Download Tar 1.21

Sergey Poznyakoff, one of the developers at the GNU Project, has provided Tar with a new release with version number 1.21. Tar was originally developed to write files in a file archive to sequential devices, such as a tape streamer, while preserving information from the file system. Today it is mainly used in conjunction with compression programs such as gzip and bzip2 to compress files and folders to a file archive. For more information about Tar, we refer you to this page at Wikipedia. The list of changes since the previous entry in the Meuktracker looks like this:

Version 1.21:

• New short option -J, an alias 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.

  The 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 as expression, eg:
  [code]$ tar –transform ‘s|^|/usr/local/|S'[/code]
  The 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 placed before the expressions, eg:
  [code]$ tar –transform ‘flags=S;s|^|/usr/local/|'[/code]

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

Version 1.20:

• 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 section 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 (eg 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, eg 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. 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 section 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.
• Bug fixes:
  • Fix bug introduced in version 1.19: tar refused to update non-existing archives.