otherwise, if you use long
+option, separate its argument by an equal sign.
-When using @samp{--files-from} (@pxref{files}), you can put @samp{-C}
-options in the file list. Notice, however, that in this case the
-option and its argument must occupy two consecutive lines. For
-instance, the file list for the above example will be:
+For instance, the file list for the above example will be:
@smallexample
@group
archive in V7 format (not ANSI), which can be read by these old
versions, specify the @value{op-format-v7} option in
conjunction with the @value{op-create} (@command{tar} also
-accepts @samp{--portability} or @samp{op-old-archive} for this
+accepts @option{--portability} or @samp{op-old-archive} for this
option). When you specify it,
@command{tar} leaves out information about directories, pipes, fifos,
contiguous files, and device files, and specifies file ownership by
@subsection Creating and Reading Compressed Archives
@cindex Compressed archives
@cindex Storing archives in compressed format
-@UNREVISED
+
+@GNUTAR{} is able to create and read compressed archives. It supports
+@command{gzip} and @command{bzip2} compression programms. For backward
+compatibilty, it also supports @command{compress} command, although
+we strongly recommend against using it, since there is a patent
+covering the algorithm it uses and you could be sued for patent
+infringement merely by running @command{compress}! Besides, it is less
+effective than @command{gzip} and @command{bzip2}.
+
+Creating a compressed archive is simple: you just specify a
+@dfn{compression option} along with the usual archive creation
+commands. The compression option is @option{-z} (@option{--gzip}) to
+create a @command{gzip} compressed archive, @option{-j}
+(@option{--bzip2}) to create a @command{bzip2} compressed archive, and
+@option{-Z} (@option{--compress}) to use @command{compress} program.
+For example:
+
+@smallexample
+$ @kbd{tar cfz archive.tar.gz .}
+@end smallexample
+
+Reading compressed archive is even simpler: you don't need to specify
+any additional options as @GNUTAR{} recognizes its format
+automatically. Thus, the following commands will list and extract the
+archive created in previous example:
+
+@smallexample
+# List the compressed archive
+$ @kbd{tar tf archive.tar.gz}
+# Extract the compressed archive
+$ @kbd{tar xf archive.tar.gz}
+@end smallexample
+
+The only case when you have to specify a decompression option while
+reading the archive is when reading from a pipe or from a tape drive
+that does not support random access. However, in this case @GNUTAR{}
+will indicate which option you should use. For example:
+
+@smallexample
+$ @kbd{cat archive.tar.gz | tar tf -}
+tar: Archive is compressed. Use -z option
+tar: Error is not recoverable: exiting now
+@end smallexample
+
+If you see such diagnostics, just add the suggested option to the
+invocation of @GNUTAR{}:
+
+@smallexample
+$ @kbd{cat archive.tar.gz | tar tfz -}
+@end smallexample
+
+Notice also, that there are several restrictions on operations on
+compressed archives. First of all, compressed archives cannot be
+modified, i.e. you cannot update (@value{op-update}) them or delete
+(@value{op-delete}) members from them. Likewise, you cannot append
+another @command{tar} archive to a compressed archive using
+@value{op-append}). Secondly, multi-volume archives cannot be
+compressed.
+
+The following table summarizes compression options used by @GNUTAR{}.
@table @kbd
@item -z
@itemx --gzip
@itemx --ungzip
Filter the archive through @command{gzip}.
-@end table
-
-@FIXME{ach; these two bits orig from "compare" (?). where to put?} Some
-format parameters must be taken into consideration when modifying an
-archive.@FIXME{???} Compressed archives cannot be modified.
-You can use @samp{--gzip} and @samp{--gunzip} on physical devices
+You can use @option{--gzip} and @option{--gunzip} on physical devices
(tape drives, etc.) and remote files as well as on normal files; data
to or from such devices or remote files is reblocked by another copy
of the @command{tar} program to enforce the specified (or default) record
size. The default compression parameters are used; if you need to
-override them, avoid the @value{op-gzip} option and run @command{gzip}
-explicitly. (Or set the @env{GZIP} environment variable.)
-
-The @value{op-gzip} option does not work with the @value{op-multi-volume}
-option, or with the @value{op-update}, @value{op-append},
-@value{op-concatenate}, or @value{op-delete} operations.
-
-It is not exact to say that @GNUTAR{} is to work in concert
-with @command{gzip} in a way similar to @command{zip}, say. Surely, it is
-possible that @command{tar} and @command{gzip} be done with a single call,
-like in:
-
-@smallexample
-$ @kbd{tar cfz archive.tar.gz subdir}
-@end smallexample
-
-@noindent
-to save all of @samp{subdir} into a @code{gzip}'ed archive. Later you
-can do:
+override them, set @env{GZIP} environment variable, e.g.:
@smallexample
-$ @kbd{tar xfz archive.tar.gz}
+$ @kbd{GZIP=--best tar cfz archive.tar.gz subdir}
@end smallexample
@noindent
-to explode and unpack.
-
-The difference is that the whole archive is compressed. With
-@command{zip}, archive members are archived individually. @command{tar}'s
-method yields better compression. On the other hand, one can view the
-contents of a @command{zip} archive without having to decompress it. As
-for the @command{tar} and @command{gzip} tandem, you need to decompress the
-archive to see its contents. However, this may be done without needing
-disk space, by using pipes internally:
+Another way would be to avoid the @value{op-gzip} option and run
+@command{gzip} explicitly:
@smallexample
-$ @kbd{tar tfz archive.tar.gz}
+$ @kbd{tar cf - subdir | gzip --best -c - > archive.tar.gz}
@end smallexample
@cindex corrupted archives
lose some compressibility. But this would have make recovering easier.
So, there are pros and cons. We'll see!
-@table @kbd
@item -j
@itemx --bzip2
Filter the archive through @code{bzip2}. Otherwise like @value{op-gzip}.
Filter the archive through @command{compress}. Otherwise like
@value{op-gzip}.
-@item --use-compress-program=@var{prog}
-Filter through @var{prog} (must accept @samp{-d}).
-@end table
-
-@value{op-compress} stores an archive in compressed format. This
-option is useful in saving time over networks and space in pipes, and
-when storage space is at a premium. @value{op-compress} causes
-@command{tar} to compress when writing the archive, or to uncompress when
-reading the archive.
-
-To perform compression and uncompression on the archive, @command{tar}
-runs the @command{compress} utility. @command{tar} uses the default
-compression parameters; if you need to override them, avoid the
-@value{op-compress} option and run the @command{compress} utility
-explicitly. It is useful to be able to call the @command{compress}
-utility from within @command{tar} because the @command{compress} utility by
-itself cannot access remote tape drives.
-
-The @value{op-compress} option will not work in conjunction with the
-@value{op-multi-volume} option or the @value{op-append}, @value{op-update}
-and @value{op-delete} operations. @xref{Operations}, for
-more information on these operations.
+The @acronym{GNU} Project recommends you not use
+@command{compress}, because there is a patent covering the algorithm it
+uses. You could be sued for patent infringement merely by running
+@command{compress}.
-If there is no compress utility available, @command{tar} will report an error.
-@strong{Please note} that the @command{compress} program may be covered by
-a patent, and therefore we recommend you stop using it.
+@item --use-compress-program=@var{prog}
+Use external compression program @var{prog}. Use this option if you
+have a compression program that @GNUTAR{} does not support. There
+are two requirements to which @var{prog} should comply:
-@value{op-bzip2} acts like @value{op-compress}, except that it uses
-the @code{bzip2} utility.
+First, when called without options, it should read data from standard
+input, compress it and output it on standard output.
-@table @kbd
-@item --compress
-@itemx --uncompress
-@itemx -z
-@itemx -Z
-When this option is specified, @command{tar} will compress (when
-writing an archive), or uncompress (when reading an archive). Used in
-conjunction with the @value{op-create}, @value{op-extract},
-@value{op-list} and @value{op-compare} operations.
+Secondly, if called with @option{-d} argument, it should do exactly
+the opposite, i.e. read the compressed data from the standard input
+and produce uncompressed data on the standard output.
@end table
-You can have archives be compressed by using the @value{op-gzip} option.
-This will arrange for @command{tar} to use the @command{gzip} program to be
-used to compress or uncompress the archive wren writing or reading it.
-
-To use the older, obsolete, @command{compress} program, use the
-@value{op-compress} option. The @acronym{GNU} Project recommends you not use
-@command{compress}, because there is a patent covering the algorithm it
-uses. You could be sued for patent infringement merely by running
-@command{compress}.
-
@FIXME{I have one question, or maybe it's a suggestion if there isn't a way
to do it now. I would like to use @value{op-gzip}, but I'd also like
the output to be fed through a program like @acronym{GNU}
Isn't that exactly the role of the @value{op-use-compress-prog} option?
I never tried it myself, but I suspect you may want to write a
@var{prog} script or program able to filter stdin to stdout to
-way you want. It should recognize the @samp{-d} option, for when
+way you want. It should recognize the @option{-d} option, for when
extraction is needed rather than creation.
It has been reported that if one writes compressed data (through the
Extract all protection information.
This option causes @command{tar} to set the modes (access permissions) of
-extracted files exactly as recorded in the archive. If this option
+extracted files exactly as recorded in the archive. If this option
is not used, the current @code{umask} setting limits the permissions
-on extracted files.
+on extracted files. This option is by default enabled when
+@command{tar} is executed by a superuser.
+
This option is meaningless with @value{op-list}.
drive unit that will be used to create the archives) sometimes lowers
the error rates observed at rewriting time.
-I might also use @samp{--number-blocks} instead of
-@samp{--block-number}, so @samp{--block} will then expand to
-@samp{--blocking-factor} unambiguously.
+I might also use @option{--number-blocks} instead of
+@option{--block-number}, so @option{--block} will then expand to
+@option{--blocking-factor} unambiguously.
@node Many
@section Many Archives on One Tape
archive, complete in itself. For example, you can list or extract any
volume alone; just don't specify @value{op-multi-volume}. However, if one
file in the archive is split across volumes, the only way to extract
-it successfully is with a multi-volume extract command @samp{--extract
---multi-volume} (@samp{-xM}) starting on or before the volume where
+it successfully is with a multi-volume extract command @option{--extract
+--multi-volume} (@option{-xM}) starting on or before the volume where
the file begins.
For example, let's presume someone has two tape drives on a system
is automatically added in labels at creation time, it sounded logical to
equally help the user taking care of it when the archive is being read.
-The @value{op-label} was once called @samp{--volume}, but is not available
+The @value{op-label} was once called @option{--volume}, but is not available
under that name anymore.
To find out an archive's label entry (or to find out if an archive has
projects / chaz / tar / blobdiff