pax.1 (2010 09)

p
pax(1) pax(1)
linkname The linkname is the pathname of the target of a symbolic or hard link. It is limited to 100
characters. If the name does not fit in the space provided,
pax shall notify the user of the
error, and shall not attempt to store the link on the medium.
devmajor,devminor
When the typeflag field contains ’3’ or ’4’ the
devmajor and devminor fields shall
contain the major and minor numbers of the device respectively.
chksum The octal value of the simple sum of all bytes in the header logical record. Each bytes in the
header shall be treated as an unsigned value. When calculating the checksum, the
chksum
field is treated as if it were all spaces.
magic The magic field is the specification that this archive was output in this archive format. If this
field contains
ustar (the five characters from the ISO/IEC 646:1991 standard IRV shown
followed by NULL), the uname and gname fields shall contain the ISO/IEC 646:1991 stan-
dard IRV representation of the owner and group of the file, respectively. When the file is
restored by a privileged, protection-preserving version of the utility, the user and group
databases shall be scanned for these names. If found, the user and group IDs contained
within these files shall be used rather than the values contained within the uid and gid
fields.
version The version field is two bytes containing the characters "00" (zero-zero).
pax Interchange Format
A
pax archive tape or file produced in the -x pax format shall contain a series of blocks. The physical
layout of the archive shall be identical to the ustar format described in ustar Interchange Format. Each
file archived shall be represented by the following sequence:
1. An optional header block with extended header records. This header is of the form described in pax
Header Block with a
typeflag value of x or g. The extended header records, described in pax
Extended Header shall be included as the data for this header block.
2. A header block that describes the file. Any fields in the preceding optional extended header shall
override the associated fields in this header block for this file.
3. Zero or more blocks that contain the contents of the file.
At the end of the archive file there shall be two 512-byte blocks filled with binary zeros, interpreted as an
end-of-archive indicator.
pax Header Block
The
pax header block shall be identical to the ustar header block described in ustar Interchange For-
mat except that two additional typeflag values are defined:
x Represents extended header records for the following file in the archive (which shall have its
own ustar header block). The format of these extended header records shall be as
described in the pax Extended Header section of this manpage.
g Represents global extended header records for the following files in the archive. The format
of these extended header records shall be as described in pax Extended Header . Each value
shall affect all subsequent files that do not override that value in their own extended header
record and until another global extended header record is reached that provides another
value for the same field. The typeflag g global headers should not be used with inter-
change media that could suffer partial data loss in transporting the archive.
For both of these types, the size field shall be the size of the extended header records in bytes. The other
fields in the header block are not meaningful to this version of the pax utility.
A further difference from the
ustar header block is that data blocks for files of typeflag 1 (the digit one)
(hard link) may be included, which means that the size field may be greater than zero. Archives created
by pax -o linkdata shall include these data blocks with the hard links.
pax Extended Header
A
pax extended header contains values that are inappropriate for the ustar header block because of
limitations in that format: fields representing file attributes not described in the ustar header, and
fields whose format or length do not fit the requirements of the ustar header. The values in an
extended header add attributes to the following file (or files; see the description of the typeflag g
header block) or override values in the following header block(s), as indicated in the following list of key-
words.
10 Hewlett-Packard Company − 10 − HP-UX 11i Version 3: September 2010