tarlz1

Usage

Overview

Tarlz is a massively parallel (multi-threaded) combined implementation of the tar archiver and the lzip compressor. Tarlz uses the compression library lzlib.

Tarlz creates tar archives using a simplified and safer variant of the POSIX pax format compressed in lzip format, keeping the alignment between tar members and lzip members. The resulting multimember tar.lz archive is backward compatible with standard tar tools like GNU tar, which treat it like any other tar.lz archive. Tarlz can append files to the end of such compressed archives.

Keeping the alignment between tar members and lzip members has two advantages. It adds an indexed lzip layer on top of the tar archive, making it possible to decode the archive safely in parallel. It also reduces the amount of data lost in case of corruption.

The tarlz file format is a safe POSIX-style backup format. In case of corruption, tarlz can extract all the undamaged members from the tar.lz archive, skipping over the damaged members, just like the standard (uncompressed) tar. Moreover, the option '--keep-damaged' can be used to recover as much data as possible from each damaged member, and lziprecover can be used to recover some of the damaged members.

Options

-B, --data-size=<bytes>

set target size of input data blocks [2x8=16 MiB]

-C, --directory=<dir>

change to directory <dir>

-f, --file=<archive>

use archive file <archive>

-h, --dereference

follow symlinks; archive the files they point to

-n, --threads=<n>

set number of (de)compression threads [2]

-o, --output=<file>

compress to <file> ('-' for stdout)

-p, --preserve-permissions

don't subtract the umask on extraction

-q, --quiet

suppress all messages

-v, --verbose

verbosely list files processed

-0 .. -9

set compression level [default 6]

--uncompressed

don't compress the archive created

--asolid

create solidly compressed appendable archive

--bsolid

create per block compressed archive (default)

--dsolid

create per directory compressed archive

--no-solid

create per file compressed archive

--solid

create solidly compressed archive

--anonymous

equivalent to '--owner=root --group=root'

--owner=<owner>

use <owner> name/ID for files added to archive

--group=<group>

use <group> name/ID for files added to archive

--exclude=<pattern>

exclude files matching a shell pattern

--ignore-ids

ignore differences in owner and group IDs

--ignore-metadata

compare only file size and file content

--ignore-overflow

ignore mtime overflow differences on 32-bit

--keep-damaged

don't delete partially extracted files

--missing-crc

exit with error status if missing extended CRC

--mtime=<date>

use <date> as mtime for files added to archive

--out-slots=<n>

number of 1 MiB output packets buffered [64]

--warn-newer

warn if any file is newer than the archive

If no archive is specified, tarlz tries to read it from standard input or write it to standard output.

Exit status: 0 for a normal exit, 1 for environmental problems (file not found, files differ, invalid command-line options, I/O errors, etc), 2 to indicate a corrupt or invalid input file, 3 for an internal consistency error (e.g., bug) which caused tarlz to panic.