Improve checkpoint interface.

[chaz/tar] / NEWS

GNU tar NEWS - User visible changes. 2014-01-21
Please send GNU tar bug reports to <bug-tar@gnu.org>

\f
version 1.27.90 (Git)

* New checkpoint action: totals

The --checkpoint-action=totals option instructs tar to output the
total number of bytes transferred at each checkpoint.

* Extended checkpoint format specification.

New conversion specifiers are implemented:

  %d  -  output number of seconds since tar started
  %T  -  output I/O totals
  %{FMT}t - output current local time using FMT as strftime(3) format
            If {FMT} is omitted, use %c
  %{N}*   - pad output with spaces to the Nth column, or to the 
            current screen width, if {N} is not given.

\f
version 1.27.1 - Sergey Poznyakoff, 2013-11-17

* Bug fixes

* Fix unquoting of file names obtained via the -T option.

* Fix GNU long link header timestamp (backward compatibility).

* Fix extracting sparse members from star archives.

\f
version 1.27 - Sergey Poznyakoff, 2013-10-05

* Bug fixes

** Sparse files with large data

When creating a PAX-format archive, tar no longer arbitrarily restricts
the size of the representation of a sparse file to be less than 8 GiB.

* Quoting

In the default C locale, diagnostics and output of 'tar' have been
adjusted to quote 'like this' (with apostrophes) instead of `like this'
(with an accent grave character and an apostrophe).  This tracks
recent changes to the GNU coding standards.

* --owner and --group names and numbers

The --owner and --group options now accept operands of the form
NAME:NUM, so that you can specify both symbolic name and numeric ID
for owner and group.  In these options, NAME no longer needs to be
present in the current host's user and group databases.

* The --keep-old-files and --skip-old-files options.

This release restores the traditional functionality of the
--keep-old-files.  This option causes tar to avoid replacing
existing files while extracting and to treat such files as errors.
Tar will emit a prominent error message upon encountering such files
and will exit with code 2 when finished extracting the archive.

A new option --skip-old-files is introduced, which acts exactly as
--keep-old-files, except that it does not treat existing files as
errors.  Instead it just silently skips them.  An additional level of
verbosity can be obtained by using the option --warning=existing-file
together with this option.

* Support for POSIX ACLs, extended attributes and SELinux context.

Starting with this version tar is able to store, extract and list
extended file attributes, POSIX.1e ACLs and SELinux context.  This is
controlled by the command line options --xattrs, --acls and --selinux,
correspondingly.  Each of these options has a `--no-' counterpart
(e.g. --no-xattrs), which disables the corresponding feature.
Additionally, the options --xattrs-include and --xattrs-exclude allow
you to selectively control for which files to store (or extract) the
extended attributes.

* Passing command line arguments to external commands.

Any option taking a command name as its argument now accepts a full
command line as well.  Thus, it is now possible to pass additional
arguments to invoked programs.  The affected options are:

  --checkpoint-action=exec
  -I, --use-compress-program
  -F, --info-script
  --to-command

Furthermore, if any additional information is supplied to such a
command via environment variables, these variables can now be used in
the command line itself.  Care should be taken to escape them, to
prevent from being expanded too early, for example:

  tar -x -f a.tar --info-script='changevol $TAR_ARCHIVE $TAR_VOLUME'

* New configure option --enable-gcc-warnings, intended for debugging.

* New warning control option --warning=[no-]record-size

On extraction, this option controls whether to display actual record
size, if it differs from the default.

* New command line option --keep-directory-symlink

By default, if trying to extract a directory from the archive,
tar discovers that the corresponding file name already exists and is a
symbolic link, it first unlinks the entry, and then extracts the directory.

This option disables this behavior and instructs tar to follow
symlinks to directories when extracting from the archive.  

It is mainly intended to provide compatibility with the Slackware
installation scripts.

\f
version 1.26 - Sergey Poznyakoff, 2011-03-12

* Bugfixes

** Fix the --verify option, which broke in version 1.24.

** Fix storing long sparse file names in PAX archives.

** Fix correctness of --atime-preserve=replace

tar --atime-preserve=replace no longer tries to restore atime of
zero-sized files.

** Work around POSIX incompatibilities on FreeBSD, NetBSD and Tru64

** Fix bug with --one-file-system --listed-incremental

When invoked with these two options, tar 1.25 would add only the
top-level directory to the archive, but not its contents.

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version 1.25 - Sergey Poznyakoff, 2010-11-07

* Fix extraction of empty directories with the -C option in effect.
* Fix extraction of device nodes.
* Make sure name matching occurs before eventual name transformation.

Tar 1.24 changed the ordering of name matching and name transformation
so that the former saw already transformed file names.  This made it
impossible to match file names in certain cases.  It is fixed now.

* Fix the behavior of tar -x --overwrite on hosts lacking O_NOFOLLOW.

* Improve the testsuite.

* Alternative decompression programs.

If extraction from a compressed archive fails because the corresponding
compression program is not installed and the following two conditions
are met, tar retries extraction using an alternative decompressor:

 1. Another compression program supported by tar is able to handle this
 compression format.
 2. The compression program was not explicitly requested in the command
 line by the use of such options as -z, -j, etc.

For example, if 'compress' is not available, tar will try 'gzip'.

\f
version 1.24 - Sergey Poznyakoff, 2010-10-24

* The --full-time option.

New command line option '--full-time' instructs tar to output file
time stamps to the full resolution.

* Bugfixes.

** More reliable directory traversal when creating archives

Tar now checks for inconsistencies caused when a file system is
modified while tar is creating an archive.  In the new approach, tar
maintains a cache of file descriptors to directories, so it uses more
file descriptors than before, but it adjusts to system limits on
the number of file descriptors.  Tar also takes more care when
a file system is modified while tar is extracting from an archive.

The new checks are implemented via the openat and related calls
standardized by POSIX.1-2008.  On an older system where these calls do
not exist or do not return useful results, tar emulates the calls at
some cost in efficiency and reliability.

** Symbolic link attributes

When extracting symbolic links, tar now restores attributes such as
last-modified time and link permissions, if the operating system
supports this.  For example, recent versions of the Linux kernel
support setting times on symlinks, and some BSD kernels also support
symlink permissions.

** --dereference consistency

The --dereference (-h) option now applies to files that are copied
into or out of archives, independently of other options.  For example,
if F is a symbolic link and archive.tar contains a regular-file member
also named F, "tar --overwrite -x -f archive.tar F" now overwrites F
itself, rather than the file that F points to.  (To overwrite the file
that F points to, add the --dereference (-h) option.)  Formerly,
--dereference was intended to apply only when using the -c option, but
the implementation was not consistent.

Also, the --dereference option no longer affects accesses to other
files, such as archives and time stamp files.  Symbolic links to these
files are always followed.  Previously, the links were usually but not
always followed.

** Spurious error diagnostics on broken pipe.

When receiving SIGPIPE, tar would exit with error status and
"write error" diagnostics. In particular, this occurred if
invoked as in the example below:

   tar tf archive.tar | head -n 1

** --remove-files

'tar --remove-files' failed to remove a directory which contained
symlinks to another files within that directory.

** --test-label behavior

In case of a mismatch, 'tar --test-label LABEL' exits with code 1,
not 2 as it did in previous versions.

The '--verbose' option used with '--test-label' provides additional
diagnostics.

Several volume labels may be specified in a command line, e.g.:

   tar --test-label -f archive 'My volume' 'New volume' 'Test volume'

In this case, tar exits with code 0 if any one of the arguments
matches the actual volume label.

** --label used with --update

The '--label' option can be used with '--update' to prevent accidental
update of an archive:

  tar -rf archive --label 'My volume' .

This did not work in previous versions, in spite of what the docs said.

** --record-size and --tape-length (-L) options

Usual size suffixes are allowed for these options.  For example,
-L10k stands for a 10 kilobyte tape length.

** Fix dead loop on extracting existing symlinks with the -k option.

\f
version 1.23 - Sergey Poznyakoff, 2010-03-10

* Record size autodetection

When listing or extracting archives, the actual record size is
reported only if the archive is read from a device (as opposed
to regular files and pipes).

* Seekable archives

When a read-only operation (e.g. --list or --extract) is requested
on a regular file, tar attemtps to speed up accesses by using lseek.

* New command line option '--warning'

The '--warning' command line option allows to suppress or enable
particular warning messages during 'tar' run.  It takes a single
argument (a 'keyword'), identifying the class of warning messages
to affect.  If the argument is prefixed with 'no-', such warning
messages are suppressed.  For example,

  tar --warning=no-alone-zero-block -x -f archive

suppresses the output of "A lone zero block" diagnostics, which is
normally issued if 'archive' ends with a single block of zeros.

See Tar Manual, section 3.9 "Controlling Warning Messages", for a
detailed discussion.

* New command line option '--level'

The '--level=N' option sets the incremental dump level N.  It
is valid when used in conjunction with the -c and --listed-incremental
options.  So far the only meaningful value for N is 0.  The
'--level=0' option forces creating the level 0 dump, by truncating
the snapshot file if it exists.

* Files removed during incremental dumps

If a file or directory is removed while incremental dump is
in progress, tar exact actions depend on whether this file
was explicitly listed in the command line, or was found
during file system scan.

If the file was explicitly listed in the command line, tar
issues error message and exits with the code 2, meaning
fatal error.

Otherwise, if the file was found during the file system scan,
tar issues a warning, saying "File removed before we read it",
and sets exit code to 1, which means "some files differ".
If the --warning=no-file-removed option is given, no warning
is issued and exit code remains 0.

* Modification times of PAX extended headers.

Modification times in ustar header blocks of extended headers
are set to mtimes of the corresponding archive members.  This
can be overridden by the

  --pax-opion='exthdr.mtime=STRING'

command line option.  The STRING is either number of seconds since
the Epoch or a "Time reference" (see below).

Modification times in ustar header blocks of global extended
headers are set to the time when tar was invoked.

This can be overridden by the

  --pax-opion='globexthdr.mtime=STRING'

command line option.  The STRING is either number of seconds since
the Epoch or a "Time reference" (see below).

* Time references in --pax-option argument.

Any value from the --pax-option argument that is enclosed in a pair
of curly braces represents a time reference.  The string between the
braces is understood either as a textual time representation, as described in
chapter 7, "Date input formats", of the Tar manual, or as a name of
an existing file, starting with '/' or '.'.  In the latter
case, it is replaced with the modification time of that file.

* Environment of --to-command script.

The environment passed to the --to-command script is extended with
the following variables:

   TAR_VERSION          GNU tar version number
   TAR_ARCHIVE          The name of the archive
   TAR_VOLUME           Ordinal number of the volume
   TAR_FORMAT           Format of the archive
   TAR_BLOCKING_FACTOR  Current blocking factor

* Bugfixes
** Fix handling of hard link targets by -c --transform.
** Fix hard links recognition with -c --remove-files.
** Fix restoring files from backup (debian bug #508199).
** Correctly restore modes and permissions on existing directories.
** The --remove-files option removes files only if they were
succesfully stored in the archive.
** Fix storing and listing of the volume labels in POSIX format.
** Improve algorithm for splitting long file names (ustar
format).
** Fix possible memory overflow in the rmt client code (CVE-2010-0624).

\f
version 1.22 - Sergey Poznyakoff, 2009-03-05

* Support for xz compression

Tar uses xz for compression if one of the following conditions is met:

 1. The option --xz or -J (see below) is used.
 2. The xz binary is set as compressor using --use-compress-program option.
 3. The file name of the archive being created ends in '.xz' and
 auto-compress option (-a) is used.

Xz is used for decompression if one of the following conditions is met:

 1. The option --xz or -J is used.
 2. The xz binary is set as compressor using --use-compress-program option.
 3. The file is recognized as xz compressed stream data.

* Short option -J reassigned as a short equivalent of --xz

* New option -I

The -I option is assigned as a short equivalent for
--use-compress-program.

* The --no-recursive option works in incremental mode.

\f
version 1.21 - Sergey Poznyakoff, 2008-12-27

* New short option -J

A shortcut for --lzma.

* New option --lzop

* New option --no-auto-compress

Cancels the effect of previous --auto-compress (-a) option.

* New option --no-null

Cancels the effect of previous --null option.

* Compressed format recognition

If tar is unable to determine archive compression format, it falls
back to using archive suffix to determine it.

* VCS support.

Using --exclude-vcs handles also files used internally by Bazaar,
Mercurial and Darcs.

* Transformation scope flags

Name transformation expressions understand additional flags that
control type of archive members affected by them.  The flags are:

 - r
   Apply transformation to regular archive members.

 - s
   Apply transformation to symbolic link targets.

 - h
   Apply transformation to hard link targets.

Corresponding upper-case letters negate the meaning, so that
'H' means "do not apply transformation to hard link targets".

The scope flags are listed in the third part of an 's' expression,
e.g.:

   tar --transform 's|^|/usr/local/|S'

Default is 'rsh', which means that transformations are applied to
both regular archive members and to the targets of symbolic and hard
links.  If several transform expressions are used, the default flags
can be changed using 'flags=' statement before the expressions, e.g.:

   tar --transform 'flags=S;s|^|/usr/local/|S'

* Bugfixes

** The --null option disabled handling of tar options in list files.  This
is fixed.
** Fixed record size autodetection.  If the detected record size differs from
the expected value (either default one, or the one set from the
command line), tar always prints a warning if verbosity level is set
to 1 or greater, i.e. if either -t or -v option is given.

\f

version 1.20 - Sergey Poznyakoff, 2008-04-14

* New option --auto-compress (-a)

With --create, selects compression algorithm basing on the suffix
of the archive file name.

* New option --lzma

Selects LZMA compression algorithm

* New option --hard-dereference

During archive creation, dereferences hard links and stores the files
they refer to, instead of creating usual hard link members (type '1').

* New option --checkpoint-action

This action allows to specify an action to be executed upon hitting a
checkpoint.  Recognized actions are: dot, echo (the default),
echo=string, ttyout=string, exec=cmdline, and sleep=value.  Any number
of '--checkpoint-action' options can be specified, the actions will be
executed in order of their appearance in the command line.  See
chapter 3.8 "Checkpoints" for a complete description.

* New options --no-check-device, --check-device.

The '--no-check-device' option disables comparing device numbers during
preparatory stage of an incremental dump.  This allows to avoid
creating full dumps if the device numbers change (e.g. when using an
LVM snapshot).

The '--check-device' option enables comparing device numbers.  This is
the default.  This option is provided to undo the effect of the previous
'--no-check-device' option, e.g. if it was set in TAR_OPTIONS
environment variable.

* The --transform option.

Any number of '--transform' options can be given in the command line.
The specified transformations will be applied in turn.

The argument to '--transform' option can be a list of replace
expressions, separated by a semicolon (as in 'sed').

Filename transformations are applied to symbolic link targets
during both creation and extraction.  Tar 1.19 used them only
during extraction.

For a detailed description, see chapter 6.7 "Modifying File and Member
Names".

* Info (end-of-volume) scripts

The value of the blocking factor is made available to info and
checkpoint scripts via environment variable TAR_BLOCKING_FACTOR.

* Incremental archives

Improved (sped up) extracting from incremental archives.

* Bugfixes.
** Fix bug introduced in version 1.19: tar refused to update non-existing
archives.

\f
version 1.19 - Sergey Poznyakoff, 2007-10-10

* New option --exclude-vcs

Excludes directories and files, created by several widely used version
control systems, e.g. "CVS/", ".svn/", etc.

* --exclude-tag and --exclude-cache options

The following options now work with incremental archives as well:

  --exclude-caches
  --exclude-caches-all
  --exclude-tag
  --exclude-tag-all
  --exclude-tag-under

* Fix handling of renamed files in listed incremental archives.

Previous versions always stored absolute file names in rename
records, even if -P was not used. This is fixed: rename records
contain file names processed in accordance with the command line
settings.

* Fix --version output.

* Recognition of broken archives.

When supplied an archive smaller than 512 bytes in reading mode (-x,
-t), the previous version of tar silently ignored it, exiting with
code 0.  It is fixed.  Tar now issues the following diagnostic message:
'This does not look like a tar archive', and exits with code 2.

* Fix double-dot recognition in archive member names in case of duplicate '/.'.

* Fix file padding in case of truncation of the input file to zero size.

\f
version 1.18 - Sergey Poznyakoff, 2007-06-29

* Licensed under the GPLv3

* Fixed several bugs in the testsuite

\f
version 1.17 - Sergey Poznyakoff, 2007-06-08

* Fix archivation of sparse files in posix mode.  Previous versions padded
  sparse members with spurious zero blocks.

* Fix operation of --verify --listed-incremental.  Version 1.16.1 produced
  a full dump when both options were given.

* Fix --occurrence.  In previous versions it continued scanning the archive
  even though all requested members has already been extracted.

* Scope of --transform and --strip-components options.

In addition to affecting regular archive members, the --transform
option affects hard and soft link targets and the --strip-components
option affects hard link targets as well.

* End-of-volume script can send the new volume name to tar by writing
  it to the file descriptor stored in the environment variable TAR_FD.

\f
version 1.16.1 - Sergey Poznyakoff, 2006-12-09

* New option --exclude-tag allows to specify "exclusion tag files", i.e.
  files whose presence in a directory means that the directory should not
  be archived.

* The --exclude-cache option excludes directories that contain the
  CACHEDIR.TAG file from being archived.  Previous versions excluded
  directory contents only, while the directories themselves were
  still added to the archive.

* Support for reading ustar type 'N' header logical records has been removed.
  This GNU extension was generated only by very old versions of GNU 'tar'.
  Unfortunately its implementation had security holes; see
  <http://archives.neohapsis.com/archives/fulldisclosure/2006-11/0344.html>.
  We don't expect that any tar archives in practical use have type 'N'
  records, but if you have one and you trust its contents, you can
  decode it with GNU tar 1.16 or earlier.

* Race conditions have been fixed that in some cases briefly allowed
  files extracted by 'tar -x --same-owner' (or plain 'tar -x', when
  running as root) to be accessed by users that they shouldn't have been.

\f
version 1.16 - Sergey Poznyakoff, 2006-10-21

* After creating an archive, tar exits with code 1 if some files were
changed while being read.  Previous versions exited with code 2 (fatal
error), and only if some files were truncated while being archived.

* New option --mtime allows to set modification times for all archive
members during creation.

* Bug fixes
** Avoid running off file descriptors when using multiple -C options.
** tar --index-file=FILE --file=- sent the archive to FILE, and
the listing to stderr.

\f
version 1.15.91 - Sergey Poznyakoff, 2006-06-16

* Incompatible changes

** Globbing

Previous versions of GNU tar assumed shell-style globbing when
extracting from or listing an archive.  For example:

  tar xf foo.tar '*.c'

would extract all files whose names end in '.c'.  This behavior
was not documented and was incompatible with traditional tar
implementations.  Therefore, starting from this version, GNU tar
no longer uses globbing by default.  For example, the above invocation
is now interpreted as a request to extract from the archive the file
named '*.c'.

To treat member names as globbing patterns, use --wildcards option.
If you wish tar to mimic the behavior of versions up to 1.15.90,
add --wildcards to the value of the environment variable TAR_OPTIONS.

The exact way in which tar interprets member names is controlled by the
following command line options:

     --wildcards              use wildcards
     --anchored               patterns match file name start
     --ignore-case            ignore case
     --wildcards-match-slash  wildcards match '/'

Each of these options has a '--no-' counterpart that disables its
effect (e.g. --no-wildcards).

These options affect both the interpretation of member names from
command line and that of the exclusion patterns (given with --exclude
and --exclude-from options). The defaults are:

 1. For member names: --no-wildcards --anchored
 2. For exclusion patterns: --wildcards --no-anchored --wildcards-match-slash

The options can appear multiple times in the command line, thereby
changing the way command line arguments are interpreted.  For example,
to use case-insensitive matching in exclude patterns and to revert to
case-sensitive matching for the rest of command line, one could write:

  tar xf foo.tar --ignore-case --exclude-from=FILE --no-ignore-case file.name

** Short option -l is now an alias of --check-links option, which complies
with UNIX98.  This ends the transition period started with version 1.14.

* New features

** New option --transform allows to transform file names before storing them
in the archive or member names before extracting.  The option takes a
sed replace expression as its argument.  For example,

  tar cf foo.tar --transform 's,^,prefix/,'

will add 'prefix/' to all file names stored in foo.tar.

** --strip-components option works when deleting and comparing.  In previous
versions it worked only with --extract.

** New option --show-transformed-names enables display of transformed file
or archive.   It generalizes --show-stored-names option, introduced in
1.15.90.  In particular, when creating an archive in verbose mode, it lists
member names as stored in the archive, i.e., with any eventual prefixes
removed and file name transformations applied.  The option is useful,
for example, while comparing 'tar cv' and 'tar tv' outputs.

** New incremental snapshot file format keeps information about file names
as well as that about directories.

** The --checkpoint option takes an optional argument specifying the number
of records between the two successive checkpoints.   Optional dot
starting the argument intructs tar to print dots instead of textual
checkpoints.

** The --totals option can be used with any tar operation (previous versions
understood it only with --create).  If an argument to this option is
given, it specifies the signal upon delivery of which the statistics
is to be printed.  Both forms of this option (with and without
argument) can be given to in a single invocation of tar.

* Bug fixes
** Detect attempts to update compressed archives.

\f
version 1.15.90 - Sergey Poznyakoff, 2006-02-19

* New features

** Any number of -T (--files-from) options may be used in the command line.
The file specified with -T may include any valid 'tar' options,
including another -T option.
Compatibility note: older versions of tar would only recognize -C
as an option name within the file list file.  Now any file whose name
starts with - is handled as an option.  To insert file names starting with
dash, use the --add-file option.

** List files containing null-separated file names are detected and processed
automatically.  It is no longer necessary to give the --null option.

** New option --no-unquote disables the unquoting of input file names.
This is useful for processing output from 'find dir -print0'.
An orthogonal option --unquote is provided as well.

** New option --test-label tests the archive volume label.
If an argument is specified, the label is compared against its value.
Tar exits with code 0 if the two strings match, and with code 2 if
they do not.

If no argument is given, the --verbose option is implied.  In this case,
tar prints the label name if present and exits with code 0.

** New option --show-stored-names.  When creating an archive in verbose mode,
it lists member names as stored in the archive, i.e., with any eventual
prefixes removed.  The option is useful, for example, while comparing
'tar cv' and 'tar tv' outputs.

** New option --to-command pipes the contents of archive members to the
specified command.

** New option --atime-preserve=system, which uses the O_NOATIME feature
of recent Linux kernels to avoid some problems when preserving file
access times.

** New option --delay-directory-restore delays restoring modification times
and permissions of extracted directories until the end of extraction.
This is necessary for restoring from archives with unusual member
ordering (in particular, those created with --no-recursion option).
This option is implied when restoring from incremental archives.

** New option --restrict prohibits use of some potentially harmful tar
options.  Currently it disables '!' escape in multi-volume name menu.

** New options --quoting-style and --quote-chars control the way tar
quotes member names on output. The --quoting-style takes an argument
specifying the quoting style to use (literal, shell, shell-always,
c, escape, locale, clocale). The argument to --quote-chars is a string
specifying characters to quote, even if the selected quoting style
would not quote them otherwise. The option --no-quote-chars is
provided to disable quoting certain characters.

** The end-of-volume script (introduced with --info-script option) can
get current archive name from the environment variable TAR_ARCHIVE and
the volume number from the variable TAR_VOLUME.  It can alter the
archive name by writing new name to the file descriptor 3.

** Better support for full-resolution time stamps.  Tar cannot restore
time stamps to full nanosecond resolution, though, until the kernel
guys get their act together and give us a system call to set file time
stamps to nanosecond resolution.

** The -v option now prints time stamps only to 1-minute resolution,
not full resolution, to avoid using up too many output columns.
Nanosecond resolution is now supported, but that would be too much.

* Bug fixes

** Allow non-option arguments to be interspersed with options.
** When extracting or listing archives in old GNU format, tar
used to read an extra block of data after a long name header
if length of the member name was divisible by block size (512).
Consequently, the file pointer was set off and the next member
was not processed correctly.
** Previous version created invalid archives when files shrink
during reading.
** Compare mode (tar d) hung when trying to compare file contents.
** Previous versions in certain cases failed to restore directory
modification times.
** When creating an archive, do not attempt to store files whose
meta-data cannot be stored in the header due to format limitations
(for ustar and v7 formats).
** The --version option now also outputs information about copyright,
license, and credits.  This reverts to the behavior of tar 1.14 and
earlier, and conforms to the GNU coding standards.  The --license (-L)
option introduced in tar 1.15 has been removed, since it's no longer
needed.

\f
version 1.15.1 - Sergey Poznyakoff, 2004-12-21

This version fixes a bug introduced in 1.15 which caused
tar to refuse to extract files from standard input.

\f
version 1.15 - Sergey Poznyakoff, 2004-12-20

* Compressed archives are recognised automatically, it is no longer
necessary to specify -Z, -z, or -j options to read them.  Thus, you can
now run 'tar tf archive.tar.gz'.

* When restoring incremental dumps, --one-file-system option
prevents directory hierarchies residing on different devices
from being purged.

With the previous versions of tar it was dangerous to create
incremental dumps with --one-file-system option, since they
would recursively remove mount points when restoring from the
back up.  This change fixes the bug.

* Renamed --strip-path to --strip-components for consistency with
the GNU convention.

* Skipping archive members is sped up if the archive media supports
seeks.

* Restore script starts restoring only if it is given --all (-a) option,
or some patterns.  This is to prevent accidental restores.

* 'tar --verify' prints a warning if during archive creation some of
the file names had their prefixes stripped off.

* New option --exclude-caches instructs tar to exclude cache directories
automatically on archive creation.  Cache directories are those
containing a standardized tag file, as specified at:

        http://www.brynosaurus.com/cachedir/spec.html

* New configure option --with-rmt allows to specify full path name to
the 'rmt' utility.  This supersedes DEFAULT_RMT_COMMAND variable
introduced in version 1.14

* New configure variable DEFAULT_RMT_DIR allows to specify the directory
where to install 'rmt' utility.  This is necessary since modifying
--libexecdir as was suggested for version 1.14 produced a side effect: it
also modified installation prefix for backup scripts (if
--enable-backup-scripts was given).

* Bug fixes:
** Fixed flow in recognizing files to be included in incremental dumps.
** Correctly recognize sparse archive members when used with -T option.
** GNU multivolume headers cannot store filenames longer than 100 characters.
Do not allow multivolume archives to begin with such filenames.
** If a member with link count > 2 was stored in the archive twice,
previous versions of tar were not able to extract it, since they
were trying to link the file to itself, which always failed and
lead to removing the already extracted copy.  Preserve the first
extracted copy in such cases.
** Restore script was passing improper argument to tar --listed option (which
didn't affect the functionality, but was logically incorrect).
** Fixed verification of created archives.
** Fixed unquoting of file names containing backslash escapes (previous
versions failed to recognize \a and \v).
** When attempting to delete a non-existing member from the archive, previous
versions of tar used to overwrite last archive block with zeroes.

\f
version 1.14 - Sergey Poznyakoff, 2004-05-11

* Added support for POSIX.1-2001 and ustar archive formats.
* New option --format allows to select the output archive format
* The default output format can be selected at configuration time
  by presetting the environment variable DEFAULT_ARCHIVE_FORMAT.
  Allowed values are GNU, V7, OLDGNU and POSIX.
* New option --strip-path allows to cut off a given number of
  path elements from the name of the file being extracted.

* New options --index-file, --no-overwrite-dir.  The --overwrite-dir
  option is now the default; use --no-overwrite-dir if you prefer
  the previous default behavior.

* The semantics of -o option is changed.  When extracting, it
  does the same as --no-same-owner GNU tar option.  This is compatible
  with UNIX98 tar.  Otherwise, its effect is the same as that of
  --old-archive option.  This latter is deprecated and will be removed
  in future.

* New option --check-links prints a message if not all links are dumped
  for a file being archived.  This corresponds to the UNIX98 -l option.
  The current semantics of the -l option is retained for compatibility
  with previous releases, however such usage is strongly deprecated as
  the option will change to its UNIX98 semantics in the future releases.

* New option --occurrence[=N] can be used in conjunction with one of
  the subcommands --delete, --diff, --extract or --list when a list of
  files is given either on the command line or via -T option.  This
  option instructs tar to process only the Nth occurrence of each named
  file.  N defaults to 1, so 'tar -x -f archive --occurrence filename'
  extracts the first occurrence of 'filename' from 'archive'
  and terminates without scanning to the end of the archive.

* New option --pax-option allows to control the handling of POSIX
  keywords in 'pax' extended headers.  It is equivalent to 'pax'
  -o option.

* --incremental and --listed-incremental options work correctly on
  individual files, as well as on directories.

* New scripts: backup (replaces old level-0 and level-1) and restore.
The scripts are compiled and installed if --enable-backup-scripts
option is given to configure.

* By default tar searches "rmt" utility in "$prefix/libexec/rmt",
which is consistent with the location where the version of "rmt"
included in the package is installed.  Previous versions of tar
used "/etc/rmt".  To install "rmt" to its traditional location,
run configure with option --libexecdir=/etc.  Otherwise, if you
already have rmt installed and wish to use it, instead of the
shipped in version, set the variable DEFAULT_RMT_COMMAND to
the full path name of the utility, e.g., ./configure
DEFAULT_RMT_COMMAND=/etc/rmt.

Notice also that the full path name of the "rmt" utility to
use can be set at runtime, by giving option --rmt-command to
tar.

* Removed obsolete command line options:
** --absolute-paths superseded by --absolute-names
** --block-compress is not needed any longer
** --block-size superseded by --blocking-factor
** --modification-time superseded by --touch
** --read-full-blocks superseded by --read-full-records
** --record-number superseded by --block-number
** --version-control superseded by --backup

* New message translations fi (Finnish), gl (Galician), hr (Croatian),
  hu (Hungarian), ms (Malaysian), nb (Norwegian), ro (Romanian), sk
  (Slovak), zh_CN (Chinese simplified), zh_TW (Chinese traditional).
  The code 'no' for Norwegian (Bokmål) has been withdrawn; use 'nb' instead.

* Bug fixes.

\f
version 1.13.25 - Paul Eggert, 2001-09-26

* Bug fixes.

\f
version 1.13.24 - Paul Eggert, 2001-09-22

* New option --overwrite-dir.
* Fixes for buffer overrun, porting, and copyright notice problems.
* The message translations for Korean are available again.

\f
version 1.13.23 - Paul Eggert, 2001-09-13

* Bug, porting, and copyright notice fixes.

\f
version 1.13.22 - Paul Eggert, 2001-08-29

* Bug fixes.

\f
version 1.13.21 - Paul Eggert, 2001-08-28

* Porting and copyright notice fixes.

\f
version 1.13.20 - Paul Eggert, 2001-08-27

* Some bugs were fixed:
  - security problems
  - hard links to symbolic links

* New option --recursion (the default) that is the inverse of --no-recursion.

* New options --anchored, --ignore-case, --wildcards,
  --wildcards-match-slash, and their negations (e.g., --no-anchored).
  Along with --recursion and --no-recursion, these options control how
  exclude patterns are interpreted.

* The default interpretation of exclude patterns is now --no-anchored
  --no-ignore-case --recursion --wildcards --wildcards-match-slash.
  This is a quiet change to the semantics of --exclude.  The previous
  semantics were a failed attempt at backward compatibility but it
  became clear that the semantics were puzzling and did not satisfy
  everybody.  Rather than continue to try to revive that dead horse we
  thought it better to substitute cleaner semantics, with options so
  that you can change the behavior more to your liking.

* New message translations for Indonesian and Turkish.
  The translation for Korean has been withdrawn due to encoding errors.
  It will be reissued once those are fixed.

\f
version 1.13.19 - Paul Eggert, 2001-01-13

* The -I option has been withdrawn, as it was buggy and confusing.
  Eventually it is planned to be reintroduced, with the same meaning as -T.

* With an option like -N DATE, if DATE starts with "/" or ".", it is taken
  to be a file name; the last-modified time of that file is used as the date.

\f
version 1.13.18 - Paul Eggert, 2000-10-29

* Some security problems have been fixed.  'tar -x' now modifies only
  files under the working directory, unless you also specify an unsafe
  option like --absolute-names or --overwrite.

* The short name of the --bzip option has been changed to -j,
  and -I is now an alias for -T, for compatibility with Solaris tar.

* The manual is now distributed under the GNU Free Documentation License.

* The new environment variable TAR_OPTIONS holds default command-line options.

* The --no-recursion option now affects extraction too.

* The wording in some diagnostics has been changed slightly.

* Snapshot files now record whether each file was accessed via NFS.
  The new file format is upward- and downward-compatible with the old.

* New language supported: da.

* Compilation by traditional (K&R) C compilers is no longer supported.
  If you still use such a compiler, please use GCC instead.

* This version of tar works best with GNU gzip test version 1.3 or later.
  Please see <ftp://alpha.gnu.org/gnu/gzip/>.

* 'tar --delete -f -' now works again.

\f
version 1.13.17 - Paul Eggert, 2000-01-07.

* 'tar --delete -f -' is no longer allowed; it was too buggy.
* Diagnostic messages have been made more regular and consistent.

\f
version 1.13.16 - Paul Eggert, 1999-12-13.

* By default, tar now refuses to overwrite an existing file when
  extracting files from an archive; instead, it removes the file
  before extracting it.  If the existing file is a symbolic link, the
  link is removed and not the pointed-to file.  There is one
  exception: existing nonempty directories are not removed, nor are
  their ownerships or permissions extracted.  This fixes some
  longstanding security problems.

  The new --overwrite option enables the old default behavior.

  For regular files, tar implements this change by using the O_EXCL
  option of 'open' to ensure that it creates the file; if this fails, it
  removes the file and tries again.  This is similar to the behavior of
  the --unlink-first option, but it is faster in the common case of
  extracting a new directory.

* By default, tar now ignores file names containing a component of '..'
  when extracting, and warns about such file names when creating an archive.
  To enable the old behavior, use the -P or --absolute-names option.

* Tar now handles file names with multibyte encodings (e.g., UTF-8, Shift-JIS)
  correctly.  It relies on the mbrtowc function to handle multibyte characters.

* The file generated by -g or --listed-incremental now uses a format
  that is independent of locale, so that users need not worry about
  locale when restoring a backup.  This is needed for proper support
  of multibyte characters.  Old-format files can still be read, and
  older versions of GNU tar can read new-format files, unless member
  names have multibyte chars.

* Many diagnostics have been changed slightly, so that file names are
  now output unambiguously.  File names in diagnostics now are either
  `quoted like this' (in the default C locale) or are followed by
  colon, newline, or space, depending on context.  Unprintable
  characters are escaped with a C-like backslash conventions.
  Terminating characters (e.g., close-quote, colon, newline)
  are also escaped as needed.

* tar now ignores socket files when creating an archive.
  Previously tar archived sockets as fifos, which caused problems.

\f
version 1.13.15 - Paul Eggert, 1999-12-03.

* If a file's ctime changes when being archived, report an error.
  Previously tar looked at mtime, which missed some errors.

\f
version 1.13.14 - Paul Eggert, 1999-11-07.

* New translations ja, pt_BR.
* New options --help and --version for rmt.
* Ignore Solaris door files when creating an archive.

\f
version 1.13.13 - Paul Eggert, 1999-10-11.

* Invalid headers in tar files now elicit errors, not just warnings.
* 'tar --version' output conforms to the latest GNU coding standards.
* If you specify an invalid date, 'tar' now substitutes (time_t) -1.
* 'configure --with-dmalloc' is no longer available.

\f
version 1.13.12 - Paul Eggert, 1999-09-24.

* 'tar' now supports hard links to symbolic links.

* New options --no-same-owner, --no-same-permissions.

* --total now also outputs a human-readable size, and a throughput value.

* 'tar' now uses two's-complement base-256 when outputting header
  values that are out of the range of the standard unsigned base-8
  format.  This affects archive members with negative or huge time
  stamps or uids, and archive members 8 GB or larger.  The new tar
  archives cannot be read by traditional tar, or by older versions of
  GNU tar.  Use the --old-archive option to revert to the old
  behavior, which uses unportable representations for negative values,
  and which rejects large files.

* On 32-bit hosts, 'tar' now assumes that an incoming time stamp T in
  the range 2**31 <= T < 2**32 represents the negative time (T -
  2**32).  This behavior is nonstandard and is not portable to 64-bit
  time_t hosts, so 'tar' issues a warning.

* 'tar' no longer gives up extracting immediately upon discovering
  that an archive contains garbage at the end.  It attempts to extract
  as many files as possible from the good data before the garbage.

* A read error now causes a nonzero exit status, not just a warning.

* Some diagnostics have been reworded for consistency.

\f
version 1.13.11 - Paul Eggert, 1999-08-23.

* The short name of the --bzip option has been changed to -I,
  for compatibility with paxutils.

* -T /dev/null now matches nothing; previously, it matched anything
  if no explicit operands were given.

* The '--' option now works the same as with other GNU utilities;
  it causes later operands to be interpreted as file names, not options,
  even if they begin with '-'.

* For the --newer and --after-date options, the table of time zone
  abbreviations like 'EST' has been updated to match current practice.
  Also, local time abbreviations are now recognized, even if they are
  not in tar's hardwired table.  Remember, though, that you should use
  numeric UTC offsets like '-0500' instead of abbreviations like
  'EST', as abbreviations are not standardized and are ambiguous.

\f
version 1.13.10 - Paul Eggert, 1999-08-20.

* 'tar' now uses signed base-64 when outputting header values that are
  out of the range of the standard unsigned base-8 format.  [This
  change was superseded in 1.13.12, described above.]

\f
version 1.13.9 - Paul Eggert, 1999-08-18.

* 'tar' now writes two zero blocks at end-of-archive instead of just one.
  POSIX.1 requires this, and some other 'tar' implementations check for it.

* 'tar' no longer silently accepts a block containing nonzero checksum bytes
  as a zero block.

* 'tar' now reads buggy tar files that have a null byte at the start of a
  numeric header field.

\f
version 1.13.8 - Paul Eggert, 1999-08-16.

* For compatibility with traditional 'tar', intermediate directories
  created automatically by root are no longer given the uid and gid of
  the original file or directory.

\f
version 1.13.7 - Paul Eggert, 1999-08-14.

* --listed-incremental and --newer are now incompatible options.

* When creating an archive, leading './' is no longer stripped,
  to match traditional tar's behavior (and simplify the documentation).

* --diff without --absolute-names no longer falls back on absolute names.

\f
version 1.13.6 - Paul Eggert, 1999-08-11.

* An --exclude pattern containing / now excludes a file only if it matches an
  initial prefix of the file name; a pattern without / continues to
  exclude a file if it matches any file name component.

* The protocol for talking to rmt has been extended slightly.
  Open flags are now communicated in symbolic format as well as numeric.
  The symbolic format (e.g., "O_WRONLY|O_CREAT|O_TRUNC") is for portability
  when rmt is operating on a different operating system from tar.
  The numeric format is retained, and rmt uses it if symbolic format is absent,
  for backward compatibility with older versions of tar and rmt.

* When writing GNU tar format headers, tar now uses signed base-64
  for values that cannot be represented in unsigned octal.
  This supports larger files (2**66 - 1 bytes instead of 2**33 - 1 bytes),
  larger uids, negative time stamps, etc.

* When extracting files with unknown ownership, tar now looks up the
  uid and gid "nobody" on hosts whose headers do not define UID_NOBODY
  and GID_NOBODY, and falls back on uid/gid -2 if there is no "nobody".

* tar -t --numeric-owner now prints numeric uids and gids, not symbolic.

* New option -y or --bzip2 for bzip2 compression, by popular request.

\f
version 1.13.5 - Paul Eggert, 1999-07-20.

* Do the delayed updates of file metadata even after a fatal error.

\f
version 1.13.4 - Paul Eggert, 1999-07-20.

* Do not chmod unless we are root or the -p option was given;
  this matches historical practice.

\f
version 1.13.3 - Paul Eggert, 1999-07-16.

* A path name is excluded if any of its file name components matches an
  excluded pattern, even if the path name was specified on the command line.
  Also see 1.13.6 for later changes in this area.

\f
version 1.13.2 - Paul Eggert, 1999-07-14.

* Bug reporting address changed to <bug-tar@gnu.org>.

\f
version 1.13.1 - Paul Eggert, 1999-07-12.

* Bug fixes only.
\f
version 1.13 - Paul Eggert, 1999-07-08.

* Support for large files, e.g., files larger than 2 GB on many 32-bit hosts.
  Also, support for larger uids, device ids, etc.
* Many bug fixes and porting fixes.
* This release is only for fixes.  A more ambitious test release,
  with new features, is available as part of the paxutils.  Please see:
    ftp://alpha.gnu.org/gnu/paxutils/
  The fixes in this release are intended to be merged with paxutils
  at some point, but they haven't been merged yet.
* An interim GNU tar alpha had new --bzip2 and --ending-file options,
  but they have been removed to maintain compatibility with paxutils.
  Please try --use=bzip2 instead of --bzip2.
\f
Version 1.12 - François Pinard, 1997-04.

Sensitive matters
* Use shell globbing patterns for --label, instead of regular expressions.
* Do not quote anymore internally over the quoting done by the shell.

Output for humans
* Offer internationalization capabilities of most recent GNU gettext.
* Messages available in many more languages, thanks to all translators!
* Usage of ISO 8601 dates in listings, instead of local American dates.
* More normalization and cleanup in error messages.

Creation
* For helping using tar with find, offer a --no-recursion option.
* Implement --numeric-owner for ignoring symbolic names at create time.
* New --owner, --group --mode options, still preliminary.
* Recognize creating an archive on /dev/null, so Amanda works faster.
* Object to the creation of an empty archive (like in 'tar cf FILE').
* Barely start implementing --posix and POSIXLY_CORRECT.

Extraction
* Make a better job at restoring file and directory attributes.
* Automatically attempt deleting existing files when in the way.
* Option --unlink-first (-U) removes most files prior to extraction.
* Option --recursive-unlink removes non-empty directories when in the way.
* Option --numeric-owner ignores owner/group names, it uses UID/GID instead.
* Use global umask when creating missing intermediate directories.
* When symlinks are not available, extract symbolic links as hard links.
* Diagnose extraction of contiguous files as regular files.
* New --backup, --suffix and --version-control options.

Various changes
* Better support of huge archives with --tape-length and --totals.
* Rename option --read-full-blocks (-B) to --read-full-records (-B).
* Rename option --block-size (-b) to --blocking-factor (-b).
* Rename option --record-number (-R) to --block-number (-R).
* With --block-number (-R), report null blocks and end of file.
* Implement --record-size for introducing a size in bytes.
* Delete --block-compress option and rather decide it automatically.
* Rename option --modification-time to --touch.

Many bugs are squashed, while others still run free.
\f
Version 1.11.8 - François Pinard, 1995-06.

* Messages available in French, German, Portuguese and Swedish.
* The distribution provides a rudimentary Texinfo manual.
* The device defaults to stdin/stdout, unless overridden by the installer.
* Option --sparse (-S) should work on more systems.
* Option --rsh-command may select an alternative remote shell program.

Most changes are internal, and should yield better portability.
\f
Version 1.11.2 - Michael Bushnell, 1993-03.

* Changes in backup scripts: cleaned up considerably; notices error
conditions better over rsh; DUMP_REMIND_SCRIPT is now an option in
backup-specs; new file dump-remind is an example of a
DUMP_REMIND_SCRIPT.

* Superfluous "Reading dirname" was a bug; fixed.

* Incompatibility problems with a bug on Solaris are fixed.

* New option --gzip (aliases are --ungzip and -z); calls gzip instead
of compress.  Also, --use-compress-program lets you specify any
compress program.  --compress-block is renamed --block-compress and
now requires one of the three compression options to be specified.

* Several error messages are cleaned up.

* Directory owners are now set properly when running as root.

* Provide DUMP_REMIND_SCRIPT in backup-specs as a possible option
for --info-script.

* Behave better with broken rmt servers.

* Dump scripts no longer use --atime-preserve; this causes a nasty probem.

* Several Makefile cleanups.
\f
Version 1.11.1 - Michael Bushnell, 1992-09.

* Many bug fixes.
\f
Version 1.11 - Michael Bushnell, 1992-09.
Version 1.10.16 - 1992-07.
Version 1.10.15 - 1992-06.
Version 1.10.14 - 1992-05.
Version 1.10.13 - 1992-01.

* Many bug fixes.

* Now uses GNU standard configure, generated by Autoconf.

* Long options now use '--'; use of '+' is deprecated and support
for it will eventually be removed.

* New option --null causes filenames read by -T to be
null-terminated, and causes -C to be ignored.

* New option --remove-files deletes files (but not directories)
after they are added to the archive.

* New option --ignore-failed-read prevents read-errors from affecting
the exit status.

* New option --checkpoint prints occasional messages as the tape
is being read or written.

* New option --show-omitted-dirs prints the names of directories
omitted from the archive.

* Some tape drives which use a non-standard method of indicating
end-of-tape now work correctly with multi-tape archives.

* --volno-file: Read the volume number used in prompting the user
(but not in recording volume ID's on the archive) from a file.

* When using --multi-volume, you can now give multiple -f arguments;
the various tape drives will get used in sequence and then wrap
around to the beginning.

* Remote archive names no longer have to be in /dev: any file with a
':' is interpreted as remote.  If new option --force-local is given,
then even archive files with a ':' are considered local.

* New option --atime-preserve restores (if possible) atimes to
their original values after dumping the file.

* No longer does tar confusingly dump "." when you don't tell it
what to dump.

* When extracting directories, tar now correctly restores their
modification and access times.

* Longnames support is redone differently--long name info directly
precedes the long-named file or link in the archive, so you no
longer have to wait for the extract to hit the end of the tape for
long names to work.
\f
Version 1.10 - Michael Bushnell, 1991-07.

* Filename to -G is optional.  -C works right.  Names +newer and
+newer-mtime work right.

* -g is now +incremental, -G is now +listed-incremental.

* Sparse files now work correctly.

* +volume is now called +label.

* +exclude now takes a filename argument, and +exclude-from does
what +exclude used to do.

* Exit status is now correct.

* +totals keeps track of total I/O and prints it when tar exits.

* When using +label with +extract, the label is now a regexp.

* New option +tape-length (-L) does multi-volume handling like BSD
dump: you tell tar how big the tape is and it will prompt at that
point instead of waiting for a write error.

* New backup scripts level-0 and level-1 which might be useful
to people.  They use a file "backup-specs" for information, and
shouldn't need local modification.  These are what we use to do
all our backups at the FSF.
\f
Version 1.09 - Jay Fenlason, 1990-10.
Version 1.08 - Jay Fenlason, 1990-01.
Versions 1.07 back to 1.00 by Jay Fenlason.

* See ChangeLog for more details.

\f

Copyright 1994-2001, 2003-2010, 2013 Free Software Foundation, Inc.

This file is part of GNU tar.

GNU tar is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

GNU tar is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
\f
Local variables:
mode: outline
paragraph-separate: "[  \f]*$"
eval: (add-hook 'write-file-hooks 'time-stamp)
time-stamp-start: "changes. "
time-stamp-format: "%:y-%02m-%02d"
time-stamp-end: "\n"
end: