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In
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
, tar is a computer software utility for collecting many files into one
archive file In computing, an archive file is a computer file that is composed of one or more files along with metadata. Archive files are used to collect multiple data files together into a single file for easier portability and storage, or simply to compre ...
, often referred to as a tarball, for
distribution Distribution may refer to: Mathematics * Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a vari ...
or backup purposes. The name is derived from "tape archive", as it was originally developed to write data to sequential I/O devices with no file system of their own. The archive data sets created by tar contain various
file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...
parameters, such as name, timestamps, ownership, file-access permissions, and
directory Directory may refer to: * Directory (computing), or folder, a file system structure in which to store computer files * Directory (OpenVMS command) * Directory service, a software application for organizing information about a computer network' ...
organization. POSIX abandoned ''tar'' in favor of '' pax'', yet ''tar'' sees continued widespread use.


History

The command-line utility was first introduced in the
Version 7 Unix Seventh Edition Unix, also called Version 7 Unix, Version 7 or just V7, was an important early release of the Unix operating system. V7, released in 1979, was the last Bell Laboratories release to see widespread distribution before the commercial ...
in January 1979, replacing the tp program (which in turn replaced "tap"). The file structure to store this information was standardized in
POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming in ...
.1-1988 and later POSIX.1-2001, and became a format supported by most modern file archiving systems. The tar command was abandoned in POSIX.1-2001 in favor of pax command, which was to support ustar file format; the tar command was indicated for withdrawal in favor of pax command at least since 1994. Today,
Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...
operating systems usually include tools to support tar files, as well as utilities commonly used to compress them, such as
gzip gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and i ...
and bzip2. The command has also been ported to the
IBM i IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS i ...
operating system. BSD-tar has been included in
Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
since Windows 10 April 2018 Update, and there are otherwise multiple third party tools available to read and write these formats on Windows.


Rationale

Many historic tape drives read and write variable-length data blocks, leaving significant wasted space on the tape between blocks (for the tape to physically start and stop moving). Some tape drives (and raw disks) support only fixed-length data blocks. Also, when writing to any medium such as a file system or network, it takes less time to write one large block than many small blocks. Therefore, the tar command writes data in records of many 512  B blocks. The user can specify a blocking factor, which is the number of blocks per record. The default is 20, producing 10 
KiB The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...
records.


File format

There are multiple tar file formats, including historical and current ones. Two tar formats are codified in POSIX:
ustar The Utah Science Technology and Research Initiative (USTAR) is a technology-based economic development agency funded by the state of Utah. The organization works to develop ideas and research into marketable products and successful companies throug ...
and pax. Not codified but still in current use is the GNU tar format. A tar archive consists of a series of file objects, hence the popular term ''tarball'', referencing how a
tarball Tarball may refer to: * Tarball (computing), a type of archive file * Tarball (oil) A tarball is a blob of petroleum which has been weathered after floating in the ocean. Tarballs are an aquatic pollutant in most environments, although they can ...
collects objects of all kinds that stick to its surface. Each file object includes any file data, and is preceded by a 512-byte header record. The file data is written unaltered except that its length is rounded up to a multiple of 512 bytes. The original tar implementation did not care about the contents of the padding bytes, and left the buffer data unaltered, but most modern tar implementations fill the extra space with zeros. The end of an archive is marked by at least two consecutive zero-filled records. (The origin of tar's record size appears to be the 512-byte disk sectors used in the Version 7 Unix file system.) The final block of an archive is padded out to full length with zeros.


Header

The file header record contains
metadata Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive ...
about a file. To ensure portability across different architectures with different byte orderings, the information in the header record is encoded in
ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because ...
. Thus if all the files in an archive are ASCII text files, and have ASCII names, then the archive is essentially an ASCII text file (containing many NUL characters). The fields defined by the original Unix tar format are listed in the table below. The link indicator/file type table includes some modern extensions. When a field is unused it is filled with NUL bytes. The header uses 257 bytes, then is padded with NUL bytes to make it fill a 512 byte record. There is no "magic number" in the header, for file identification. Pre-POSIX.1-1988 (i.e. v7) tar header: The pre-POSIX.1-1988 Link indicator field can have the following values: Some pre-POSIX.1-1988 tar implementations indicated a directory by having a trailing
slash Slash may refer to: * Slash (punctuation), the "/" character Arts and entertainment Fictional characters * Slash (Marvel Comics) * Slash (''Teenage Mutant Ninja Turtles'') Music * Harry Slash & The Slashtones, an American rock band * Nash ...
(/) in the name. Numeric values are encoded in
octal The octal numeral system, or oct for short, is the radix, base-8 number system, and uses the Numerical digit, digits 0 to 7. This is to say that 10octal represents eight and 100octal represents sixty-four. However, English, like most languages, ...
numbers using ASCII digits, with leading zeroes. For historical reasons, a final NUL or
space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consi ...
character should also be used. Thus although there are 12 bytes reserved for storing the file size, only 11 octal digits can be stored. This gives a maximum file size of 8
gigabyte The gigabyte () is a multiple of the unit byte for digital information. The prefix '' giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB. This definit ...
s on archived files. To overcome this limitation, in 2001 star introduced a base-256 coding that is indicated by setting the high-order bit of the leftmost byte of a numeric field. GNU-tar and BSD-tar followed this idea. Additionally, versions of tar from before the first POSIX standard from 1988 pad the values with spaces instead of zeroes. The
checksum A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data ...
is calculated by taking the sum of the unsigned byte values of the header record with the eight checksum bytes taken to be ASCII spaces (decimal value 32). It is stored as a six digit octal number with leading zeroes followed by a NUL and then a space. Various implementations do not adhere to this format. In addition, some historic tar implementations treated bytes as signed. Implementations typically calculate the checksum both ways, and treat it as good if either the signed or unsigned sum matches the included checksum. Unix filesystems support multiple links (names) for the same file. If several such files appear in a tar archive, only the first one is archived as a normal file; the rest are archived as hard links, with the "name of linked file" field set to the first one's name. On extraction, such hard links should be recreated in the file system.


UStar format

Most modern tar programs read and write archives in the UStar (''Unix Standard TAR'') format, introduced by the POSIX IEEE P1003.1 standard from 1988. It introduced additional header fields. Older tar programs will ignore the extra information (possibly extracting partially named files), while newer programs will test for the presence of the "ustar" string to determine if the new format is in use. The UStar format allows for longer file names and stores additional information about each file. The maximum filename size is 256, but it is split among a preceding path "filename prefix" and the filename itself, so can be much less. The ''type flag'' field can have the following values: POSIX.1-1988 vendor specific extensions using link flag values 'A'–'Z' partially have a different meaning with different vendors and thus are seen as outdated and replaced by the POSIX.1-2001 extensions that also include a vendor tag. Type '7' (Contiguous file) is formally marked as reserved in the POSIX standard, but was meant to indicate files which ought to be contiguously allocated on disk. Few operating systems support creating such files explicitly, and hence most TAR programs do not support them, and will treat type 7 files as if they were type 0 (regular). An exception is older versions of GNU tar, when running on the MASSCOMP RTU (Real Time Unix) operating system, which supported an O_CTG flag to the open() function to request a contiguous file; however, that support was removed from GNU tar version 1.24 onwards.


POSIX.1-2001/pax

In 1997,
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
proposed a method for adding extensions to the tar format. This method was later accepted for the POSIX.1-2001 standard. This format is known as ''extended tar'' format or pax format. The new tar format allows users to add any type of vendor-tagged vendor-specific enhancements. The following tags are defined by the POSIX standard: * atime, mtime: all timestamps of a file in arbitrary resolution (most implementations use nanosecond granularity) * path: path names of unlimited length and character set coding * linkpath: symlink target names of unlimited length and character set coding * uname, gname: user and group names of unlimited length and character set coding * size: files with unlimited size (the historic tar format is 8 GB) * uid, gid: userid and groupid without size limitation (the historic tar format was is limited to a max. id of 2097151) * a character set definition for path names and user/group names (
UTF-8 UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''. UTF-8 is capable of e ...
) In 2001, the Star program became the first tar to support the new format. In 2004, GNU tar supported the new format, though it does not write it as its default output from the tar program yet. The pax format is designed so that all implementations able to read the UStar format will be able to read the pax format as well. The only exceptions are files that make use of extended features, such as longer file names. For compatibility, these are encoded in the tar files as special or type files, typically under a directory. A pax-supporting implementation would make use of the information, while non-supporting ones like
7-Zip 7-Zip is a free and open-source file archiver, a utility used to place groups of files within compressed containers known as "archives". It is developed by Igor Pavlov and was first released in 1999. 7-Zip has its own archive format called 7z, ...
would process them as additional files.


Uses


Command syntax

tar
options Option or Options may refer to: Computing *Option key, a key on Apple computer keyboards *Option type, a polymorphic data type in programming languages *Command-line option, an optional parameter to a command *OPTIONS, an HTTP request method ...
iles or directories which to add into archive Iles is a surname. Notable people with the surname include: *Albert Iles (1914–1979), English footballer *Alex Iles, American musician *Bob Iles (born 1955), English footballer *Bradley Iles (born 1983), New Zealand golfer *Brian Iles, American a ...
Basic options: * -c, --create — create a new archive; * -a, --auto-compress — additionally compress the archive with a compressor which will be automatically determined by the file name extension of the archive. If the archive's name ends with then use
gzip gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and i ...
, if then use xz, for
Zstandard Zstandard, commonly known by the name of its reference implementation zstd, is a lossless data compression algorithm developed by Yann Collet at Facebook. ''Zstd'' is the reference implementation in C. Version 1 of this implementation was r ...
etc.; * -r, --append — append files to the end of an archive; * -x, --extract, --get — extract files from an archive; * -f, --file — specify the archive's name; * -t, --list — show a list of files and folders in the archive; * -v, --verbose — show a list of processed files.


Basic usage

Create an archive file from the file and directory : $ tar -cvf archive.tar README.txt src Extract contents for the into the current directory: $ tar -xvf archive.tar Create an archive file from the file and directory and compress it with
gzip gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and i ...
: $ tar -cavf archive.tar.gz README.txt src Extract contents for the into the current directory: $ tar -xvf archive.tar.gz


Tarpipe

A tarpipe is the method of creating an archive on the
standard output In computer programming, standard streams are interconnected input and output communication channels between a computer program and its environment when it begins execution. The three input/output (I/O) connections are called standard input (stdin ...
file of the tar utility and piping it to another tar process on its standard input, working in another directory, where it is unpacked. This process copies an entire source directory tree including all special files, for example: $ tar cf - srcdir , tar x -C destdir


Software distribution

The tar format continues to be used extensively for
open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized so ...
software distribution. *NIX-distributions use it in various source- and binary-package distribution mechanisms, with most software
source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the ...
made available in compressed tar archives.


Limitations

The original tar format was created in the early days of Unix, and despite current widespread use, many of its design features are considered dated. Many older tar implementations do not record nor restore extended attributes (xattrs) or access-control lists (ACLs). In 2001, Star introduced support for ACLs and extended attributes, through its own tags for POSIX.1-2001 pax. Bsdtar uses the star extensions to support ACLs. More recent versions of GNU tar support Linux extended attributes, reimplementing star extensions. A number of extensions are reviewed in the filetype manual for BSD tar, tar(5). Other formats have been created to address the shortcomings of tar.


Tarbomb

A tarbomb, in hacker slang, is a tar file that contains many files that extract into the working directory. Such a tar file can create problems by overwriting files of the same name in the working directory, or mixing one project's files into another. It is at best an inconvenience to the user, who is obliged to identify and delete a number of files interspersed with the directory's other contents. Such behavior is considered bad etiquette on the part of the archive's creator. A related problem is the use of absolute paths or parent directory references when creating tar files. Files extracted from such archives will often be created in unusual locations outside the working directory and, like a tarbomb, have the potential to overwrite existing files. However, modern versions of FreeBSD and GNU tar do not create or extract absolute paths and parent-directory references by default, unless it is explicitly allowed with the flag or the option . The bsdtar program, which is also available on many operating systems and is the default tar utility on
Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lap ...
v10.6, also does not follow parent-directory references or symbolic links. If a user has only a very old tar available, which does not feature those security measures, these problems can be mitigated by first examining a tar file using the command tar tf archive.tar, which lists the contents and allows to exclude problematic files afterwards. These commands do not extract any files, but display the names of all files in the archive. If any are problematic, the user can create a new empty directory and extract the archive into it—or avoid the tar file entirely. Most graphical tools can display the contents of the archive before extracting them. Vim can open tar archives and display their contents.
GNU Emacs GNU Emacs is a free software text editor. It was created by GNU Project founder Richard Stallman, based on the Emacs editor developed for Unix operating systems. GNU Emacs has been a central component of the GNU project and a flagship project ...
is also able to open a tar archive and display its contents in a dired buffer.


Random access

The tar format was designed without a centralized index or table of content for files and their properties for streaming to tape backup devices. The archive must be read sequentially to list or extract files. For large tar archives, this causes a performance penalty, making tar archives unsuitable for situations that often require random access to individual files.


Duplicates

Another issue with tar format is that it allows several (possibly different) files in archive to have identical path and filename. When extracting such archive, usually the latter version of a file overwrites the former. This can create a non-explicit (unobvious) tarbomb, which technically does not contain files with absolute paths or referring parent directories, but still causes overwriting files outside current directory (for example, archive may contain two files with the same path and filename, first of which is a
symlink In computing, a symbolic link (also symlink or soft link) is a file whose purpose is to point to a file or directory (called the "target") by specifying a path thereto. Symbolic links are supported by POSIX and by most Unix-like operating syst ...
to some location outside current directory, and second of which is a regular file; then extracting such archive on some tar implementations may cause writing to the location pointed to by the symlink).


Key implementations

Historically, many systems have implemented tar, and many general file archivers have at least partial support for tar (often using one of the implementations below). The history of tar is a story of incompatibilities, known as the "tar wars". Most tar implementations can also read and create
cpio cpio is a general file archiver utility and its associated file format. It is primarily installed on Unix-like computer operating systems. The software utility was originally intended as a tape archiving program as part of the Programmer's Work ...
and pax (the latter actually is a ''tar''-format with
POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming in ...
-2001-extensions). Key implementations in order of origin: * Solaris tar, based on the original Unix V7 tar and comes as the default on the Solaris operating system *
GNU GNU () is an extensive collection of free software (383 packages as of January 2022), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operat ...
tar is the default on most
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
distributions. It is based on the public domain implementation pdtar which started in 1987. Recent versions can use various formats, including ustar, pax, GNU and v7 formats. *
FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...
tar (also BSD tar) has become the default tar on most
Berkeley Software Distribution The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Be ...
-based operating systems including
Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lap ...
. The core functionality is available as libarchive for inclusion in other applications. This implementation automatically detects the format of the file and can extract from tar, pax, cpio, zip, rar, ar, xar, rpm and ISO 9660 cdrom images. It also comes with a functionally equivalent cpio command-line interface. * Schily tar, better known as star, is historically significant as some of its extensions were quite popular. First published in April 1997, its developer has stated that he began development in 1982. * Python tarfile module supports multiple tar formats, including ustar, pax and gnu; it can read but not create V7 format and the SunOS tar extended format; pax is the default format for creation of archives. Available since 2003. Additionally, most pax and
cpio cpio is a general file archiver utility and its associated file format. It is primarily installed on Unix-like computer operating systems. The software utility was originally intended as a tape archiving program as part of the Programmer's Work ...
implementations can read and create multiple types of tar files.


Suffixes for compressed files

''tar'' archive files usually have the file suffix ''.tar'' (e.g. ''somefile.tar''). A tar archive file contains uncompressed byte streams of the files which it contains. To achieve archive compression, a variety of
compression Compression may refer to: Physical science *Compression (physics), size reduction due to forces *Compression member, a structural element such as a column *Compressibility, susceptibility to compression * Gas compression *Compression ratio, of a ...
programs are available, such as
gzip gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and i ...
, bzip2, xz, lzip, lzma,
zstd Zstandard, commonly known by the name of its reference implementation zstd, is a lossless data compression algorithm developed by Yann Collet at Facebook. ''Zstd'' is the reference implementation in C. Version 1 of this implementation was re ...
, or
compress compress is a Unix shell compression program based on the LZW compression algorithm. Compared to more modern compression utilities such as gzip and bzip2, compress performs faster and with less memory usage, at the cost of a significantly lo ...
, which compress the entire tar archive. Typically, the compressed form of the archive receives a filename by appending the format-specific compressor suffix to the archive file name. For example, a tar archive ''archive.tar'', is named ''archive.tar.gz'', when it is compressed by gzip. Popular tar programs like the BSD and
GNU GNU () is an extensive collection of free software (383 packages as of January 2022), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operat ...
versions of tar support the
command line options A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive command (computing), commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invokin ...
''Z'' (compress), ''z'' (gzip), and ''j'' (bzip2) to compress or decompress the archive file upon creation or unpacking. Relatively recent additions include ''--lzma'' ( LZMA), ''--lzop'' (
lzop lzop is a free software file compression tool which implements the LZO algorithm and is licensed under the GPL. Aimed at being very fast, lzop produces files slightly larger than gzip while only requiring a tenth of the CPU use and only slight ...
), ''--xz'' or ''J'' ( xz), ''--lzip'' (lzip), and ''--zstd''. The decompression of these formats is handled automatically if supported filename extensions are used, and compression is handled automatically using the same filename extensions if the option ''--auto-compress'' (short form ''-a'') is passed to an applicable version of GNU tar. BSD tar detects an even wider range of compressors (
lrzip rzip is a huge-scale data compression computer program designed around initial LZ77-style string matching on a 900 MB dictionary window, followed by bzip2-based Burrows–Wheeler transform and entropy coding ( Huffman) on 900 kB outp ...
, lz4), using not the filename but the data within. Unrecognized formats are to be manually compressed or decompressed by piping.
MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few o ...
's
8.3 filename An 8.3 filename (also called a short filename or SFN) is a filename convention used by old versions of DOS and versions of Microsoft Windows prior to Windows 95 and Windows NT 3.5. It is also used in modern Microsoft operating systems as an altern ...
limitations resulted in additional conventions for naming compressed tar archives. However, this practice has declined with FAT now offering
long filename Long filename (LFN) support is Microsoft's backward-compatible extension of the 8.3 filename (short filename) naming scheme used in DOS. Long filenames can be more descriptive, including longer filename extensions such as .jpeg, .tiff, .html, ...
s.


See also

*
Comparison of file archivers The following tables compare general and technical information for a number of file archivers. Please see the individual products' articles for further information. They are neither all-inclusive nor are some entries necessarily up to date. Unles ...
*
Comparison of archive formats This is a list of file formats used by file archiver, archivers and data compression, compressors used to create archive files. Archiving only Compression only Archiving and compression Data recovery Comparison Containers and compression ...
*
List of archive formats This is a list of file formats used by archivers and compressors used to create archive files. Archiving only Compression only Archiving and compression Data recovery Comparison Containers and compression Notes While the original ...
*
List of Unix commands This is a list of Unix commands as specified by IEEE Std 1003.1-2008, which is part of the Single UNIX Specification (SUS). These commands can be found on Unix operating systems and most Unix-like operating systems. List See also * List of G ...


References


External links


X/Open CAE Specification Commands and Utilities Issue 4, Version 2
(pdf), 1994, opengroup.org – indicates tar as to be withdrawn

in The Single UNIX ® Specification, Version 2, 1997, opengroup.org – indicates applications should migrate to pax utility

in The Open Group Base Specifications Issue 6, 2004 Edition, opengroup.org – indicates tar as removed * – specifies the ustar and pax file formats * * – manual from
GNU GNU () is an extensive collection of free software (383 packages as of January 2022), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operat ...
* * * * * *
TAR - Windows CMD - SS64.com
{{DEFAULTSORT:Tar (File Format) Archive formats Free backup software GNU Project software Unix archivers and compression-related utilities Plan 9 commands IBM i Qshell commands