@item File name.
If the name contains any special characters (white space, newlines,
-etc.) these are displayed in an unambiguous form using so called
+etc.)@: these are displayed in an unambiguous form using so called
@dfn{quoting style}. For the detailed discussion of available styles
and on how to use them, see @ref{quoting styles}.
Exclude from dump any directory containing a valid cache directory
tag file. @xref{exclude}.
+@opsummary{exclude-ignore}
+@item --exclude-ignore=@var{file}
+Before dumping a directory, @command{tar} checks if it contains
+@var{file}. If so, exclusion patterns are read from this file.
+The patterns affect only the directory itself. @xref{exclude}.
+
+@opsummary{exclude-ignore-recursive}
+@item --exclude-ignore-recursive=@var{file}
+Before dumping a directory, @command{tar} checks if it contains
+@var{file}. If so, exclusion patterns are read from this file.
+The patterns affect the directory and all itssubdirectories.
+@xref{exclude}.
+
@opsummary{exclude-tag}
@item --exclude-tag=@var{file}
Exclude from dump directories and files, that are internal for some
widely used version control systems.
-@xref{exclude,,exclude-vcs}.
+@xref{exclude-vcs}.
+
+@opsummary{exclude-vcs-ignores}
+@item --exclude-vcs-ignores
+Exclude files that match patterns read from VCS-specific ignore
+files. Supported files are: @file{.cvsignore}, @file{.gitignore},
+@file{.bzrignore}, and @file{.hgignore}. The semantics of each file
+is the same as for the corresponding VCS, e.g. patterns read from
+@file{.gitignore} affect the directory and all its subdirectories.
+@xref{exclude-vcs-ignores}.
@opsummary{file}
@item --file=@var{archive}
directories that are on different file systems from the current
directory.
+@opsummary{one-top-level}
+@item --one-top-level[=@var{dir}]
+Tells @command{tar} to create a new directory beneath the extraction directory
+(or the one passed to @option{-C}) and use it to guard against
+tarbombs. In the absence of @var{dir} argument, the name of the new directory
+will be equal to the base name of the archive (file name minus the
+archive suffix, if recognized). Any member names that do not begin
+with that directory name (after
+transformations from @option{--transform} and
+@option{--strip-components}) will be prefixed with it. Recognized
+file name suffixes are @samp{.tar}, and any compression suffixes
+recognizable by @xref{--auto-compress}.
+
@opsummary{overwrite}
@item --overwrite
this option to produce warning messages about existing old files
(@pxref{warnings}).
+@opsummary{sort}
+@item --sort=@var{order}
+Specify the directory sorting order when reading directories.
+@var{Order} may be one of the following:
+
+@table @samp
+@item none
+No directory sorting is performed. This is the default.
+
+@item name
+Sort the directory entries on name. The operating system may deliver
+directory entries in a more or less random order, and sorting them
+makes archive creation reproducible.
+
+@item inode
+Sort the directory entries on inode number. Sorting directories on
+inode number may reduce the amount of disk seek operations when
+creating an archive for some file systems.
+
+@end table
+
@opsummary{sparse}
@item --sparse
@itemx -S
@smallexample
tar (GNU tar) @value{VERSION}
-Copyright (C) 2013 Free Software Foundation, Inc.
+Copyright (C) 2013-2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
@end smallexample
The @samp{%s} and @samp{%u} in the above example are
-@dfn{meta-characters}. The @samp{%s} meta-character is replaced with
+@dfn{format specifiers}. The @samp{%s} specifier is replaced with
the @dfn{type} of the checkpoint: @samp{write} or
@samp{read} (or a corresponding translated version in locales other
-than @acronym{POSIX}). The @samp{%u} meta-character is replaced with
+than @acronym{POSIX}). The @samp{%u} specifier is replaced with
the ordinal number of the checkpoint. Thus, the above example could
produce the following output when used with the @option{--create}
option:
tar: Hit write checkpoint #30
@end smallexample
-Aside from meta-character expansion, the message string is subject to
+The complete list of available format specifiers follows. Some of
+them can take optional arguments. These arguments, if given, are
+supplied in curly braces between the percent sign and the specifier
+letter.
+
+@table @samp
+@item %s
+Print type of the checkpoint (@samp{write} or @samp{read}).
+
+@item %u
+Print number of the checkpoint.
+
+@item %@{r,w,d@}T
+Print number of bytes transferred so far and approximate transfer
+speed. Optional arguments supply prefixes to be used before number
+of bytes read, written and deleted, correspondingly. If absent,
+they default to @samp{R}. @samp{W}, @samp{D}. Any or all of them can
+be omitted, so, that e.g. @samp{%@{@}T} means to print corresponding
+statistics without any prefixes. Any surplus arguments, if present,
+are silently ignored.
+
+@example
+$ @kbd{tar --delete -f f.tar --checkpoint-action=echo="#%u: %T" main.c}
+tar: #1: R: 0 (0B, 0B/s),W: 0 (0B, 0B/s),D: 0
+tar: #2: R: 10240 (10KiB, 19MiB/s),W: 0 (0B, 0B/s),D: 10240
+@end example
+
+@noindent
+See also the @samp{totals} action, described below.
+
+@item %@{@var{fmt}@}t
+Output current local time using @var{fmt} as format for @command{strftime}
+(@pxref{strftime, strftime,,strftime(3), strftime(3) man page}). The
+@samp{@{@var{fmt}@}} part is optional. If not present, the default
+format is @samp{%c}, i.e. the preferred date and time representation
+for the current locale.
+
+@item %@{@var{n}@}*
+Pad output with spaces to the @var{n}th column. If the
+@samp{@{@var{n}@}} part is omitted, the current screen width
+is assumed.
+
+@item %c
+This is a shortcut for @samp{%@{%Y-%m-%d %H:%M:%S@}t: %ds, %@{read,wrote@}T%*\r},
+intended mainly for use with @samp{ttyout} action (see below).
+@end table
+
+Aside from format expansion, the message string is subject to
@dfn{unquoting}, during which the backslash @dfn{escape sequences} are
replaced with their corresponding @acronym{ASCII} characters
(@pxref{escape sequences}). E.g. the following action will produce an
line, overwriting any previous message:
@smallexample
---checkpoint-action="ttyout=\rHit %s checkpoint #%u"
+--checkpoint-action="ttyout=Hit %s checkpoint #%u%*\r"
@end smallexample
+@noindent
+Notice the use of @samp{%*} specifier to clear out any eventual
+remains of the prior output line. As as more complex example,
+consider this:
+
+@smallexample
+--checkpoint-action=ttyout='%@{%Y-%m-%d %H:%M:%S@}t (%d sec): #%u, %T%*\r'
+@end smallexample
+
+@noindent
+This prints the current local time, number of seconds expired since
+tar was started, the checkpoint ordinal number, transferred bytes and
+average computed I/O speed.
+
@cindex @code{dot}, checkpoint action
Another available checkpoint action is @samp{dot} (or @samp{.}). It
instructs @command{tar} to print a single dot on the standard listing
be abbreviated by placing a dot in front of the checkpoint frequency,
as shown in the previous section.
+@cindex @code{totals}, checkpoint action
+The @samp{totals} action prints the total number of bytes transferred
+so far. The format of the data is the same as for the
+@option{--totals} option (@pxref{totals}). See also @samp{%T} format
+specifier of the @samp{echo} or @samp{ttyout} action.
+
@cindex @code{sleep}, checkpoint action
Yet another action, @samp{sleep}, pauses @command{tar} for a specified
amount of seconds. The following example will stop for 30 seconds at each
@subheading Keywords applicable for @command{tar --extract}
@table @asis
+@kwindex existing-file
+@cindex @samp{%s: skipping existing file}, warning message
+@item existing-file
+@samp{%s: skipping existing file}
@kwindex timestamp
@cindex @samp{implausibly old time stamp %s}, warning message
@cindex @samp{time stamp %s is %s s in the future}, warning message
for more detail).
Notice, that @var{command} is executed once for each regular file
-extracted. Non-regular files (directories, etc.) are ignored when this
+extracted. Non-regular files (directories, etc.)@: are ignored when this
option is used.
@end table
However, empty lines are OK.
+@cindex VCS, excluding patterns from ignore files
+@cindex VCS, ignore files
+@cindex CVS, ignore files
+@cindex Git, ignore files
+@cindex Bazaar, ignore files
+@cindex Mercurial, ignore files
+When archiving directories that are under some version control system (VCS),
+it is often convenient to read exclusion patterns from this VCS'
+ignore files (e.g. @file{.cvsignore}, @file{.gitignore}, etc.) The
+following options provide such possibilty:
+
+@table @option
+@anchor{exclude-vcs-ignores}
+@opindex exclude-vcs-ignores
+@item --exclude-vcs-ignores
+Before archiving a directory, see if it contains any of the following
+files: @file{cvsignore}, @file{.gitignore}, @file{.bzrignore}, or
+@file{.hgignore}. If so, read ignore patterns from these files.
+
+The patterns are treated much as the corresponding VCS would treat
+them, i.e.:
+
+@table @file
+@findex .cvsignore
+@item .cvsignore
+Contains shell-style globbing patterns that apply only to the
+directory where this file resides. No comments are allowed in the
+file. Empty lines are ignored.
+
+@findex .gitignore
+@item .gitignore
+Contains shell-style globbing patterns. Applies to the directory
+where @file{.gitfile} is located and all its subdirectories.
+
+Any line beginning with a @samp{#} is a comment. Backslash escapes
+the comment character.
+
+@findex .bzrignore
+@item .bzrignore
+Contains shell globbing-patterns and regular expressions (if prefixed
+with @samp{RE:}@footnote{According to the Bazaar docs,
+globbing-patterns are Korn-shell style and regular expressions are
+perl-style. As of @GNUTAR{} version @value{VERSION}, these are
+treated as shell-style globs and posix extended regexps. This will be
+fixed in future releases.}. Patterns affect the directory and all its
+subdirectories.
+
+Any line beginning with a @samp{#} is a comment.
+
+@findex .hgignore
+@item .hgignore
+Contains posix regular expressions@footnote{Support for perl-style
+regexps will appear in future releases.}. The line @samp{syntax:
+glob} switches to shell globbing patterns. The line @samp{syntax:
+regexp} switches back. Comments begin with a @samp{#}. Patterns
+affect the directory and all its subdirectories.
+@end table
+
+@opindex exclude-ignore
+@item --exclude-ignore=@var{file}
+Before dumping a directory, @command{tar} checks if it contains
+@var{file}. If so, exclusion patterns are read from this file.
+The patterns affect only the directory itself.
+
+@opindex exclude-ignore-recursive
+@item --exclude-ignore-recursive=@var{file}
+Same as @option{--exclude-ignore}, except that the patterns read
+affect both the directory where @var{file} resides and all its
+subdirectories.
+@end table
+
@table @option
@cindex version control system, excluding files
@cindex VCS, excluding files
@cindex Arch, excluding files
@cindex Mercurial, excluding files
@cindex Darcs, excluding files
+@anchor{exclude-vcs}
@opindex exclude-vcs
@item --exclude-vcs
Exclude files and directories used by following version control
However, this format is designed in such a way that any tar
implementation able to read @samp{ustar} archives will be able to read
most @samp{posix} archives as well, with the only exception that any
-additional information (such as long file names etc.) will in such
+additional information (such as long file names etc.)@: will in such
case be extracted as plain text files along with the files it refers to.
This archive format will be the default format for future versions
compressor names along with each of these options.
You can use any of these options on physical devices (tape drives,
-etc.) and remote files as well as on normal files; data to or from
+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. Most compression
-programs let you override these by setting a program-specific
-environment variable. For example, with @command{gzip} you can set
-@env{GZIP}:
-
-@smallexample
-$ @kbd{GZIP='-9 -n' tar czf archive.tar.gz subdir}
-@end smallexample
-Another way would be to use the @option{-I} option instead (see
+size. The default compression parameters are used.
+You can override them by using the @option{-I} option (see
below), e.g.:
@smallexample
@end smallexample
@noindent
-Finally, the third, traditional, way to do this is to use a pipe:
+A more traditional way to do this is to use a pipe:
@smallexample
$ @kbd{tar cf - subdir | gzip -9 -n > archive.tar.gz}
@item --use-compress-program=@var{command}
@itemx -I=@var{command}
Use external compression program @var{command}. Use this option if you
+want to specify options for the compression program, or if you
are not happy with the compression program associated with the suffix
-at compile time or if you have a compression program that @GNUTAR{}
+at compile time, or if you have a compression program that @GNUTAR{}
does not support. The @var{command} argument is a valid command
invocation, as you would type it at the command line prompt, with any
additional options as needed. Enclose it in quotes if it contains
-white space (see @ref{external, Running External Commands}, for more detail).
+white space (@pxref{external, Running External Commands}).
The @var{command} should follow two conventions:
@subsection Ustar Archive Format
@cindex ustar archive format
-Archive format defined by @acronym{POSIX}.1-1988 specification is called
-@code{ustar}. Although it is more flexible than the V7 format, it
+The archive format defined by the @acronym{POSIX}.1-1988 specification is
+called @code{ustar}. Although it is more flexible than the V7 format, it
still has many restrictions (@pxref{Formats,ustar}, for the detailed
description of @code{ustar} format). Along with V7 format,
@code{ustar} format is a good choice for archives intended to be read
with other implementations of @command{tar}.
-To create archive in @code{ustar} format, use @option{--format=ustar}
-option in conjunction with the @option{--create} (@option{-c}).
+To create an archive in @code{ustar} format, use the @option{--format=ustar}
+option in conjunction with @option{--create} (@option{-c}).
@node gnu
@subsection @acronym{GNU} and old @GNUTAR{} format
This keyword defines the value of the @samp{mtime} field that
is written into the ustar header blocks for the extended headers.
By default, the @samp{mtime} field is set to the modification time
-of the archive member described by that extended headers.
+of the archive member described by that extended header (or to the
+value of the @option{--mtime} option, if supplied).
@item globexthdr.name=@var{string}
This keyword allows user control over the name that is written into
--pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0
@end smallexample
+@noindent
+If you extract files from such an archive and recreate the archive
+from them, you will also need to eliminate changes due to ctime, as
+shown in examples below:
+
+@smallexample
+--pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0,ctime:=0
+@end smallexample
+
+@noindent
+or
+
+@smallexample
+--pax-option=exthdr.name=%d/PaxHeaders/%f,atime:=0,delete=ctime
+@end smallexample
+
@node Checksumming
@subsection Checksumming Problems
SunOS and HP-UX @command{tar} fail to accept archives created using
@GNUTAR{} and containing non-@acronym{ASCII} file names, that
-is, file names having characters with the eight bit set, because they
+is, file names having characters with the eighth bit set, because they
use signed checksums, while @GNUTAR{} uses unsigned
checksums while creating archives, as per @acronym{POSIX} standards. On
-reading, @GNUTAR{} computes both checksums and
-accepts any. It is somewhat worrying that a lot of people may go
+reading, @GNUTAR{} computes both checksums and accepts either of them.
+It is somewhat worrying that a lot of people may go
around doing backup of their files using faulty (or at least
non-standard) software, not learning about it until it's time to
restore their missing files with an incompatible file extractor, or
vice versa.
-@GNUTAR{} computes checksums both ways, and accept
-any on read, so @acronym{GNU} tar can read Sun tapes even with their
+@GNUTAR{} computes checksums both ways, and accepts either of them
+on read, so @acronym{GNU} tar can read Sun tapes even with their
wrong checksums. @GNUTAR{} produces the standard
checksum, however, raising incompatibilities with Sun. That is to
say, @GNUTAR{} has not been modified to
started computing checksums wrongly. When they later realized their
mistake, they merely decided to stay compatible with it, and with
themselves afterwards. Presumably, but I do not really know, HP-UX
-has chosen that their @command{tar} archives to be compatible with Sun's.
+has chosen their @command{tar} archives to be compatible with Sun's.
The current standards do not favor Sun @command{tar} format. In any
case, it now falls on the shoulders of SunOS and HP-UX users to get
a @command{tar} able to read the good archives they receive.
@cindex absolute file names
Unless you use the @option{--absolute-names} (@option{-P}) option,
@GNUTAR{} will not allow you to create an archive that contains
-absolute file names (a file name beginning with @samp{/}.) If you try,
+absolute file names (a file name beginning with @samp{/}). If you try,
@command{tar} will automatically remove the leading @samp{/} from the
file names it stores in the archive. It will also type a warning
message telling you what it is doing.
projects / chaz / tar / blobdiff