diff options
Diffstat (limited to 'lib/libarchive/tar.5')
| -rw-r--r-- | lib/libarchive/tar.5 | 831 |
1 files changed, 0 insertions, 831 deletions
diff --git a/lib/libarchive/tar.5 b/lib/libarchive/tar.5 deleted file mode 100644 index c2c594b..0000000 --- a/lib/libarchive/tar.5 +++ /dev/null @@ -1,831 +0,0 @@ -.\" Copyright (c) 2003-2009 Tim Kientzle -.\" All rights reserved. -.\" -.\" Redistribution and use in source and binary forms, with or without -.\" modification, are permitted provided that the following conditions -.\" are met: -.\" 1. Redistributions of source code must retain the above copyright -.\" notice, this list of conditions and the following disclaimer. -.\" 2. Redistributions in binary form must reproduce the above copyright -.\" notice, this list of conditions and the following disclaimer in the -.\" documentation and/or other materials provided with the distribution. -.\" -.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND -.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE -.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE -.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE -.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL -.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS -.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) -.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY -.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF -.\" SUCH DAMAGE. -.\" -.\" $FreeBSD$ -.\" -.Dd December 27, 2009 -.Dt TAR 5 -.Os -.Sh NAME -.Nm tar -.Nd format of tape archive files -.Sh DESCRIPTION -The -.Nm -archive format collects any number of files, directories, and other -file system objects (symbolic links, device nodes, etc.) into a single -stream of bytes. -The format was originally designed to be used with -tape drives that operate with fixed-size blocks, but is widely used as -a general packaging mechanism. -.Ss General Format -A -.Nm -archive consists of a series of 512-byte records. -Each file system object requires a header record which stores basic metadata -(pathname, owner, permissions, etc.) and zero or more records containing any -file data. -The end of the archive is indicated by two records consisting -entirely of zero bytes. -.Pp -For compatibility with tape drives that use fixed block sizes, -programs that read or write tar files always read or write a fixed -number of records with each I/O operation. -These -.Dq blocks -are always a multiple of the record size. -The maximum block size supported by early -implementations was 10240 bytes or 20 records. -This is still the default for most implementations -although block sizes of 1MiB (2048 records) or larger are -commonly used with modern high-speed tape drives. -(Note: the terms -.Dq block -and -.Dq record -here are not entirely standard; this document follows the -convention established by John Gilmore in documenting -.Nm pdtar . ) -.Ss Old-Style Archive Format -The original tar archive format has been extended many times to -include additional information that various implementors found -necessary. -This section describes the variant implemented by the tar command -included in -.At v7 , -which seems to be the earliest widely-used version of the tar program. -.Pp -The header record for an old-style -.Nm -archive consists of the following: -.Bd -literal -offset indent -struct header_old_tar { - char name[100]; - char mode[8]; - char uid[8]; - char gid[8]; - char size[12]; - char mtime[12]; - char checksum[8]; - char linkflag[1]; - char linkname[100]; - char pad[255]; -}; -.Ed -All unused bytes in the header record are filled with nulls. -.Bl -tag -width indent -.It Va name -Pathname, stored as a null-terminated string. -Early tar implementations only stored regular files (including -hardlinks to those files). -One common early convention used a trailing "/" character to indicate -a directory name, allowing directory permissions and owner information -to be archived and restored. -.It Va mode -File mode, stored as an octal number in ASCII. -.It Va uid , Va gid -User id and group id of owner, as octal numbers in ASCII. -.It Va size -Size of file, as octal number in ASCII. -For regular files only, this indicates the amount of data -that follows the header. -In particular, this field was ignored by early tar implementations -when extracting hardlinks. -Modern writers should always store a zero length for hardlink entries. -.It Va mtime -Modification time of file, as an octal number in ASCII. -This indicates the number of seconds since the start of the epoch, -00:00:00 UTC January 1, 1970. -Note that negative values should be avoided -here, as they are handled inconsistently. -.It Va checksum -Header checksum, stored as an octal number in ASCII. -To compute the checksum, set the checksum field to all spaces, -then sum all bytes in the header using unsigned arithmetic. -This field should be stored as six octal digits followed by a null and a space -character. -Note that many early implementations of tar used signed arithmetic -for the checksum field, which can cause interoperability problems -when transferring archives between systems. -Modern robust readers compute the checksum both ways and accept the -header if either computation matches. -.It Va linkflag , Va linkname -In order to preserve hardlinks and conserve tape, a file -with multiple links is only written to the archive the first -time it is encountered. -The next time it is encountered, the -.Va linkflag -is set to an ASCII -.Sq 1 -and the -.Va linkname -field holds the first name under which this file appears. -(Note that regular files have a null value in the -.Va linkflag -field.) -.El -.Pp -Early tar implementations varied in how they terminated these fields. -The tar command in -.At v7 -used the following conventions (this is also documented in early BSD manpages): -the pathname must be null-terminated; -the mode, uid, and gid fields must end in a space and a null byte; -the size and mtime fields must end in a space; -the checksum is terminated by a null and a space. -Early implementations filled the numeric fields with leading spaces. -This seems to have been common practice until the -.St -p1003.1-88 -standard was released. -For best portability, modern implementations should fill the numeric -fields with leading zeros. -.Ss Pre-POSIX Archives -An early draft of -.St -p1003.1-88 -served as the basis for John Gilmore's -.Nm pdtar -program and many system implementations from the late 1980s -and early 1990s. -These archives generally follow the POSIX ustar -format described below with the following variations: -.Bl -bullet -compact -width indent -.It -The magic value is -.Dq ustar\ \& -(note the following space). -The version field contains a space character followed by a null. -.It -The numeric fields are generally filled with leading spaces -(not leading zeros as recommended in the final standard). -.It -The prefix field is often not used, limiting pathnames to -the 100 characters of old-style archives. -.El -.Ss POSIX ustar Archives -.St -p1003.1-88 -defined a standard tar file format to be read and written -by compliant implementations of -.Xr tar 1 . -This format is often called the -.Dq ustar -format, after the magic value used -in the header. -(The name is an acronym for -.Dq Unix Standard TAR . ) -It extends the historic format with new fields: -.Bd -literal -offset indent -struct header_posix_ustar { - char name[100]; - char mode[8]; - char uid[8]; - char gid[8]; - char size[12]; - char mtime[12]; - char checksum[8]; - char typeflag[1]; - char linkname[100]; - char magic[6]; - char version[2]; - char uname[32]; - char gname[32]; - char devmajor[8]; - char devminor[8]; - char prefix[155]; - char pad[12]; -}; -.Ed -.Bl -tag -width indent -.It Va typeflag -Type of entry. -POSIX extended the earlier -.Va linkflag -field with several new type values: -.Bl -tag -width indent -compact -.It Dq 0 -Regular file. -NUL should be treated as a synonym, for compatibility purposes. -.It Dq 1 -Hard link. -.It Dq 2 -Symbolic link. -.It Dq 3 -Character device node. -.It Dq 4 -Block device node. -.It Dq 5 -Directory. -.It Dq 6 -FIFO node. -.It Dq 7 -Reserved. -.It Other -A POSIX-compliant implementation must treat any unrecognized typeflag value -as a regular file. -In particular, writers should ensure that all entries -have a valid filename so that they can be restored by readers that do not -support the corresponding extension. -Uppercase letters "A" through "Z" are reserved for custom extensions. -Note that sockets and whiteout entries are not archivable. -.El -It is worth noting that the -.Va size -field, in particular, has different meanings depending on the type. -For regular files, of course, it indicates the amount of data -following the header. -For directories, it may be used to indicate the total size of all -files in the directory, for use by operating systems that pre-allocate -directory space. -For all other types, it should be set to zero by writers and ignored -by readers. -.It Va magic -Contains the magic value -.Dq ustar -followed by a NUL byte to indicate that this is a POSIX standard archive. -Full compliance requires the uname and gname fields be properly set. -.It Va version -Version. -This should be -.Dq 00 -(two copies of the ASCII digit zero) for POSIX standard archives. -.It Va uname , Va gname -User and group names, as null-terminated ASCII strings. -These should be used in preference to the uid/gid values -when they are set and the corresponding names exist on -the system. -.It Va devmajor , Va devminor -Major and minor numbers for character device or block device entry. -.It Va name , Va prefix -If the pathname is too long to fit in the 100 bytes provided by the standard -format, it can be split at any -.Pa / -character with the first portion going into the prefix field. -If the prefix field is not empty, the reader will prepend -the prefix value and a -.Pa / -character to the regular name field to obtain the full pathname. -The standard does not require a trailing -.Pa / -character on directory names, though most implementations still -include this for compatibility reasons. -.El -.Pp -Note that all unused bytes must be set to -.Dv NUL . -.Pp -Field termination is specified slightly differently by POSIX -than by previous implementations. -The -.Va magic , -.Va uname , -and -.Va gname -fields must have a trailing -.Dv NUL . -The -.Va pathname , -.Va linkname , -and -.Va prefix -fields must have a trailing -.Dv NUL -unless they fill the entire field. -(In particular, it is possible to store a 256-character pathname if it -happens to have a -.Pa / -as the 156th character.) -POSIX requires numeric fields to be zero-padded in the front, and requires -them to be terminated with either space or -.Dv NUL -characters. -.Pp -Currently, most tar implementations comply with the ustar -format, occasionally extending it by adding new fields to the -blank area at the end of the header record. -.Ss Pax Interchange Format -There are many attributes that cannot be portably stored in a -POSIX ustar archive. -.St -p1003.1-2001 -defined a -.Dq pax interchange format -that uses two new types of entries to hold text-formatted -metadata that applies to following entries. -Note that a pax interchange format archive is a ustar archive in every -respect. -The new data is stored in ustar-compatible archive entries that use the -.Dq x -or -.Dq g -typeflag. -In particular, older implementations that do not fully support these -extensions will extract the metadata into regular files, where the -metadata can be examined as necessary. -.Pp -An entry in a pax interchange format archive consists of one or -two standard ustar entries, each with its own header and data. -The first optional entry stores the extended attributes -for the following entry. -This optional first entry has an "x" typeflag and a size field that -indicates the total size of the extended attributes. -The extended attributes themselves are stored as a series of text-format -lines encoded in the portable UTF-8 encoding. -Each line consists of a decimal number, a space, a key string, an equals -sign, a value string, and a new line. -The decimal number indicates the length of the entire line, including the -initial length field and the trailing newline. -An example of such a field is: -.Dl 25 ctime=1084839148.1212\en -Keys in all lowercase are standard keys. -Vendors can add their own keys by prefixing them with an all uppercase -vendor name and a period. -Note that, unlike the historic header, numeric values are stored using -decimal, not octal. -A description of some common keys follows: -.Bl -tag -width indent -.It Cm atime , Cm ctime , Cm mtime -File access, inode change, and modification times. -These fields can be negative or include a decimal point and a fractional value. -.It Cm uname , Cm uid , Cm gname , Cm gid -User name, group name, and numeric UID and GID values. -The user name and group name stored here are encoded in UTF8 -and can thus include non-ASCII characters. -The UID and GID fields can be of arbitrary length. -.It Cm linkpath -The full path of the linked-to file. -Note that this is encoded in UTF8 and can thus include non-ASCII characters. -.It Cm path -The full pathname of the entry. -Note that this is encoded in UTF8 and can thus include non-ASCII characters. -.It Cm realtime.* , Cm security.* -These keys are reserved and may be used for future standardization. -.It Cm size -The size of the file. -Note that there is no length limit on this field, allowing conforming -archives to store files much larger than the historic 8GB limit. -.It Cm SCHILY.* -Vendor-specific attributes used by Joerg Schilling's -.Nm star -implementation. -.It Cm SCHILY.acl.access , Cm SCHILY.acl.default -Stores the access and default ACLs as textual strings in a format -that is an extension of the format specified by POSIX.1e draft 17. -In particular, each user or group access specification can include a fourth -colon-separated field with the numeric UID or GID. -This allows ACLs to be restored on systems that may not have complete -user or group information available (such as when NIS/YP or LDAP services -are temporarily unavailable). -.It Cm SCHILY.devminor , Cm SCHILY.devmajor -The full minor and major numbers for device nodes. -.It Cm SCHILY.fflags -The file flags. -.It Cm SCHILY.realsize -The full size of the file on disk. -XXX explain? XXX -.It Cm SCHILY.dev, Cm SCHILY.ino , Cm SCHILY.nlinks -The device number, inode number, and link count for the entry. -In particular, note that a pax interchange format archive using Joerg -Schilling's -.Cm SCHILY.* -extensions can store all of the data from -.Va struct stat . -.It Cm LIBARCHIVE.xattr. Ns Ar namespace Ns . Ns Ar key -Libarchive stores POSIX.1e-style extended attributes using -keys of this form. -The -.Ar key -value is URL-encoded: -All non-ASCII characters and the two special characters -.Dq = -and -.Dq % -are encoded as -.Dq % -followed by two uppercase hexadecimal digits. -The value of this key is the extended attribute value -encoded in base 64. -XXX Detail the base-64 format here XXX -.It Cm VENDOR.* -XXX document other vendor-specific extensions XXX -.El -.Pp -Any values stored in an extended attribute override the corresponding -values in the regular tar header. -Note that compliant readers should ignore the regular fields when they -are overridden. -This is important, as existing archivers are known to store non-compliant -values in the standard header fields in this situation. -There are no limits on length for any of these fields. -In particular, numeric fields can be arbitrarily large. -All text fields are encoded in UTF8. -Compliant writers should store only portable 7-bit ASCII characters in -the standard ustar header and use extended -attributes whenever a text value contains non-ASCII characters. -.Pp -In addition to the -.Cm x -entry described above, the pax interchange format -also supports a -.Cm g -entry. -The -.Cm g -entry is identical in format, but specifies attributes that serve as -defaults for all subsequent archive entries. -The -.Cm g -entry is not widely used. -.Pp -Besides the new -.Cm x -and -.Cm g -entries, the pax interchange format has a few other minor variations -from the earlier ustar format. -The most troubling one is that hardlinks are permitted to have -data following them. -This allows readers to restore any hardlink to a file without -having to rewind the archive to find an earlier entry. -However, it creates complications for robust readers, as it is no longer -clear whether or not they should ignore the size field for hardlink entries. -.Ss GNU Tar Archives -The GNU tar program started with a pre-POSIX format similar to that -described earlier and has extended it using several different mechanisms: -It added new fields to the empty space in the header (some of which was later -used by POSIX for conflicting purposes); -it allowed the header to be continued over multiple records; -and it defined new entries that modify following entries -(similar in principle to the -.Cm x -entry described above, but each GNU special entry is single-purpose, -unlike the general-purpose -.Cm x -entry). -As a result, GNU tar archives are not POSIX compatible, although -more lenient POSIX-compliant readers can successfully extract most -GNU tar archives. -.Bd -literal -offset indent -struct header_gnu_tar { - char name[100]; - char mode[8]; - char uid[8]; - char gid[8]; - char size[12]; - char mtime[12]; - char checksum[8]; - char typeflag[1]; - char linkname[100]; - char magic[6]; - char version[2]; - char uname[32]; - char gname[32]; - char devmajor[8]; - char devminor[8]; - char atime[12]; - char ctime[12]; - char offset[12]; - char longnames[4]; - char unused[1]; - struct { - char offset[12]; - char numbytes[12]; - } sparse[4]; - char isextended[1]; - char realsize[12]; - char pad[17]; -}; -.Ed -.Bl -tag -width indent -.It Va typeflag -GNU tar uses the following special entry types, in addition to -those defined by POSIX: -.Bl -tag -width indent -.It "7" -GNU tar treats type "7" records identically to type "0" records, -except on one obscure RTOS where they are used to indicate the -pre-allocation of a contiguous file on disk. -.It "D" -This indicates a directory entry. -Unlike the POSIX-standard "5" -typeflag, the header is followed by data records listing the names -of files in this directory. -Each name is preceded by an ASCII "Y" -if the file is stored in this archive or "N" if the file is not -stored in this archive. -Each name is terminated with a null, and -an extra null marks the end of the name list. -The purpose of this -entry is to support incremental backups; a program restoring from -such an archive may wish to delete files on disk that did not exist -in the directory when the archive was made. -.Pp -Note that the "D" typeflag specifically violates POSIX, which requires -that unrecognized typeflags be restored as normal files. -In this case, restoring the "D" entry as a file could interfere -with subsequent creation of the like-named directory. -.It "K" -The data for this entry is a long linkname for the following regular entry. -.It "L" -The data for this entry is a long pathname for the following regular entry. -.It "M" -This is a continuation of the last file on the previous volume. -GNU multi-volume archives guarantee that each volume begins with a valid -entry header. -To ensure this, a file may be split, with part stored at the end of one volume, -and part stored at the beginning of the next volume. -The "M" typeflag indicates that this entry continues an existing file. -Such entries can only occur as the first or second entry -in an archive (the latter only if the first entry is a volume label). -The -.Va size -field specifies the size of this entry. -The -.Va offset -field at bytes 369-380 specifies the offset where this file fragment -begins. -The -.Va realsize -field specifies the total size of the file (which must equal -.Va size -plus -.Va offset ) . -When extracting, GNU tar checks that the header file name is the one it is -expecting, that the header offset is in the correct sequence, and that -the sum of offset and size is equal to realsize. -.It "N" -Type "N" records are no longer generated by GNU tar. -They contained a -list of files to be renamed or symlinked after extraction; this was -originally used to support long names. -The contents of this record -are a text description of the operations to be done, in the form -.Dq Rename %s to %s\en -or -.Dq Symlink %s to %s\en ; -in either case, both -filenames are escaped using K&R C syntax. -Due to security concerns, "N" records are now generally ignored -when reading archives. -.It "S" -This is a -.Dq sparse -regular file. -Sparse files are stored as a series of fragments. -The header contains a list of fragment offset/length pairs. -If more than four such entries are required, the header is -extended as necessary with -.Dq extra -header extensions (an older format that is no longer used), or -.Dq sparse -extensions. -.It "V" -The -.Va name -field should be interpreted as a tape/volume header name. -This entry should generally be ignored on extraction. -.El -.It Va magic -The magic field holds the five characters -.Dq ustar -followed by a space. -Note that POSIX ustar archives have a trailing null. -.It Va version -The version field holds a space character followed by a null. -Note that POSIX ustar archives use two copies of the ASCII digit -.Dq 0 . -.It Va atime , Va ctime -The time the file was last accessed and the time of -last change of file information, stored in octal as with -.Va mtime . -.It Va longnames -This field is apparently no longer used. -.It Sparse Va offset / Va numbytes -Each such structure specifies a single fragment of a sparse -file. -The two fields store values as octal numbers. -The fragments are each padded to a multiple of 512 bytes -in the archive. -On extraction, the list of fragments is collected from the -header (including any extension headers), and the data -is then read and written to the file at appropriate offsets. -.It Va isextended -If this is set to non-zero, the header will be followed by additional -.Dq sparse header -records. -Each such record contains information about as many as 21 additional -sparse blocks as shown here: -.Bd -literal -offset indent -struct gnu_sparse_header { - struct { - char offset[12]; - char numbytes[12]; - } sparse[21]; - char isextended[1]; - char padding[7]; -}; -.Ed -.It Va realsize -A binary representation of the file's complete size, with a much larger range -than the POSIX file size. -In particular, with -.Cm M -type files, the current entry is only a portion of the file. -In that case, the POSIX size field will indicate the size of this -entry; the -.Va realsize -field will indicate the total size of the file. -.El -.Ss GNU tar pax archives -GNU tar 1.14 (XXX check this XXX) and later will write -pax interchange format archives when you specify the -.Fl -posix -flag. -This format uses custom keywords to store sparse file information. -There have been three iterations of this support, referred to -as -.Dq 0.0 , -.Dq 0.1 , -and -.Dq 1.0 . -.Bl -tag -width indent -.It Cm GNU.sparse.numblocks , Cm GNU.sparse.offset , Cm GNU.sparse.numbytes , Cm GNU.sparse.size -The -.Dq 0.0 -format used an initial -.Cm GNU.sparse.numblocks -attribute to indicate the number of blocks in the file, a pair of -.Cm GNU.sparse.offset -and -.Cm GNU.sparse.numbytes -to indicate the offset and size of each block, -and a single -.Cm GNU.sparse.size -to indicate the full size of the file. -This is not the same as the size in the tar header because the -latter value does not include the size of any holes. -This format required that the order of attributes be preserved and -relied on readers accepting multiple appearances of the same attribute -names, which is not officially permitted by the standards. -.It Cm GNU.sparse.map -The -.Dq 0.1 -format used a single attribute that stored a comma-separated -list of decimal numbers. -Each pair of numbers indicated the offset and size, respectively, -of a block of data. -This does not work well if the archive is extracted by an archiver -that does not recognize this extension, since many pax implementations -simply discard unrecognized attributes. -.It Cm GNU.sparse.major , Cm GNU.sparse.minor , Cm GNU.sparse.name , Cm GNU.sparse.realsize -The -.Dq 1.0 -format stores the sparse block map in one or more 512-byte blocks -prepended to the file data in the entry body. -The pax attributes indicate the existence of this map -(via the -.Cm GNU.sparse.major -and -.Cm GNU.sparse.minor -fields) -and the full size of the file. -The -.Cm GNU.sparse.name -holds the true name of the file. -To avoid confusion, the name stored in the regular tar header -is a modified name so that extraction errors will be apparent -to users. -.El -.Ss Solaris Tar -XXX More Details Needed XXX -.Pp -Solaris tar (beginning with SunOS XXX 5.7 ?? XXX) supports an -.Dq extended -format that is fundamentally similar to pax interchange format, -with the following differences: -.Bl -bullet -compact -width indent -.It -Extended attributes are stored in an entry whose type is -.Cm X , -not -.Cm x , -as used by pax interchange format. -The detailed format of this entry appears to be the same -as detailed above for the -.Cm x -entry. -.It -An additional -.Cm A -entry is used to store an ACL for the following regular entry. -The body of this entry contains a seven-digit octal number -followed by a zero byte, followed by the -textual ACL description. -The octal value is the number of ACL entries -plus a constant that indicates the ACL type: 01000000 -for POSIX.1e ACLs and 03000000 for NFSv4 ACLs. -.El -.Ss AIX Tar -XXX More details needed XXX -.Ss Mac OS X Tar -The tar distributed with Apple's Mac OS X stores most regular files -as two separate entries in the tar archive. -The two entries have the same name except that the first -one has -.Dq ._ -added to the beginning of the name. -This first entry stores the -.Dq resource fork -with additional attributes for the file. -The Mac OS X -.Fn CopyFile -API is used to separate a file on disk into separate -resource and data streams and to reassemble those separate -streams when the file is restored to disk. -.Ss Other Extensions -One obvious extension to increase the size of files is to -eliminate the terminating characters from the various -numeric fields. -For example, the standard only allows the size field to contain -11 octal digits, reserving the twelfth byte for a trailing -NUL character. -Allowing 12 octal digits allows file sizes up to 64 GB. -.Pp -Another extension, utilized by GNU tar, star, and other newer -.Nm -implementations, permits binary numbers in the standard numeric fields. -This is flagged by setting the high bit of the first byte. -This permits 95-bit values for the length and time fields -and 63-bit values for the uid, gid, and device numbers. -GNU tar supports this extension for the -length, mtime, ctime, and atime fields. -Joerg Schilling's star program supports this extension for -all numeric fields. -Note that this extension is largely obsoleted by the extended attribute -record provided by the pax interchange format. -.Pp -Another early GNU extension allowed base-64 values rather than octal. -This extension was short-lived and is no longer supported by any -implementation. -.Sh SEE ALSO -.Xr ar 1 , -.Xr pax 1 , -.Xr tar 1 -.Sh STANDARDS -The -.Nm tar -utility is no longer a part of POSIX or the Single Unix Standard. -It last appeared in -.St -susv2 . -It has been supplanted in subsequent standards by -.Xr pax 1 . -The ustar format is currently part of the specification for the -.Xr pax 1 -utility. -The pax interchange file format is new with -.St -p1003.1-2001 . -.Sh HISTORY -A -.Nm tar -command appeared in Seventh Edition Unix, which was released in January, 1979. -It replaced the -.Nm tp -program from Fourth Edition Unix which in turn replaced the -.Nm tap -program from First Edition Unix. -John Gilmore's -.Nm pdtar -public-domain implementation (circa 1987) was highly influential -and formed the basis of -.Nm GNU tar -(circa 1988). -Joerg Shilling's -.Nm star -archiver is another open-source (GPL) archiver (originally developed -circa 1985) which features complete support for pax interchange -format. -.Pp -This documentation was written as part of the -.Nm libarchive -and -.Nm bsdtar -project by -.An Tim Kientzle Aq kientzle@FreeBSD.org . |
