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SPAX(1L)                    Schily's USER COMMANDS                    SPAX(1L)

NAME
       pax - portable archive interchange

SYNOPSIS
       spax        [other options]   [-cdnv]   [-H|-L]   [-f archive]  [-o op-
              tions]...  [-s replstr]...  [pattern...]

       spax   -r   [other options]  [-cdiknuv]  [-H|-L]  [-f archive]  [-o op-
              tions]...  [-p string]...  [-s replstr]...  [pattern...]

       spax   -w   [other options]   [-dituvX]   [-H|-L]  [-b blocksize]  [-a]
              [-f archive]   [-o options]...    [-s replstr]...    [-x format]
              [file...]

       spax   -r -w[other options]    [-diklntuvX]   [-H|-L]   [-o options]...
              [-p string]...  [-s replstr]...  [file...] directory

DESCRIPTION
       The pax utility shall read, write, and write lists of  the  members  of
       archive files and copy directory hierarchies. A variety of archive for-
       mats shall be supported; see the -x format option.

       The action to be taken depends on the presence of the  -r  and  -w  op-
       tions.  The  four combinations of -r and -w are referred to as the four
       modes of operation: list, read, write, and  copy  modes,  corresponding
       respectively to the four forms shown in the SYNOPSIS section.

       list   In  list  mode (when neither -r nor -w are specified), pax shall
              write the names of the members of the archive file read from the
              standard  input, with pathnames matching the specified patterns,
              to standard output. If a named file is of  type  directory,  the
              file hierarchy rooted at that file shall be listed as well.

       read   In  read  mode  (when -r is specified, but -w is not), pax shall
              extract the members of the archive file read from  the  standard
              input,  with  pathnames  matching the specified patterns.  If an
              extracted file is of type directory, the file  hierarchy  rooted
              at  that  file  shall  be extracted as well. The extracted files
              shall be created performing pathname resolution with the  direc-
              tory in which pax was invoked as the current working directory.

              If  an attempt is made to extract a directory when the directory
              already exists, this shall not be considered an error. If an at-
              tempt  is  made  to extract a FIFO when the FIFO already exists,
              this shall not be considered an error.

              The ownership, access, and modification times, and file mode  of
              the restored files are discussed under the -p option.

       write  In  write  mode (when -w is specified, but -r is not), pax shall
              write the contents of the file operands to the  standard  output
              in  an archive format. If no file operands are specified, a list
              of files to copy, one per line, shall be read from the  standard
              input.  A  file of type directory shall include all of the files
              in the file hierarchy rooted at the file.

       copy   In copy mode (when both -r and -w are specified), pax shall copy
              the file operands to the destination directory.

              If  no file operands are specified, a list of files to copy, one
              per line, shall be read from the standard input. A file of  type
              directory  shall  include all of the files in the file hierarchy
              rooted at the file.

              The effect of the copy shall be as  if  the  copied  files  were
              written  to an archive file and then subsequently extracted, ex-
              cept that there may be hard links between the original  and  the
              copied  files. If the destination directory is a subdirectory of
              one of the files to be copied, the results are  unspecified.  If
              the destination directory is a file of a type not defined by the
              System Interfaces volume of IEEE Std  1003.1-2001,  the  results
              are  implementation-defined; otherwise, it shall be an error for
              the file named by the directory operand not  to  exist,  not  be
              writable by the user, or not be a file of type directory.

       In read or copy modes, if intermediate directories are necessary to ex-
       tract an archive member, pax shall perform actions  equivalent  to  the
       mkdir()  function  defined  in the System Interfaces volume of IEEE Std
       1003.1-2001, called with the following arguments:

       o      The intermediate directory used as the path argument.

       o      The value of the bitwise-inclusive OR of S_IRWXU,  S_IRWXG,  and
              S_IRWXO as the mode argument.

       If  any  specified pattern or file operands are not matched by at least
       one file or archive member, pax shall write  a  diagnostic  message  to
       standard error for each one that did not match and exit with a non-zero
       exit status.

       The archive formats described in the EXTENDED DESCRIPTION section shall
       be  automatically  detected on input. The default output archive format
       shall be implementation-defined.

       The spax implementation defaults to -x ustar.

       A single archive can span multiple files. The pax utility shall  deter-
       mine,  in  an implementation-defined manner, what file to read or write
       as the next file.

       If the selected archive format supports  the  specification  of  linked
       files,  it  shall  be an error if these files cannot be linked when the
       archive is extracted, except that if the files to be  linked  are  sym-
       bolic  links and the system is not capable of making hard links to sym-
       bolic links, then separate copies of the symbolic link shall be created
       instead.  For archive formats that do not store file contents with each
       name that causes a hard link, if the file that contains the data is not
       extracted  during  this  pax session, either the data shall be restored
       from the original file, or a diagnostic message shall be displayed with
       the  name of a file that can be used to extract the data. In traversing
       directories, pax shall detect infinite loops; that is, entering a  pre-
       viously visited directory that is an ancestor of the last file visited.
       When it detects an infinite loop, pax shall write a diagnostic  message
       to standard error and shall terminate.

OPTIONS
       The  pax  utility  shall conform to the Base Definitions volume of IEEE
       Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines,  except  that
       the order of presentation of the -o, -p, and -s options is significant.
       See also the OTHER OPTIONS section.

       The following options shall be supported:

       -r     Read an archive file from standard input.

       -w     Write files to the standard output in the specified archive for-
              mat.

       -a     Append files to the end of the archive. It is implementation-de-
              fined which devices on the system support appending.  Additional
              file  formats unspecified by this volume of IEEE Std 1003.1-2001
              may impose restrictions on appending.

       -b blocksize
              Block the output at a positive decimal integer number  of  bytes
              per  write  to the archive file. Devices and archive formats may
              impose restrictions on blocking. Blocking shall be automatically
              determined on input. Conforming applications shall not specify a
              blocksize value larger than 32256.  Default blocking when creat-
              ing  archives  depends on the archive format. (See the -x option
              below.)

       -c     Match all file or archive members except those specified by  the
              pattern or file operands.

       -d     Cause  files  of  type directory being copied or archived or ar-
              chive members of type directory being  extracted  or  listed  to
              match  only  the  file or archive member itself and not the file
              hierarchy rooted at the file.

       -f archive
              Specify the pathname of the input or output archive,  overriding
              the  default  standard input (in list or read modes) or standard
              output (write mode).

       -H     If a symbolic link referencing a file of type directory is spec-
              ified  on the command line, pax shall archive the file hierarchy
              rooted in the file referenced by the link, using the name of the
              link  as  the  root of the file hierarchy.  Otherwise, if a sym-
              bolic link referencing a file of any other file type  which  pax
              can  normally archive is specified on the command line, then pax
              shall archive the file referenced by the link, using the name of
              the  link. The default behavior shall be to archive the symbolic
              link itself.

       -i     Interactively rename files or archive members. For each  archive
              member  matching a pattern operand or file matching a file oper-
              and, a prompt shall be written to the file /dev/tty.  The prompt
              shall  contain  the  name of the file or archive member, but the
              format is otherwise unspecified. A line shall then be read  from
              /dev/tty.  If  this  line  is  blank, the file or archive member
              shall be skipped. If this line consists of a single period,  the
              file  or  archive member shall be processed with no modification
              to its name. Otherwise, its name shall be replaced with the con-
              tents of the line. The pax utility shall immediately exit with a
              non-zero exit status if end-of-file is encountered when  reading
              a response or if /dev/tty cannot be opened for reading and writ-
              ing.

              The results of extracting a hard link to a file  that  has  been
              renamed during extraction are unspecified.

       -k     Prevent the overwriting of existing files.

       -l     (The letter ell.) In copy mode, hard links shall be made between
              the source and destination file hierarchies  whenever  possible.
              If  specified in conjunction with -H or -L, when a symbolic link
              is encountered, the hard link created in  the  destination  file
              hierarchy  shall be to the file referenced by the symbolic link.
              If specified when neither -H nor -L is specified,  when  a  sym-
              bolic  link  is  encountered,  the implementation shall create a
              hard link to the symbolic link in the source file  hierarchy  or
              copy the symbolic link to the destination.

       -L     If a symbolic link referencing a file of type directory is spec-
              ified on the command line or encountered during the traversal of
              a file hierarchy, pax shall archive the file hierarchy rooted in
              the file referenced by the link, using the name of the  link  as
              the  root  of the file hierarchy.  Otherwise, if a symbolic link
              referencing a file of any other file type which pax can normally
              archive  is  specified on the command line or encountered during
              the traversal of a file hierarchy, pax shall  archive  the  file
              referenced  by the link, using the name of the link. The default
              behavior shall be to archive the symbolic link itself.

       -n     Select the first archive member that matches each pattern  oper-
              and.  No  more than one archive member shall be matched for each
              pattern (although members of type directory  shall  still  match
              the file hierarchy rooted at that file).

       -o options
              Provide  information  to  the implementation to modify the algo-
              rithm for extracting or writing  files.  The  value  of  options
              shall  consist  of  one  or more comma-separated keywords of the
              form:

              keyword[[:]=value][,keyword[[:]=value],...]

              Some keywords apply only to certain file formats,  as  indicated
              with  each description. Use of keywords that are inapplicable to
              the file format being processed produces undefined results.

              Keywords in the options argument shall be a string that would be
              a  valid  portable filename as described in the Base Definitions
              volume of IEEE Std 1003.1-2001, Section 3.276, Portable Filename
              Character Set.

              Note:  Keywords are not expected to be filenames, merely to fol-
                     low the same  character  composition  rules  as  portable
                     filenames.

              Keywords can be preceded with white space. The value field shall
              consist of zero or more characters; within value,  the  applica-
              tion  shall  precede  any  literal comma with a backslash, which
              shall be ignored, but preserves the comma as part  of  value.  A
              comma  as  the  final  character,  or a comma followed solely by
              white space as the final characters, in  options  shall  be  ig-
              nored.  Multiple  -o options can be specified; if keywords given
              to these multiple -o options conflict, the keywords  and  values
              appearing  later  in command line sequence shall take precedence
              and the earlier shall be silently ignored. The following keyword
              values of options shall be supported for the file formats as in-
              dicated:

              delete=pattern
                     (Applicable only to the -x  pax  format.)  When  used  in
                     write  or  copy mode, pax shall omit from extended header
                     records that it produces any keywords matching the string
                     pattern. When used in read or list mode, pax shall ignore
                     any keywords matching the string pattern in the  extended
                     header  records.  In  both  cases, matching shall be per-
                     formed using the pattern matching notation  described  in
                     Patterns  Matching a Single Character and Patterns Match-
                     ing Multiple Characters. For example:

                     -o delete=security.*

                     would suppress security-related information. See pax  Ex-
                     tended Header for extended header record keyword usage.

                     When  multiple  -o  delete=pattern options are specified,
                     the patterns shall be additive; all keywords matching the
                     specified  string patterns shall be omitted from extended
                     header records that pax produces.

              exthdr.name=string
                     (Applicable only to the -x pax format.) This keyword  al-
                     lows  user control over the name that is written into the
                     ustar header blocks for the extended header produced  un-
                     der the circumstances described in pax Header Block.  The
                     name shall be the contents of string, after the following
                     character substitutions have been made:

                  +-----------------+---------------------------------------------+
                  |string Includes: | Replaced By:                                |
                  +-----------------+---------------------------------------------+
                  |%d               | The directory name of the file, equivalent  |
                  |                 | to the result of the dirname utility on the |
                  |                 | translated pathname.                        |
                  +-----------------+---------------------------------------------+
                  |%f               | The filename of the file, equivalent to the |
                  |                 | result of the basename utility on the       |
                  |                 | translated pathname.                        |
                  +-----------------+---------------------------------------------+
                  |%p               | The process ID of the pax process.          |
                  +-----------------+---------------------------------------------+
                  |%%               | A '%' character.                            |
                  +-----------------+---------------------------------------------+
                     Any  other '%' characters in string produce undefined re-
                     sults.

                     If no -o exthdr.name= string is specified, pax shall  use
                     the following default value:

                             %d/PaxHeaders.%p/%f

              globexthdr.name=string
                     (Applicable  only  to  the  -x  pax format.) When used in
                     write or copy mode  with  the  appropriate  options,  pax
                     shall  create  global  extended header records with ustar
                     header blocks that will be treated as  regular  files  by
                     previous  versions of pax.  This keyword allows user con-
                     trol over the name that is written into the ustar  header
                     blocks for global extended header records. The name shall
                     be the contents of string, after the following  character
                     substitutions have been made:

                  +-----------------+---------------------------------------------+
                  |string Includes: | Replaced By:                                |
                  +-----------------+---------------------------------------------+
                  |%n               | An integer that represents the sequence     |
                  |                 | number of the global extended header record |
                  |                 | in the archive, starting at 1.              |
                  +-----------------+---------------------------------------------+
                  |%p               | The process ID of the pax process.          |
                  +-----------------+---------------------------------------------+
                  |%%               | A '%' character.                            |
                  +-----------------+---------------------------------------------+
                     Any  other '%' characters in string produce undefined re-
                     sults.

                     If no -o globexthdr.name=string is specified,  pax  shall
                     use the following default value:

                     $TMPDIR/GlobalHead.%p.%n

                     where $TMPDIR represents the value of the TMPDIR environ-
                     ment variable. If TMPDIR is not set, pax shall use /tmp.

              invalid=action
                     (Applicable only to the -x pax format.) This keyword  al-
                     lows  user control over the action pax takes upon encoun-
                     tering values in an extended header record that, in  read
                     or  copy  mode,  are invalid in the destination hierarchy
                     or, in list mode, cannot be written in  the  codeset  and
                     current  locale  of the implementation. The following are
                     invalid values that shall be recognized by pax:

                     +      In read or copy mode, a filename or link name that
                            contains character encodings invalid in the desti-
                            nation hierarchy. (For example, the name may  con-
                            tain embedded NULs.)

                     +      In read or copy mode, a filename or link name that
                            is longer than the maximum allowed in the destina-
                            tion hierarchy (for either a pathname component or
                            the entire pathname).

                     +      In list mode, any character  string  value  (file-
                            name, link name, user name, and so on) that cannot
                            be written in the codeset and  current  locale  of
                            the implementation.

                     The following mutually-exclusive values of the action ar-
                     gument are supported:

                     bypass In read or copy mode, pax shall bypass  the  file,
                            causing no change to the destination hierarchy. In
                            list mode, pax shall  write  all  requested  valid
                            values  for  the  file, but its method for writing
                            invalid values is unspecified.

                     rename In read or copy mode, pax shall act as if  the  -i
                            option  were  in effect for each file with invalid
                            filename or link name values, allowing the user to
                            provide  a replacement name interactively. In list
                            mode, pax shall behave identically to  the  bypass
                            action.

                     UTF-8  When  used in read, copy, or list mode and a file-
                            name, link name, owner name, or any other field in
                            an  extended  header  record  cannot be translated
                            from the pax UTF-8 codeset format to  the  codeset
                            and  current  locale  of  the  implementation, pax
                            shall use the actual UTF-8 encoding for the name.

                     write  In read or copy mode, pax shall  write  the  file,
                            translating  the  name, regardless of whether this
                            may overwrite an existing file with a valid  name.
                            In  list mode, pax shall behave identically to the
                            bypass action.

                     If no -o invalid=option is specified, pax shall act as if
                     -o invalid= bypass were specified. Any overwriting of ex-
                     isting files that may be allowed by the -o  invalid=  ac-
                     tions shall be subject to permission(-p) and modification
                     time (-u) restrictions, and shall be suppressed if the -k
                     option is also specified.

              linkdata
                     (Applicable  only  to  the -x pax format.) In write mode,
                     pax shall write the contents of a  file  to  the  archive
                     even when that file is merely a hard link to a file whose
                     contents have already been written to the archive.

              listopt=format
                     This keyword specifies the output format of the table  of
                     contents produced when the -v option is specified in list
                     mode. See List Mode Format Specifications. To avoid ambi-
                     guity,  the  listopt=  format  shall be the only or final
                     keyword= value pair in a -o option-argument; all  charac-
                     ters  in  the  remainder  of the option-argument shall be
                     considered part of the format string.  When  multiple  -o
                     listopt= format options are specified, the format strings
                     shall be considered a single, concatenated string, evalu-
                     ated in command line order.

              times  (Applicable  only  to  the  -x  pax format.) When used in
                     write or copy mode, pax shall include atime and mtime ex-
                     tended  header  records  for  each file. See pax Extended
                     Header File Times.

              In addition to these keywords, if the -x pax  format  is  speci-
              fied,  any  of  the  keywords and values defined in pax Extended
              Header, including implementation extensions, can be used  in  -o
              option-arguments, in either of two modes:

              keyword=value
                     When  used  in  write  or  copy mode, these keyword/value
                     pairs shall be included at the beginning of  the  archive
                     as  typeflag  g global extended header records. When used
                     in read or list mode, these keyword/value pairs shall act
                     as  if  they  had been at the beginning of the archive as
                     typeflag g global extended header records.

              keyword:=value
                     When used in write  or  copy  mode,  these  keyword/value
                     pairs  shall be included as records at the beginning of a
                     typeflag x extended header for each file. (This shall  be
                     equivalent  to the equal-sign form except that it creates
                     no typeflag g global extended header records.) When  used
                     in read or list mode, these keyword/value pairs shall act
                     as if they were included as records at the  end  of  each
                     extended  header; thus, they shall override any global or
                     file-specific extended header record keywords of the same
                     names. For example, in the command:

                     pax -r -o "gname:=mygroup," <archive

                     the  group  name  will  be  forced to a new value for all
                     files read from the archive.

              The precedence of -o keywords over various fields in the archive
              is described in pax Extended Header Keyword Precedence.

       -p string
              Specify  one  or  more file characteristic options (privileges).
              The string option-argument shall be  a  string  specifying  file
              characteristics  to be retained or discarded on extraction.  The
              string shall consist of the specification characters a ,  e,  m,
              o,  and  p.  Other  implementation-defined characters can be in-
              cluded. Multiple characteristics can be concatenated within  the
              same  string and multiple -p options can be specified. The mean-
              ing of the specification characters are as follows:

              a      Do not preserve file access times.

              e      Preserve the user ID, group ID, file mode bits  (see  the
                     Base  Definitions volume of IEEE Std 1003.1-2001, Section
                     3.168, File Mode Bits), access time,  modification  time,
                     and  any  other  implementation-defined file characteris-
                     tics.

              m

                     Do not preserve file modification times.

              o      Preserve the user ID and group ID.

              p      Preserve the file mode bits. Other implementation-defined
                     file mode attributes may be preserved.

              In  the  preceding  list, "preserve" indicates that an attribute
              stored in the archive shall be given to the extracted file, sub-
              ject  to the permissions of the invoking process. The access and
              modification times of the file shall be preserved unless  other-
              wise  specified with the -p option or not stored in the archive.
              All attributes that are not preserved  shall  be  determined  as
              part  of  the normal file creation action (see File Read, Write,
              and Creation).

              If neither the e nor the o specification character is specified,
              or  the  user  ID and group ID are not preserved for any reason,
              pax shall not set the S_ISUID and S_ISGID bits of the file mode.

              If the preservation of any of these items fails for any  reason,
              pax  shall write a diagnostic message to standard error. Failure
              to preserve these items shall affect the final exit status,  but
              shall not cause the extracted file to be deleted.

              If file characteristic letters in any of the string option-argu-
              ments are duplicated or conflict with each other, the ones given
              last shall take precedence. For example, if -p eme is specified,
              file modification times are preserved.

       -s replstr
              Modify file or archive member names named by pattern or file op-
              erands  according  to the substitution expression replstr, using
              the syntax of the ed utility.  The  concepts  of  "address"  and
              "line"  are  meaningless  in the context of the pax utility, and
              shall not be supplied. The format shall be:

              -s /old/new/[gp]

              where as in ed, old is a basic regular expression  and  new  can
              contain  an ampersand, '\n' (where n is a digit) backreferences,
              or subexpression matching. The old string shall also be  permit-
              ted to contain <newline>s.

              Any  non-null  character  can be used as a delimiter ( '/' shown
              here). Multiple -s expressions can be specified; the expressions
              shall  be  applied  in the order specified, terminating with the
              first successful substitution. The optional trailing 'g'  is  as
              defined in the ed utility. The optional trailing 'p' shall cause
              successful substitutions to be written to standard  error.  File
              or  archive  member  names  that  substitute to the empty string
              shall be ignored when reading and writing archives.

       -t     When reading files from the file system, and if the user has the
              permissions required by utime() to do so, set the access time of
              each file read to the access time that it had before being  read
              by pax.

       -u     Ignore files that are older (having a less recent file modifica-
              tion time) than a pre-existing file or archive member  with  the
              same name. In read mode, an archive member with the same name as
              a file in the file system shall be extracted if the archive mem-
              ber  is newer than the file. In write mode, an archive file mem-
              ber with the same name as a file in the file system shall be su-
              perseded  if the file is newer than the archive member. If -a is
              also specified, this is accomplished by  appending  to  the  ar-
              chive; otherwise, it is unspecified whether this is accomplished
              by actual replacement in the archive or by appending to the  ar-
              chive. In copy mode, the file in the destination hierarchy shall
              be replaced by the file in the source hierarchy or by a link  to
              the file in the source hierarchy if the file in the source hier-
              archy is newer.

       -v     In list mode, produce a verbose table of contents (see the  STD-
              OUT section). Otherwise, write archive member pathnames to stan-
              dard error (see the STDERR section).

       -x format
              Specify the output archive format. The pax utility shall support
              the following formats:

              cpio   The cpio interchange format; see the EXTENDED DESCRIPTION
                     section. The default blocksize for this format for  char-
                     acter  special  archive  files shall be 5120. Implementa-
                     tions shall support all blocksize  values  less  than  or
                     equal to 32256 that are multiples of 512.

              pax    The  pax interchange format; see the EXTENDED DESCRIPTION
                     section. The default blocksize for this format for  char-
                     acter  special  archive files shall be 5120.  Implementa-
                     tions shall support all blocksize  values  less  than  or
                     equal to 32256 that are multiples of 512.

              ustar  The  tar interchange format; see the EXTENDED DESCRIPTION
                     section. The default blocksize for this format for  char-
                     acter  special archive files shall be 10240.  Implementa-
                     tions shall support all blocksize  values  less  than  or
                     equal to 32256 that are multiples of 512.

              Implementation-defined  formats  shall  specify  a default block
              size as well as any other block sizes  supported  for  character
              special archive files.

              Any  attempt  to append to an archive file in a format different
              from the existing archive format shall cause pax to exit immedi-
              ately with a non-zero exit status.

              In  copy mode, if no -x format is specified, pax shall behave as
              if -x pax were specified.

       -X     When traversing the file hierarchy specified by a pathname,  pax
              shall  not descend into directories that have a different device
              ID ( st_dev; see  the  System  Interfaces  volume  of  IEEE  Std
              1003.1-2001, stat()).

       Specifying  more  than  one of the mutually-exclusive options -H and -L
       shall not be considered an error and the last  option  specified  shall
       determine the behavior of the utility.

       The  options that operate on the names of files or archive members (-c,
       -i, -n, -s, -u, and -v) shall interact as follows. In  read  mode,  the
       archive  members  shall be selected based on the user-specified pattern
       operands as modified by the -c, -n, and -u options. Then, any -s and -i
       options  shall  modify, in that order, the names of the selected files.
       The -v option shall write names resulting from these modifications.

       In write mode, the files shall be selected based on the  user-specified
       pathnames  as  modified  by the -n and -u options.  Then, any -s and -i
       options shall modify, in that order, the names of these selected files.
       The -v option shall write names resulting from these modifications.

       If  both  the -u and -n options are specified, pax shall not consider a
       file selected unless it is newer than the file to which it is compared.

   List Mode Format Specifications
       The manual page for spax is not yet ready.  The  following  text  is  a
       quotation from the POSIX.1-2001 standard.

       In  list  mode  with  the -o listopt=format option, the format argument
       shall be applied for each selected file. The pax utility shall append a
       <newline>  to the listopt output for each selected file. The format ar-
       gument shall be used as the format string described in the Base Defini-
       tions  volume of IEEE Std 1003.1-2001, Chapter 5, File Format Notation,
       with the exceptions 1. through 5.  defined in the EXTENDED  DESCRIPTION
       section of printf(3), plus the following exceptions:

       6.     The  sequence  (keyword)  can  occur  before a format conversion
              specifier. The conversion argument is defined by  the  value  of
              keyword.   The  implementation  shall support the following key-
              words:

              o      Any of the Field Name entries in ustar Header  Block  and
                     Octet-Oriented cpio Archive Entry. The implementation may
                     support the cpio keywords without the leading c_ in addi-
                     tion  to  the  form  required  by  Values for cpio c_mode
                     Field.

              o      Any keyword defined for the extended header  in  pax  Ex-
                     tended Header.

              o      Any  keyword provided as an implementation-defined exten-
                     sion within the extended header defined in  pax  Extended
                     Header.

              For  example,  the sequence "%(charset)s" is the string value of
              the name of the character set in the extended header.

              The result of the keyword conversion argument shall be the value
              from the applicable header field or extended header, without any
              trailing NULs.

              All keyword values used as conversion arguments shall be  trans-
              lated  from  the UTF-8 encoding to the character set appropriate
              for the local file system, user database, and so on, as applica-
              ble.

       7.     An  additional  conversion specifier character, T, shall be used
              to specify time formats. The T  conversion  specifier  character
              can  be preceded by the sequence (keyword=subformat), where sub-
              format is a date format as defined by date operands. The default
              keyword shall be mtime and the default subformat shall be:

                 %b %e %H:%M %Y

       8.     An  additional  conversion specifier character, M, shall be used
              to specify the file mode string as  defined  in  ls(1)  Standard
              Output. If (keyword) is omitted, the mode keyword shall be used.
              For example, %.1M writes the single character  corresponding  to
              the <entry type> field of the ls -l command.

       9.     An  additional  conversion specifier character, D, shall be used
              to specify the device for block or special files, if applicable,
              in  an  implementation-defined  format.  If  not applicable, and
              (keyword) is specified, then this conversion shall be equivalent
              to  %(keyword)u.   If  not applicable, and (keyword) is omitted,
              then this conversion shall be equivalent to <space>.

       10.    An additional conversion specifier character, F, shall  be  used
              to  specify  a  pathname. The F conversion character can be pre-
              ceded by a sequence of comma-separated keywords:

                 (keyword[,keyword] ... )
              The values for all the keywords that are non-null shall be  con-
              catenated  together,  each separated by a '/'. The default shall
              be (path) if the keyword path is defined; otherwise, the default
              shall be (prefix, name).

       11.    An  additional  conversion specifier character, L, shall be used
              to specify a symbolic line expansion. If the current file  is  a
              symbolic link, then %L shall expand to:

                 "%s -> %s", <value of keyword>, <contents of link>

       Otherwise,  the  %L conversion specification shall be the equivalent of
       %F.

OPERANDS
       The following operands shall be supported:

       directory
              The destination directory pathname for copy mode.

       file   A pathname of a file to be copied or archived.

       pattern
              A pattern matching one or more pathnames of archive members.   A
              pattern  must  be  given  in the name-generating notation of the
              pattern matching notation in Pattern Matching Notation , includ-
              ing  the  filename expansion rules in Patterns Used for Filename
              Expansion. The default, if no pattern is specified, is to select
              all members in the archive.

STDIN
       In  write  mode, the standard input shall be used only if no file oper-
       ands are specified. It shall be a text file containing a list of  path-
       names, one per line, without leading or trailing <blank>s.

       In  list  and  read  modes,  if -f is not specified, the standard input
       shall be an archive file.

       Otherwise, the standard input shall not be used.

INPUT FILES
       The input file named by the archive option-argument, or standard  input
       when  the archive is read from there, shall be a file formatted accord-
       ing to one of the specifications in the EXTENDED DESCRIPTION section or
       some other implementation-defined format.

       The file /dev/tty shall be used to write prompts and read responses.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of pax:

       LANG   Provide  a  default value for the internationalization variables
              that are unset or null. (See the Base Definitions volume of IEEE
              Std 1003.1-2001, Section 8.2, Internationalization Variables for
              the precedence of internationalization variables used to  deter-
              mine the values of locale categories.)

       LC_ALL If  set  to a non-empty string value, override the values of all
              the other internationalization variables.

       LC_COLLATE
              Determine the locale for the  behavior  of  ranges,  equivalence
              classes, and multi-character collating elements used in the pat-
              tern matching expressions for the  pattern  operand,  the  basic
              regular  expression  for the -s option, and the extended regular
              expression defined for the yesexpr locale keyword in the LC_MES-
              SAGES category.

       LC_CTYPE
              Determine  the  locale  for  the  interpretation of sequences of
              bytes of text data as characters (for  example,  single-byte  as
              opposed  to multi-byte characters in arguments and input files),
              the behavior of character classes used in the  extended  regular
              expression defined for the yesexpr locale keyword in the LC_MES-
              SAGES category, and pattern matching.

       LC_MESSAGES
              Determine the locale for the processing of affirmative responses
              that  should  be used to affect the format and contents of diag-
              nostic messages written to standard error.

       LC_TIME
              Determine the format and contents of date and time strings  when
              the -v option is specified.

       NLSPATH
              [XSI]  [Option Start] Determine the location of message catalogs
              for the processing of LC_MESSAGES . [Option End]

       TMPDIR Determine the pathname that provides part of the default  global
              extended header record file, as described for the -o globexthdr=
              keyword in the OPTIONS section.

       TZ     Determine the timezone used to calculate date and  time  strings
              when  the -v option is specified. If TZ is unset or null, an un-
              specified default timezone shall be used.

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       In write mode, if -f is not specified, the standard output shall be the
       archive  formatted  according  to  one of the specifications in the EX-
       TENDED DESCRIPTION section, or some other implementation-defined format
       (see -x format).

       In  list  mode, when the -o listopt= format has been specified, the se-
       lected archive members shall be written to standard  output  using  the
       format  described  under  List Mode Format Specifications. In list mode
       without the -o listopt= format option, the table of contents of the se-
       lected  archive  members  shall be written to standard output using the
       following format:

            "%s\n", <pathname>

       If the -v option is specified in list mode, the table  of  contents  of
       the  selected archive members shall be written to standard output using
       the following formats.

       For pathnames representing hard links to previous members  of  the  ar-
       chive:

            "%s == %s\n", <ls -l listing>, <linkname>

       For all other pathnames:

            "%s\n", <ls -l listing>

       where  <ls -l listing> shall be the format specified by the ls(1) util-
       ity with the -l option. When writing pathnames in this  format,  it  is
       unspecified what is written for fields for which the underlying archive
       format does not have the correct information, although the correct num-
       ber of <blank>-separated fields shall be written.

       In list mode, standard output shall not be buffered more than a line at
       a time.

STDERR
       If -v is specified in read, write, or copy modes, pax shall  write  the
       pathnames it processes to the standard error output using the following
       format:

            "%s\n", <pathname>

       These pathnames shall be written as soon as processing is begun on  the
       file  or  archive  member,  and shall be flushed to standard error. The
       trailing <newline>, which shall not be buffered, is  written  when  the
       file has been read or written.

       If  the -s option is specified, and the replacement string has a trail-
       ing 'p', substitutions shall be written to standard error in  the  fol-
       lowing format:

            "%s >> %s\n", <original pathname>, <new pathname>

       In  all operating modes of pax, optional messages of unspecified format
       concerning the input archive format and volume number,  the  number  of
       files,  blocks,  volumes,  and  media parts as well as other diagnostic
       messages may be written to standard error.

       In all formats, for both standard output and standard error, it is  un-
       specified  how  non-printable characters in pathnames or link names are
       written.

       When pax is in read mode or list mode, using the -x pax archive format,
       and  a  filename,  link  name, owner name, or any other field in an ex-
       tended header record cannot be translated from the  pax  UTF-8  codeset
       format  to  the  codeset  and current locale of the implementation, pax
       shall write a diagnostic message to standard error, shall  process  the
       file  as  described  for the -o invalid= option, and then shall process
       the next file in the archive.

OUTPUT FILES
       In read mode, the extracted output files shall be of the archived  file
       type.  In  copy  mode, the copied output files shall be the type of the
       file being copied. In either mode, existing files  in  the  destination
       hierarchy shall be overwritten only when all permission (-p), modifica-
       tion time (-u), and invalid-value (-o invalid=) tests allow it.

       In write mode, the output file named by the -f option-argument shall be
       a file formatted according to one of the specifications in the EXTENDED
       DESCRIPTION section, or some other implementation-defined format.

EXTENDED DESCRIPTION
   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 identi-
       cal to the ustar format described in  ustar  Interchange  Format.  Each
       file archived shall be represented by the following sequence:

              o      An  optional  header  block with extended header records.
                     This header block 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.

              o      A header block that describes the file. Any fields in the
                     preceding optional extended header shall override the as-
                     sociated fields in this header block for this file.

              o      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.

       A  schematic  of an example archive with global extended header records
       and two actual files is shown in pax Format Archive Example. In the ex-
       ample,  the second file in the archive has no extended header preceding
       it, presumably because it has no need for extended attributes.

                         Figure: pax Format Archive Example

    +------------------------------+---------------------------------------------+
    |ustar Header [typeflag = 'g'] |                                             |
    +------------------------------+           Global Extended header            |
    |Global Extended Header Data   |                                             |
    +------------------------------+---------------------------------------------+
    |ustar Header [typeflag = 'x'] |                                             |
    +------------------------------+                                             |
    |Extended Header Data          |                                             |
    +------------------------------+  File 1: Extended Header data is included   |
    |ustar Header [typeflag = '0'] |                                             |
    +------------------------------+                                             |
    |Data for File 1               |                                             |
    +------------------------------+---------------------------------------------+
    |ustar Header [typeflag = '0'] |                                             |
    +------------------------------+ File 2: No Extended Header data is included |
    |Data for File 2               |                                             |
    +------------------------------+---------------------------------------------+
    |Block of binary Zeroes        |                                             |
    +------------------------------+          End of Archive Indicator           |
    |Block of binary Zeroes        |                                             |
    +------------------------------+---------------------------------------------+

   pax Header Block
       The pax header block shall be identical to the ustar header  block  de-
       scribed  in  ustar Interchange Format, except that two additional type-
       flag values are defined:

       x      Represents extended header records for the following file in the
              archive (which shall have its own ustar header block).  The for-
              mat of these extended header records shall be  as  described  in
              pax Extended Header.

       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 interchange 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 ex-
       tended header records in octets. The other fields in the  header  block
       are  not  meaningful  to  this version of the pax utility.  However, if
       this  archive  is  read  by  a  pax  utility  conforming  to  the   ISO
       POSIX-2:1993  standard,  the  header  block fields are used to create a
       regular file that contains the extended header records as data.  There-
       fore,  header  block field values should be selected to provide reason-
       able file access to this regular file.

       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 cre-
       ated  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 re-
       quiring a character encoding other than that described in  the  ISO/IEC
       646:1991 standard, fields representing file attributes not described in
       the ustar header, and fields whose format or length do not fit the  re-
       quirements  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 keywords.

       An extended header shall consist of one or more records, each construc-
       ted as follows:

            "%d %s=%s\n", <length>, <keyword>, <value>

       The  extended  header records shall be encoded according to the ISO/IEC
       10646-1:2000 standard (UTF-8).  The  <length>  field,  <blank>,  equals
       sign,  and  <newline>  shown shall be limited to the portable character
       set, as encoded in UTF-8. The <keyword> and <value> fields can  be  any
       UTF-8 characters. The <length> field shall be the decimal length of the
       extended header record in octets, including the trailing <newline>.

       The <keyword> field shall be one of the entries from the following list
       or  a  keyword  provided as an implementation extension.  Keywords con-
       sisting entirely of lowercase letters, digits, and periods are reserved
       for future standardization. A keyword shall not include an equals sign.
       (In the following list, the notations "file(s)" or "block(s)"  is  used
       to acknowledge that a keyword affects the following single file after a
       typeflag x extended header, but possibly multiple files after  typeflag
       g.   Any  requirements  in the list for pax to include a record when in
       write or copy mode shall apply only when such a record has not  already
       been provided through the use of the -o option. When used in copy mode,
       pax shall behave as if an archive had been created with applicable  ex-
       tended header records and then extracted.)

       atime  The  file  access  time for the following file(s), equivalent to
              the value of the st_atime member of the  stat  structure  for  a
              file,  as  described  by  the  stat(2) function. The access time
              shall be restored if the process has the  appropriate  privilege
              required  to  do  so.  The format of the <value> shall be as de-
              scribed in pax Extended Header File Times.

       charset
              The name of the character set used to encode  the  data  in  the
              following  file(s).  The  entries in the following table are de-
              fined to refer to  known  standards;  additional  names  may  be
              agreed on between the originator and recipient.

              +------------------------+-------------------------------+
              |        <value>         |        Formal Standard        |
              +------------------------+-------------------------------+
              |ISO-IR 646 1990         | ISO/IEC 646:1990              |
              |ISO-IR 8859 1 1998      | ISO/IEC 8859-1:1998           |
              |ISO-IR 8859 2 1999      | ISO/IEC 8859-2:1999           |
              |ISO-IR 8859 3 1999      | ISO/IEC 8859-3:1999           |
              |ISO-IR 8859 4 1998      | ISO/IEC 8859-4:1998           |
              |ISO-IR 8859 5 1999      | ISO/IEC 8859-5:1999           |
              |ISO-IR 8859 6 1999      | ISO/IEC 8859-6:1999           |
              |ISO-IR 8859 7 1987      | ISO/IEC 8859-7:1987           |
              |ISO-IR 8859 8 1999      | ISO/IEC 8859-8:1999           |
              |ISO-IR 8859 9 1999      | ISO/IEC 8859-9:1999           |
              |ISO-IR 8859 10 1998     | ISO/IEC 8859-10:1998          |
              |ISO-IR 8859 13 1998     | ISO/IEC 8859-13:1998          |
              |ISO-IR 8859 14 1998     | ISO/IEC 8859-14:1998          |
              |ISO-IR 8859 15 1999     | ISO/IEC 8859-15:1999          |
              |ISO-IR 10646 2000       | ISO/IEC 10646:2000            |
              |ISO-IR 10646 2000 UTF-8 | ISO/IEC 10646, UTF-8 encoding |
              |BINARY                  | None                          |
              +------------------------+-------------------------------+
       The  encoding  is  included in an extended header for information only;
       when pax is used as described in IEEE Std  1003.1-2001,  it  shall  not
       translate the file data into any other encoding. The BINARY entry indi-
       cates unencoded binary data.

       When used in write or copy mode, it is  implementation-defined  whether
       pax includes a charset extended header record for a file.

       comment
              A  series of characters used as a comment. All characters in the
              <value> field shall be ignored by pax.

       gid    The group ID of the group that owns the  file,  expressed  as  a
              decimal  number using digits from the ISO/IEC 646:1991 standard.
              This record shall override the gid field in the following header
              block(s).  When  used in write or copy mode, pax shall include a
              gid extended header record for  each  file  whose  group  ID  is
              greater than 2097151 (octal 7777777).

       gname  The group of the file(s), formatted as a group name in the group
              database. This record shall override the gid and gname fields in
              the  following  header  block(s),  and  any  gid extended header
              record. When used in read, copy, or list mode, pax shall  trans-
              late  the  name  from the UTF-8 encoding in the header record to
              the character set appropriate for the group database on the  re-
              ceiving  system. If any of the UTF-8 characters cannot be trans-
              lated, and if the -o invalid=UTF-8 option is not specified,  the
              results  are  implementation-defined. When used in write or copy
              mode, pax shall include a gname extended header record for  each
              file  whose  group  name cannot be represented entirely with the
              letters and digits of the portable character set.

       linkpath
              The pathname of a link being created to  another  file,  of  any
              type,  previously  archived.  This  record  shall  override  the
              linkname field in the following ustar header block(s). The  fol-
              lowing  ustar header block shall determine the type of link cre-
              ated. If typeflag of the following header block is 1,  it  shall
              be  a  hard  link. If typeflag is 2, it shall be a symbolic link
              and the linkpath value shall be the  contents  of  the  symbolic
              link. The pax utility shall translate the name of the link (con-
              tents of the symbolic link) from the UTF-8 encoding to the char-
              acter  set  appropriate  for the local file system. When used in
              write or copy mode, pax shall include a linkpath extended header
              record  for  each  link whose pathname cannot be represented en-
              tirely with the members of the portable character set other than
              NUL.

       mtime  The  file modification time of the following file(s), equivalent
              to the value of the st_mtime member of the stat structure for  a
              file,  as  described in the stat(2) function.  This record shall
              override the mtime field in the following header  block(s).  The
              modification  time  shall be restored if the process has the ap-
              propriate privilege required  to  do  so.   The  format  of  the
              <value> shall be as described in pax Extended Header File Times.

       path   The  pathname  of the following file(s). This record shall over-
              ride  the  name  and  prefix  fields  in  the  following  header
              block(s).  The  pax  utility shall translate the pathname of the
              file from the UTF-8 encoding to the  character  set  appropriate
              for the local file system.

              When  used  in  write or copy mode, pax shall include a path ex-
              tended header record for each file whose pathname cannot be rep-
              resented entirely with the members of the portable character set
              other than NUL.

       realtime.any
              The keywords prefixed by "realtime."  are  reserved  for  future
              standardization.

       security.any
              The  keywords  prefixed  by  "security." are reserved for future
              standardization.

       size   The size of the file in octets, expressed as  a  decimal  number
              using  digits  from  the  ISO/IEC 646:1991 standard. This record
              shall override the size field in the following header  block(s).
              When  used  in  write or copy mode, pax shall include a size ex-
              tended header record for each file with  a  size  value  greater
              than 8589934591 (octal 77777777777).

       uid    The user ID of the file owner, expressed as a decimal number us-
              ing digits from the ISO/IEC 646:1991 standard. This record shall
              override  the  uid  field in the following header block(s). When
              used in write or copy mode, pax shall  include  a  uid  extended
              header  record  for  each  file  whose  owner ID is greater than
              2097151 (octal 7777777).

       uname  The owner of the following file(s), formatted as a user name  in
              the  user database. This record shall override the uid and uname
              fields in the following header block(s), and  any  uid  extended
              header  record. When used in read, copy, or list mode, pax shall
              translate the name from the UTF-8 encoding in the header  record
              to  the  character  set appropriate for the user database on the
              receiving system. If any  of  the  UTF-8  characters  cannot  be
              translated, and if the -o invalid=UTF-8 option is not specified,
              the results are implementation-defined. When used  in  write  or
              copy  mode, pax shall include a uname extended header record for
              each file whose user name cannot be  represented  entirely  with
              the letters and digits of the portable character set.

       If  the  <value> field is zero length, it shall delete any header block
       field, previously entered extended header  value,  or  global  extended
       header value of the same name.

       If  a keyword in an extended header record (or in a -o option-argument)
       overrides or deletes a corresponding field in the ustar  header  block,
       pax shall ignore the contents of that header block field.

       Unlike  the ustar header block fields, NULs shall not delimit <value>s;
       all characters within the <value> field shall be  considered  data  for
       the  field.  None  of  the length limitations of the ustar header block
       fields in ustar  Header  Block  shall  apply  to  the  extended  header
       records.

   pax Extended Header Keyword Precedence
       This  section  describes  the  precedence  in  which the various header
       records and fields and command line options are selected to apply to  a
       file  in  the archive. When pax is used in read or list modes, it shall
       determine a file attribute in the following sequence:

              1.     If -o delete=keyword-prefix is  used,  the  affected  at-
                     tributes shall be determined from step 7., if applicable,
                     or ignored otherwise.

              2.     If -o keyword:= is used, the affected attributes shall be
                     ignored.

              3.     If  -o  keyword:=value  is  used,  the affected attribute
                     shall be assigned the value.

              4.     If there is a typeflag x extended header record, the  af-
                     fected attribute shall be assigned the <value>.  When ex-
                     tended header records conflict, the last one given in the
                     header shall take precedence.

              5.     If -o keyword=value is used, the affected attribute shall
                     be assigned the value.

              6.     If there is a typeflag g global extended  header  record,
                     the  affected  attribute  shall  be assigned the <value>.
                     When global extended header records  conflict,  the  last
                     one given in the global header shall take precedence.

              7.     Otherwise, the attribute shall be determined from the us-
                     tar header block.

   pax Extended Header File Times
       The pax utility shall write an mtime record for each file in  write  or
       copy  modes  if  the file's modification time cannot be represented ex-
       actly in the ustar header logical record described in ustar Interchange
       Format.   This  can  occur if the time is out of ustar range, or if the
       file system of the underlying implementation supports non-integer  time
       granularities and the time is not an integer. All of these time records
       shall be formatted as a decimal representation of the time  in  seconds
       since  the Epoch. If a period ('.') decimal point character is present,
       the digits to the right of the point shall represent  the  units  of  a
       subsecond timing granularity, where the first digit is tenths of a sec-
       ond and each subsequent digit is a tenth of the previous digit. In read
       or  copy mode, the pax utility shall truncate the time of a file to the
       greatest value that is not greater than the input header file time.  In
       write  or  copy mode, the pax utility shall output a time exactly if it
       can be represented exactly as a decimal  number,  and  otherwise  shall
       generate only enough digits so that the same time shall be recovered if
       the file is extracted on a system whose underlying implementation  sup-
       ports the same time granularity.

   ustar Interchange Format
       A ustar archive tape or file shall contain a series of logical records.
       Each logical record shall be a fixed-size logical record of 512  octets
       (see  below). Although this format may be thought of as being stored on
       9-track industry-standard 12.7 mm (0.5 in) magnetic tape,  other  types
       of  transportable  media  are not excluded. Each file archived shall be
       represented by a header logical record that describes  the  file,  fol-
       lowed  by  zero  or  more logical records that give the contents of the
       file. At the end of the archive file there shall be two 512-octet logi-
       cal  records filled with binary zeros, interpreted as an end-of-archive
       indicator.

       The logical records may be grouped for physical I/O operations, as  de-
       scribed under the -b blocksize and -x ustar options. Each group of log-
       ical records may be written with a single operation equivalent  to  the
       write(2)  function. On magnetic tape, the result of this write shall be
       a single tape physical block. The last physical block shall  always  be
       the  full  size,  so logical records after the two zero logical records
       may contain undefined data.

       The header logical record shall be structured as shown in the following
       table. All lengths and offsets are in decimal.

                              Table: ustar Header Block

                  +-----------+--------------+--------------------+
                  |Field Name | Octet Offset | Length (in Octets) |
                  +-----------+--------------+--------------------+
                  |name       |       0      |        100         |
                  |mode       |     100      |          8         |
                  |uid        |     108      |          8         |
                  |gid        |     116      |          8         |
                  |size       |     124      |         12         |
                  |mtime      |     136      |         12         |
                  |chksum     |     148      |          8         |
                  |typeflag   |     156      |          1         |
                  |linkname   |     157      |        100         |
                  |magic      |     257      |          6         |
                  |version    |     263      |          2         |
                  |uname      |     265      |         32         |
                  |gname      |     297      |         32         |
                  |devmajor   |     329      |          8         |
                  |devminor   |     337      |          8         |
                  |prefix     |     345      |        155         |
                  +-----------+--------------+--------------------+
       All characters in the header logical record shall be represented in the
       coded character set of  the  ISO/IEC  646:1991  standard.  For  maximum
       portability  between  implementations,  names  should  be selected from
       characters represented by the portable filename character set as octets
       with  the  most significant bit zero. If an implementation supports the
       use of characters outside of slash and the portable filename  character
       set  in names for files, users, and groups, one or more implementation-
       defined encodings of these characters shall be provided for interchange
       purposes.

       However, the pax utility shall never create filenames on the local sys-
       tem that cannot be accessed via the procedures described  in  IEEE  Std
       1003.1-2001.  If a filename is found on the medium that would create an
       invalid filename, it is implementation-defined whether  the  data  from
       the  file  is  stored  on  the file hierarchy and under what name it is
       stored. The pax utility may choose to ignore these files as long as  it
       produces an error indicating that the file is being ignored.

       Each  field  within  the  header logical record is contiguous; that is,
       there is no padding used. Each character on the archive medium shall be
       stored contiguously.

       The  fields  magic,  uname, and gname are character strings each termi-
       nated by a NUL character. The fields name,  linkname,  and  prefix  are
       NUL-terminated  character strings except when all characters in the ar-
       ray contain non-NUL characters including the last character.  The  ver-
       sion  field  is  two octets containing the characters "00" (zero-zero).
       The typeflag contains a single character. All other fields are  leading
       zero-filled  octal numbers using digits from the ISO/IEC 646:1991 stan-
       dard IRV. Each numeric field is terminated by one or  more  <space>  or
       NUL characters.

       The  name and the prefix fields shall produce the pathname of the file.
       A new pathname shall be formed, if prefix is not an empty  string  (its
       first  character  is not NUL), by concatenating prefix (up to the first
       NUL character), a slash character, and name; otherwise,  name  is  used
       alone.  In  either case, name is terminated at the first NUL character.
       If prefix begins with a NUL character, it shall  be  ignored.  In  this
       manner,  pathnames  of  at  most  256 characters can be supported. If a
       pathname does not fit in the space provided, pax shall notify the  user
       of  the error, and shall not store any part of the file-header or data-
       on the medium.

       The linkname field, described below, shall not use the prefix  to  pro-
       duce  a  pathname. As such, a linkname 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.

       The  mode  field provides 12 bits encoded in the ISO/IEC 646:1991 stan-
       dard octal digit representation. The encoded bits shall  represent  the
       following values:

                               Table: ustar mode Field

     +------+-----------------+-------------------------------------------------+
     | Bit  |    IEEE Std     |                   Description                   |
     |Value | 1003.1-2001 Bit |                                                 |
     +------+-----------------+-------------------------------------------------+
     |04000 | S_ISUID         | Set UID on execution.                           |
     |02000 | S_ISGID         | Set GID on execution.                           |
     |01000 | <reserved>      | Reserved for future standardization.            |
     |00400 | S_IRUSR         | Read permission for file owner class.           |
     |00200 | S_IWUSR         | Write permission for file owner class.          |
     |00100 | S_IXUSR         | Execute/search permission for file owner class. |
     |00040 | S_IRGRP         | Read permission for file group class.           |
     |00020 | S_IWGRP         | Write permission for file group class.          |
     |00010 | S_IXGRP         | Execute/search permission for file group class. |
     |00004 | S_IROTH         | Read permission for file other class.           |
     |00002 | S_IWOTH         | Write permission for file other class.          |
     |00001 | S_IXOTH         | Execute/search permission for file other class. |
     +------+-----------------+-------------------------------------------------+
       When  appropriate  privilege is required to set one of these mode bits,
       and the user restoring the files from the archive does not have the ap-
       propriate privilege, the mode bits for which the user does not have ap-
       propriate privilege shall be ignored. Some of the mode bits in the  ar-
       chive  format  are  not  mentioned elsewhere in this volume of IEEE Std
       1003.1-2001. If the implementation does not support  those  bits,  they
       may be ignored.

       The uid and gid fields are the user and group ID of the owner and group
       of the file, respectively.

       The size field is the size of the file in octets. If the typeflag field
       is  set  to  specify  a  file to be of type 1 (a link) or 2 (a symbolic
       link), the size field shall be specified as zero. If the typeflag field
       is set to specify a file of type 5 (directory), the size field shall be
       interpreted as described under the definition of that record  type.  No
       data  logical  records are stored for types 1, 2, or 5. If the typeflag
       field is set to 3 (character special file), 4 (block special file),  or
       6  (FIFO),  the meaning of the size field is unspecified by this volume
       of IEEE Std 1003.1-2001, and no data logical records shall be stored on
       the  medium.  Additionally, for type 6, the size field shall be ignored
       when reading. If the typeflag field is set to any other value, the num-
       ber   of   logical  records  written  following  the  header  shall  be
       (size+511)/512, ignoring any fraction in the result of the division.

       The mtime field shall be the modification time of the file at the  time
       it  was archived. It is the ISO/IEC 646:1991 standard representation of
       the octal value of the modification  time  obtained  from  the  stat(2)
       function.

       The chksum field shall be the ISO/IEC 646:1991 standard IRV representa-
       tion of the octal value of the simple sum of all octets in  the  header
       logical  record.  Each  octet  in the header shall be treated as an un-
       signed value. These values shall be added to an unsigned integer,  ini-
       tialized to zero, the precision of which is not less than 17 bits. When
       calculating the checksum, the chksum field is treated as if it were all
       spaces.

       The typeflag field specifies the type of file archived. If a particular
       implementation does not recognize the type, or the user does  not  have
       appropriate  privilege to create that type, the file shall be extracted
       as if it were a regular file if the file type  is  defined  to  have  a
       meaning  for the size field that could cause data logical records to be
       written on the medium (see the previous description for size).  If con-
       version  to a regular file occurs, the pax utility shall produce an er-
       ror indicating that the conversion took  place.  All  of  the  typeflag
       fields shall be coded in the ISO/IEC 646:1991 standard IRV:

       0      Represents  a regular file. For backwards-compatibility, a type-
              flag value of binary zero ('\0') should be recognized as meaning
              a  regular file when extracting files from the archive. Archives
              written with this version of the archive file format create reg-
              ular files with a typefla value of the ISO/IEC 646:1991 standard
              IRV '0'.

       1      Represents a file linked to another file, of  any  type,  previ-
              ously archived. Such files are identified by having the same de-
              vice and file serial numbers, and pathnames that refer  to  dif-
              ferent  directory  entries.  All such files shall be archived as
              linked files. The linked-to name is specified  in  the  linkname
              field  with  a  NUL-character  terminator if it is less than 100
              octets in length.

       2      Represents a symbolic link. The contents of  the  symbolic  link
              shall be stored in the linkname field.

       3,4    Represent  character  special  files and block special files re-
              spectively. In this case the devmajor and devminor fields  shall
              contain  information defining the device, the format of which is
              unspecified by this volume of IEEE Std 1003.1-2001.  Implementa-
              tions may map the device specifications to their own local spec-
              ification or may ignore the entry.

       5      Specifies a directory or subdirectory. On systems where disk al-
              location is performed on a directory basis, the size field shall
              contain the maximum number of octets (which may  be  rounded  to
              the  nearest  disk block allocation unit) that the directory may
              hold. A size field of zero indicates no such  limiting.  Systems
              that  do  not  support limiting in this manner should ignore the
              size field.

       6      Specifies a FIFO special file. Note that the archiving of a FIFO
              file archives the existence of this file and not its contents.

       7      Reserved  to represent a file to which an implementation has as-
              sociated some high-performance attribute. Implementations  with-
              out  such  extensions  should  treat this file as a regular file
              (type 0).

       A-Z    The letters 'A' to 'Z', inclusive, are reserved for  custom  im-
              plementations. All other values are reserved for future versions
              of IEEE Std 1003.1-2001.

       It is unspecified whether files with pathnames that refer to  the  same
       directory  entry  are archived as linked files or as separate files. If
       they are archived as linked files, this means that  attempting  to  ex-
       tract  both  pathnames  from the resulting archive will always cause an
       error (unless the -u option is used) because the link  cannot  be  cre-
       ated.

       It  is  unspecified  whether files with the same device and file serial
       numbers being appended to an archive are treated  as  linked  files  to
       members that were in the archive before the append.

       Attempts  to archive a socket using ustar interchange format shall pro-
       duce a diagnostic message. Handling of other file types is  implementa-
       tion-defined.

       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 NUL), the un-
       ame and gname fields shall contain the ISO/IEC  646:1991  standard  IRV
       representation  of the owner and group of the file, respectively (trun-
       cated to fit, if necessary).  When the file is  restored  by  a  privi-
       leged, 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.

   cpio Interchange Format
       The octet-oriented cpio archive format shall be a  series  of  entries,
       each comprising a header that describes the file, the name of the file,
       and then the contents of the file.

       An archive may be recorded as a series of fixed-size blocks of  octets.
       This  blocking  shall be used only to make physical I/O more efficient.
       The last group of blocks shall always be at the full size.

       For the octet-oriented cpio archive format, the individual entry infor-
       mation  shall  be in the order indicated and described by the following
       table; see also the <cpio.h> header.

                      Table: Octet-Oriented cpio Archive Entry

            +---------------------+--------------------+-----------------+
            | Header Field Name   | Length (in Octets) | Interpreted as  |
            +---------------------+--------------------+-----------------+
            |c_magic              | 6                  | Octal number    |
            |c_dev                | 6                  | Octal number    |
            |c_ino                | 6                  | Octal number    |
            |c_mode               | 6                  | Octal number    |
            |c_uid                | 6                  | Octal number    |
            |c_gid                | 6                  | Octal number    |
            |c_nlink              | 6                  | Octal number    |
            |c_rdev               | 6                  | Octal number    |
            |c_mtime              | 11                 | Octal number    |
            |c_namesize           | 6                  | Octal number    |
            |c_filesize           | 11                 | Octal number    |
            |                     |                    |                 |
            |Filename Field Name  | Length             | Interpreted as  |
            |c_name               | c_namesize         | Pathname string |
            |                     |                    |                 |
            |File Data Field Name | Length             | Interpreted as  |
            |c_filedata           | c_filesize         | Data            |
            +---------------------+--------------------+-----------------+
   cpio Header
       For each file in the archive, a header as defined previously  shall  be
       written.  The information in the header fields is written as streams of
       the ISO/IEC 646:1991 standard characters interpreted as octal  numbers.
       The  octal numbers shall be extended to the necessary length by append-
       ing the ISO/IEC 646:1991 standard IRV zeros  at  the  most-significant-
       digit  end of the number; the result is written to the most-significant
       digit of the stream of octets first. The fields shall be interpreted as
       follows:

       c_magic
              Identify  the  archive  as being a transportable archive by con-
              taining the identifying value "070707".

       c_dev, c_ino
              Contains values that uniquely identify the file within  the  ar-
              chive  (that  is,  no  files  contain the same pair of c_dev and
              c_ino values unless they are links to the same file). The values
              shall be determined in an unspecified manner.

       c_mode Contains  the file type and access permissions as defined in the
              following table.

                            Table: Values for cpio c_mode Field

                 +----------------------+---------+------------------------+
                 |File Permissions Name |  Value  |       Indicates        |
                 +----------------------+---------+------------------------+
                 |C_IRUSR               | 000400  | Read by owner          |
                 |C_IWUSR               | 000200  | Write by owner         |
                 |C_IXUSR               | 000100  | Execute by owner       |
                 |C_IRGRP               | 000040  | Read by group          |
                 |C_IWGRP               | 000020  | Write by group         |
                 |C_IXGRP               | 000010  | Execute by group       |
                 |C_IROTH               | 000004  | Read by others         |
                 |C_IWOTH               | 000002  | Write by others        |
                 |C_IXOTH               | 000001  | Execute by others      |
                 |C_ISUID               | 004000  | Set uid                |
                 |C_ISGID               | 002000  | Set gid                |
                 |C_ISVTX               | 001000  | Reserved               |
                 +----------------------+---------+------------------------+
                 |File Type Name        | Value   | Indicates              |
                 +----------------------+---------+------------------------+
                 |C_ISDIR               | 0040000 | Directory              |
                 |C_ISFIFO              | 0010000 | FIFO                   |
                 |C_ISREG               | 0100000 | Regular file           |
                 |C_ISLNK               | 0120000 | Symbolic link          |
                 |C_ISBLK               | 0060000 | Block special file     |
                 |C_ISCHR               | 0020000 | Character special file |
                 |C_ISSOCK              | 0140000 | Socket                 |
                 |C_ISCTG               | 0110000 | Reserved               |
                 +----------------------+---------+------------------------+
              Directories, FIFOs, symbolic links, and regular files  shall  be
              supported  on  a  system  conforming  to this volume of IEEE Std
              1003.1-2001; additional values defined previously  are  reserved
              for  compatibility with existing systems.  Additional file types
              may be supported; however, such files should not be  written  to
              archives intended to be transported to other systems.

       c_uid  Contains the user ID of the owner.

       c_gid  Contains the group ID of the group.

       c_nlink
              Contains  a  number greater than or equal to the number of links
              in the archive referencing the file. If the -a option is used to
              append  to a cpio archive, then the pax utility need not account
              for the files in the existing part of the archive when calculat-
              ing the c_nlink values for the appended part of the archive, and
              need not alter the c_nlink values in the existing  part  of  the
              archive if additional files with the same c_dev and c_ino values
              are appended to the archive.

       c_rdev Contains implementation-defined  information  for  character  or
              block special files.

       c_mtime
              Contains the latest time of modification of the file at the time
              the archive was created.

       c_namesize
              Contains the length of the pathname, including  the  terminating
              NUL character.

       c_filesize
              Contains  the  length  of  the file in octets. This shall be the
              length of the data section following the header structure.

   cpio Filename
       The c_name field shall contain the pathname of the file. The length  of
       this field in octets is the value of c_namesize.

       If a filename is found on the medium that would create an invalid path-
       name, it is implementation-defined whether the data from  the  file  is
       stored on the file hierarchy and under what name it is stored.

       All  characters  shall  be represented in the ISO/IEC 646:1991 standard
       IRV. For maximum portability between implementations, names  should  be
       selected from characters represented by the portable filename character
       set as octets with the most significant bit zero. If an  implementation
       supports  the use of characters outside the portable filename character
       set in names for files, users, and groups, one or more  implementation-
       defined encodings of these characters shall be provided for interchange
       purposes. However, the pax utility shall never create filenames on  the
       local  system that cannot be accessed via the procedures described pre-
       viously in this volume of IEEE Std 1003.1-2001. If a filename is  found
       on  the medium that would create an invalid filename, it is implementa-
       tion-defined whether the data from the file is stored on the local file
       system  and under what name it is stored. The pax utility may choose to
       ignore these files as long as it produces an error indicating that  the
       file is being ignored.

   cpio File Data
       Following  c_name, there shall be c_filesize octets of data.  Interpre-
       tation of such data occurs in  a  manner  dependent  on  the  file.  If
       c_filesize is zero, no data shall be contained in c_filedata.

       When restoring from an archive:

       o      If  the user does not have the appropriate privilege to create a
              file of the specified type, pax shall ignore the entry and write
              an error message to standard error.

       o      Only regular files have data to be restored. Presuming a regular
              file meets any selection criteria that might be imposed  on  the
              format-reading utility by the user, such data shall be restored.

       o      If  a user does not have appropriate privilege to set a particu-
              lar mode flag, the flag shall be ignored. Some of the mode flags
              in the archive format are not mentioned elsewhere in this volume
              of IEEE Std 1003.1-2001. If the implementation does not  support
              those flags, they may be ignored.

   cpio Special Entries
       FIFO special files, directories, and the trailer shall be recorded with
       c_filesize equal to zero. For other special files,  c_filesize  is  un-
       specified  by  this  volume of IEEE Std 1003.1-2001. The header for the
       next file entry in the archive shall be written directly after the last
       octet  of  the  file entry preceding it. A header denoting the filename
       TRAILER!!!  shall indicate the end of  the  archive;  the  contents  of
       octets in the last block of the archive following such a header are un-
       defined.

EXIT STATUS
       The following exit values shall be returned:

        0     All files were processed successfully.

       >0     An error occurred.

CONSEQUENCES OF ERRORS
       If pax cannot create a file or a link when reading an archive or cannot
       find  a  file  when writing an archive, or cannot preserve the user ID,
       group ID, or file mode when the -p option is  specified,  a  diagnostic
       message  shall  be written to standard error and a non-zero exit status
       shall be returned, but processing shall continue. In the case where pax
       cannot  create  a  link  to a file, pax shall not, by default, create a
       second copy of the file.

       If the extraction of a file from an archive is  prematurely  terminated
       by a signal or error, pax may have only partially extracted the file or
       (if the -n option was not specified) may have extracted a file  of  the
       same  name as that specified by the user, but which is not the file the
       user wanted. Additionally, the file modes of extracted directories  may
       have  additional  bits  from  the S_IRWXU mask set as well as incorrect
       modification and access times.

_________________________________________________________________
The following sections are informative.

APPLICATION USAGE
       Caution is advised when using the -a option to append to a cpio  format
       archive. If any of the files being appended happen to be given the same
       c_dev and c_ino values as a file in the existing part of  the  archive,
       then  they may be treated as links to that file on extraction. Thus, it
       is risky to use -a with cpio format except when it is done on the  same
       system  that the original archive was created on, and with the same pax
       utility, and in the knowledge that there has been  little  or  no  file
       system  activity since the original archive was created that could lead
       to any of the files appended being given the same c_dev and c_ino  val-
       ues  as  an  unrelated  file in the existing part of the archive. Also,
       when (intentionally) appending additional links to a file in the exist-
       ing part of the archive, the c_nlink values in the modified archive can
       be smaller than the number of links to the file in the  archive,  which
       may mean that the links are not preserved on extraction.

       The  -p  (privileges)  option was invented to reconcile differences be-
       tween historical tar and cpio implementations. In particular,  the  two
       utilities use -m in diametrically opposed ways. The -p option also pro-
       vides a consistent means of extending the ways in which future file at-
       tributes  can  be  addressed,  such as for enhanced security systems or
       high-performance files. Although it may seem complex, there are  really
       two modes that are most commonly used:

       -p e   ``Preserve everything". This would be used by the historical su-
              peruser, someone with all the appropriate  privileges,  to  pre-
              serve  all  aspects of the files as they are recorded in the ar-
              chive. The e flag is the sum of o and p, and  other  implementa-
              tion-defined attributes.

       -p p   ``Preserve"  the  file mode bits. This would be used by the user
              with regular privileges who wished to preserve  aspects  of  the
              file  other  than the ownership. The file times are preserved by
              default, but two other flags are offered to  disable  these  and
              use the time of extraction.

       The  one pathname per line format of standard input precludes pathnames
       containing <newline>s. Although such  pathnames  violate  the  portable
       filename  guidelines, they may exist and their presence may inhibit us-
       age of pax within shell scripts. This problem is inherited from histor-
       ical  archive  programs. The problem can be avoided by listing filename
       arguments on the command line instead of on standard input.

       It is almost certain that appropriate privileges are required  for  pax
       to  accomplish  parts of this volume of IEEE Std 1003.1-2001.  Specifi-
       cally, creating files of  type  block  special  or  character  special,
       restoring file access times unless the files are owned by the user (the
       -t option), or preserving file owner, group, and mode (the  -p  option)
       all probably require appropriate privileges.

       In read mode, implementations are permitted to overwrite files when the
       archive has multiple members with the same name. This may fail if  per-
       missions  on the first version of the file do not permit it to be over-
       written.

       The cpio and ustar formats can only  support  files  up  to  8589934592
       bytes (8 * 2^30) in size.

EXAMPLES
       The following command:

            pax -w -f /dev/rmt/1m .

       copies  the  contents  of the current directory to tape drive 1, medium
       density (assuming historical System V device naming procedures-the his-
       torical BSD device name would be /dev/rmt9).

       The following commands:

            mkdir newdirpax -rw olddir newdir

       copy the olddir directory hierarchy to newdir.

            pax -r -s ',^//*usr//*,,' -f a.pax

       reads  the  archive a.pax, with all files rooted in /usr in the archive
       extracted relative to the current directory.

       Using the option:

            -o listopt="%M %(atime)T %(size)D %(name)s"

       overrides the default output description in Standard Output and instead
       writes:

            -rw-rw--- Jan 12 15:53 1492 /usr/foo/bar

       Using the options:

            -o listopt='%L\t%(size)D\n%.7' \
            -o listopt='(name)s\n%(atime)T\n%T'

       overrides the default output description in Standard Output and instead
       writes:

       /usr/foo/bar -> /tmp   1492
       /usr/fo
       Jan 12 1991
       Jan 31 15:53

RATIONALE
       The pax utility was new for the ISO POSIX-2:1993  standard.  It  repre-
       sents a peaceful compromise between advocates of the historical tar and
       cpio utilities.

       A fundamental difference between cpio and tar was in the  way  directo-
       ries  were  treated. The cpio utility did not treat directories differ-
       ently from other files, and to select a directory and its contents  re-
       quired  that  each  file  in the hierarchy be explicitly specified. For
       tar, a directory matched every file in the file hierarchy it rooted.

       The pax utility offers both interfaces;  by  default,  directories  map
       into the file hierarchy they root. The -d option causes pax to skip any
       file not explicitly referenced, as cpio historically did.   The  tar  -
       style  behavior  was chosen as the default because it was believed that
       this was the more common usage and because tar  is  the  more  commonly
       available  interface,  as it was historically provided on both System V
       and BSD implementations.

       The data interchange format specification in this volume  of  IEEE  Std
       1003.1-2001 requires that processes with "appropriate privileges" shall
       always restore the ownership and permissions of extracted files exactly
       as  archived. If viewed from the historic equivalence between superuser
       and "appropriate privileges", there are two problems with this require-
       ment.  First, users running as superusers may unknowingly set dangerous
       permissions on extracted files. Second, it is needlessly  limiting,  in
       that  superusers  cannot extract files and own them as superuser unless
       the archive was created by the superuser.  (It  should  be  noted  that
       restoration  of  ownerships  and  permissions for the superuser, by de-
       fault, is historical practice in cpio, but not in tar.)   In  order  to
       avoid  these  two  problems,  the  pax  specification has an additional
       "privilege" mechanism, the -p option. Only a pax  invocation  with  the
       privileges needed, and which has the -p option set using the e specifi-
       cation character, has the "appropriate privilege" to restore full  own-
       ership and permission information.

       Note  also  that  this volume of IEEE Std 1003.1-2001 requires that the
       file ownership and access permissions shall be set, on  extraction,  in
       the  same  fashion as the creat(2) function when provided with the mode
       stored in the archive. This means that the file creation  mask  of  the
       user is applied to the file permissions.

       Users should note that directories may be created by pax while extract-
       ing files with permissions that are different from those  that  existed
       at the time the archive was created. When extracting sensitive informa-
       tion into a directory hierarchy that no longer exists,  users  are  en-
       couraged to set their file creation mask appropriately to protect these
       files during extraction.

       The table of contents output is written to standard output  to  facili-
       tate pipeline processing.

       An  early  proposal  had hard links displaying for all pathnames.  This
       was removed because it complicates the output of the case where  -v  is
       not  specified  and does not match historical cpio usage. The hard-link
       information is available in the -v display.

       The description of the -l option allows implementations  to  make  hard
       links  to symbolic links. IEEE Std 1003.1-2001 does not specify any way
       to create a hard link to a symbolic link, but many implementations pro-
       vide  this  capability as an extension. If there are hard links to sym-
       bolic links when an archive is created, the implementation is  required
       to archive the hard link in the archive (unless -H or -L is specified).
       When in read mode and in copy  mode,  implementations  supporting  hard
       links to symbolic links should use them when appropriate.

       The  archive formats inherited from the POSIX.1-1990 standard have cer-
       tain restrictions that have been brought along from  historical  usage.
       For  example,  there are restrictions on the length of pathnames stored
       in the archive. When pax is used in copy (-rw) mode (copying  directory
       hierarchies),  the  ability  to  use  extensions from the -x pax format
       overcomes these restrictions.

       The default blocksize value of 5120 bytes for cpio was selected because
       it  is  one of the standard block-size values for cpio, set when the -B
       option is specified. (The other default block-size value  for  cpio  is
       512  bytes, and this was considered to be too small.) The default block
       value of 10240 bytes for tar was selected because that is the  standard
       block-size  value  for  BSD tar.  The maximum block size of 32256 bytes
       (2^15-512 bytes) is the largest multiple of 512 bytes that fits into  a
       signed  16-bit tape controller transfer register. There are known limi-
       tations in some historical systems that  would  prevent  larger  blocks
       from  being accepted. Historical values were chosen to improve compati-
       bility with historical scripts using dd(1) or similar utilities to  ma-
       nipulate  archives.  Also,  default block sizes for any file type other
       than character special file has been deleted from this volume  of  IEEE
       Std  1003.1-2001  as unimportant and not likely to affect the structure
       of the resulting archive.

       Implementations are permitted to modify the block-size value  based  on
       the archive format or the device to which the archive is being written.
       This is to provide implementations with the opportunity to take  advan-
       tage  of  special types of devices, and it should not be used without a
       great deal of consideration as it almost  certainly  decreases  archive
       portability.

       The  intended  use  of the -n option was to permit extraction of one or
       more files from the archive without processing the entire archive. This
       was  viewed  by the standard developers as offering significant perfor-
       mance advantages over historical  implementations.  The  -n  option  in
       early proposals had three effects; the first was to cause special char-
       acters in patterns to not be treated specially. The second was to cause
       only  the  first file that matched a pattern to be extracted. The third
       was to cause pax to write a diagnostic message to standard  error  when
       no  file was found matching a specified pattern. Only the second behav-
       ior is retained by this volume of IEEE Std 1003.1-2001, for  many  rea-
       sons.  First,  it  is  in general not acceptable for a single option to
       have multiple effects. Second, the ability  to  make  pattern  matching
       characters  act  as  normal characters is useful for parts of pax other
       than file extraction. Third, a finer degree of control over the special
       characters  is useful because users may wish to normalize only a single
       special character in a single filename. Fourth, given  a  more  general
       escape  mechanism, the previous behavior of the -n option can be easily
       obtained using the -s option or a sed script. Finally, writing a  diag-
       nostic message when a pattern specified by the user is unmatched by any
       file is useful behavior in all cases.

       In this version, the -n was removed from the copy mode synopsis of pax;
       it  is  inapplicable because there are no pattern operands specified in
       this mode.

       There is another method than pax  for  copying  subtrees  in  IEEE  Std
       1003.1-2001  described  as  part of the cp(1) utility. Both methods are
       historical practice: cp(1) provides a simpler,  more  intuitive  inter-
       face,  while  pax  offers a finer granularity of control. Each provides
       additional functionality to the other; in particular, pax maintains the
       hard-link  structure  of  the hierarchy while cp(1) does not. It is the
       intention of the standard developers that the results be similar (using
       appropriate option combinations in both utilities). The results are not
       required to be identical; there seemed insufficient  gain  to  applica-
       tions  to balance the difficulty of implementations having to guarantee
       that the results would be exactly identical.

       A single archive may span more than one file. It is suggested that  im-
       plementations  provide informative messages to the user on standard er-
       ror whenever the archive file is changed.

       The -d option (do not create intermediate directories not listed in the
       archive)  found in early proposals was originally provided as a comple-
       ment to the historic -d option of cpio.  It has been deleted.

       The -s option in early proposals specified a subset of the substitution
       command  from  the ed utility. As there was no reason for only a subset
       to be supported, the -s option is now compatible with  the  current  ed
       specification.  Since  the delimiter can be any non-null character, the
       following usage with single spaces is valid:

            pax -s " foo bar " ...

       The -t description is worded so as to note that this may cause the  ac-
       cess  time update caused by some other activity (which occurs while the
       file is being read) to be overwritten.

       The default behavior of pax with regard to file modification  times  is
       the  same as historical implementations of tar.  It is not the histori-
       cal behavior of cpio.

       Because the -i option uses /dev/tty, utilities  without  a  controlling
       terminal are not able to use this option.

       The  -y  option,  found  in early proposals, has been deleted because a
       line containing a single period for the -i option has equivalent  func-
       tionality. The special lines for the -i option (a single period and the
       empty line) are historical practice in cpio.

       In early drafts, a -e charmap option was included to increase portabil-
       ity of files between systems using different coded character sets. This
       option was omitted because it was apparent that consensus could not  be
       formed  for it. In this version, the use of UTF-8 should be an adequate
       substitute.

       The -k option was added to address  international  concerns  about  the
       dangers  involved  in  the  character set transformations of -e (if the
       target character set were different  from  the  source,  the  filenames
       might  be  transformed into names matching existing files) and also was
       made more general to protect files  transferred  between  file  systems
       with  different  {NAME_MAX}  values (truncating a filename on a smaller
       system might also inadvertently overwrite existing files).  As  stated,
       it  prevents any overwriting, even if the target file is older than the
       source. This version adds more granularity of  options  to  solve  this
       problem  by  introducing the -o invalid=option - specifically the UTF-8
       action. (Note that an existing file that is named with a UTF-8 encoding
       is still subject to overwriting in this case. The -k option closes that
       loophole.)

       Some of the file characteristics referenced in this volume of IEEE  Std
       1003.1-2001  might  not be supported by some archive formats. For exam-
       ple, neither the tar nor cpio formats contain the file access time. For
       this  reason, the e specification character has been provided, intended
       to cause all file characteristics specified in the archive  to  be  re-
       tained.

       It  is  required that extracted directories, by default, have their ac-
       cess and modification times and permissions set to the values specified
       in  the  archive. This has obvious problems in that the directories are
       almost certainly modified after being extracted and that directory per-
       missions may not permit file creation. One possible solution is to cre-
       ate directories with the mode specified in the archive, as modified  by
       the  umask  of the user, with sufficient permissions to allow file cre-
       ation. After all files have been extracted, pax would  then  reset  the
       access and modification times and permissions as necessary.

       The  list-mode  formatting description borrows heavily from the one de-
       fined by the printf(1) utility. However, since there is no separate op-
       erand  list to get conversion arguments, the format was extended to al-
       low specifying the name of the conversion argument as part of the  con-
       version specification.

       The T conversion specifier allows time fields to be displayed in any of
       the date formats. Unlike the ls(1) utility, pax  does  not  adjust  the
       format  when  the  date is less than six months in the past. This makes
       parsing the output more predictable.

       The D conversion specifier handles the ability to display the major/mi-
       nor or file size, as with ls(1), by using %-8(size)D.

       The L conversion specifier handles the ls display for symbolic links.

       Conversion  specifiers were added to generate existing known types used
       for ls(1).

   pax Interchange Format
       The new POSIX data interchange format was developed primarily  to  sat-
       isfy  international  concerns  that  the ustar and cpio formats did not
       provide for file, user, and group names encoded in characters outside a
       subset  of the ISO/IEC 646:1991 standard. The standard developers real-
       ized that this new POSIX data interchange format should be very  exten-
       sible  because  there  were other requirements they foresaw in the near
       future:

       o      Support international character encodings and locale information

       o      Support security information (ACLs, and so on)

       o      Support future file types, such as realtime or contiguous files

       o      Include data areas for implementation use

       o      Support systems with words larger than 32 bits and  timers  with
              subsecond granularity

       The  following  were not goals for this format because these are better
       handled by separate utilities or are inappropriate for a portable  for-
       mat:

       o      Encryption

       o      Compression

       o      Data translation between locales and codesets

       o      inode storage

       The  format  chosen  to  support the goals is an extension of the ustar
       format. Of the two formats previously available, only the ustar  format
       was selected for extensions because:

       o      It was easier to extend in an upwards-compatible way. It offered
              version flags and header block type fields with room for  future
              standardization. The cpio format, while possessing a more flexi-
              ble file naming  methodology,  could  not  be  extended  without
              breaking  some theoretical implementation or using a dummy file-
              name that could be a legitimate filename.

       o      Industry experience since the original "tar wars" fought in  de-
              veloping  the  ISO POSIX-1 standard has clearly been in favor of
              the ustar format, which is generally the default  output  format
              selected for pax implementations on new systems.

       The  new  format was designed with one additional goal in mind: reason-
       able behavior when an older tar or pax utility happened to read an  ar-
       chive.  Since the POSIX.1-1990 standard mandated that a "format-reading
       utility" had to treat unrecognized typeflag values  as  regular  files,
       this  allowed  the  format to include all the extended information in a
       pseudo-regular file that preceded each real file. An  option  is  given
       that  allows  the  archive creator to set up reasonable names for these
       files on the older systems.  Also, the  normative  text  suggests  that
       reasonable file access values be used for this ustar header block. Mak-
       ing these header files inaccessible for convenient reading and deleting
       would not be reasonable. File permissions of 600 or 700 are suggested.

       The  ustar  typeflag field was used to accommodate the additional func-
       tionality of the new format rather than magic or  version  because  the
       POSIX.1-1990 standard (and, by reference, the previous version of pax),
       mandated the behavior of the format-reading utility when it encountered
       an unknown typeflag, but was silent about the other two fields.

       Early proposals of the first revision to IEEE Std 1003.1-2001 contained
       a proposed archive format that was  based  on  compatibility  with  the
       standard  for tape files (ISO 1001, similar to the format used histori-
       cally on many mainframes and minicomputers).  This  format  was  overly
       complex  and  required  considerable  overhead  in  volume  and  header
       records. Furthermore, the standard developers felt that it would not be
       acceptable  to  the  community  of  POSIX  developers,  so it was later
       changed to be a format more closely related to historical  practice  on
       POSIX systems.

       The  prefix  and  name  split of pathnames in ustar was replaced by the
       single path extended header record for simplicity.

       The concept of a global extended header (typeflag g) was controversial.
       If  this  were applied to an archive being recorded on magnetic tape, a
       few unreadable blocks at the beginning of the tape could be  a  serious
       problem; a utility attempting to extract as many files as possible from
       a damaged archive could lose a large percentage of file header informa-
       tion  in  this case. However, if the archive were on a reliable medium,
       such as a CD-ROM, the global extended header offers considerable poten-
       tial  size  reductions  by eliminating redundant information. Thus, the
       text warns against using the global method  for  unreliable  media  and
       provides  a  method  for  implanting global information in the extended
       header for each file, rather than in the typeflag g records.

       No facility for data translation or filtering on a  per-file  basis  is
       included  because the standard developers could not invent an interface
       that would allow this in an efficient manner. If a filter, such as  en-
       cryption  or compression, is to be applied to all the files, it is more
       efficient to apply the filter to the entire archive as a  single  file.
       The standard developers considered interfaces that would invoke a shell
       script for each file going into or out of the archive, but  the  system
       overhead in this approach was considered to be too high.

       One such approach would be to have filter= records that give a pathname
       for an executable. When the program is invoked, the  file  and  archive
       would be open for standard input/output and all the header fields would
       be available as environment variables or  command-line  arguments.  The
       standard  developers  did  discuss  such schemes, but they were omitted
       from IEEE Std 1003.1-2001 due to  concerns  about  excessive  overhead.
       Also,  the program itself would need to be in the archive if it were to
       be used portably.

       There is currently no  portable  means  of  identifying  the  character
       set(s)  used for a file in the file system. Therefore, pax has not been
       given a mechanism to generate charset records automatically.  The  only
       portable means of doing this is for the user to write the archive using
       the -o charset=string command line option. This assumes that all of the
       files  in  the  archive  use the same encoding. The "implementation-de-
       fined" text is included to allow for a system that can identify the en-
       codings used for each of its files.

       The  table of standards that accompanies the charset record description
       is acknowledged to be very limited. Only a limited number of  character
       set  standards is reasonable for maximal interchange. Any character set
       is, of course, possible by  prior  agreement.  It  was  suggested  that
       EBCDIC  be  listed,  but  it was omitted because it is not defined by a
       formal standard. Formal standards, and then only those with  reasonably
       large  followings,  can be included here, simply as a matter of practi-
       cality. The <value>s represent names of officially registered character
       sets in the format required by the ISO 2375:1985 standard.

       The  normal  comma  or <blank>-separated list rules are not followed in
       the case of keyword options to  allow  ease  of  argument  parsing  for
       getopts.

       Further  information on character encodings is in pax Archive Character
       Set Encoding/Decoding.

       The standard developers have reserved keyword name space for vendor ex-
       tensions. It is suggested that the format to be used is:

           VENDOR.keyword

       where VENDOR is the name of the vendor or organization in all uppercase
       letters. It is further suggested that the keyword following the  period
       be named differently than any of the standard keywords so that it could
       be used for future standardization, if  appropriate,  by  omitting  the
       VENDOR prefix.

       The  <length>  field in the extended header record was included to make
       it simpler to step through the records, even if a  record  contains  an
       unknown  format (to a particular pax) with complex interactions of spe-
       cial characters. It also provides a minor integrity  checkpoint  within
       the records to aid a program attempting to recover files from a damaged
       archive.

       There are no extended header versions  of  the  devmajor  and  devminor
       fields because the unspecified format ustar header field should be suf-
       ficient. If they are not, vendor-specific extended  keywords  (such  as
       VENDOR.devmajor) should be used.

       Device  and i-number labeling of files was not adopted from cpio; files
       are interchanged strictly on a symbolic name basis, as in ustar.

       Just as with the ustar format descriptions, the  new  format  makes  no
       special arrangements for multi-volume archives. Each of the pax archive
       types is assumed to be inside a single POSIX file  and  splitting  that
       file  over  multiple  volumes  (diskettes, tape cartridges, and so on),
       processing their labels, and mounting each in the proper  sequence  are
       considered  to  be  implementation  details  that  cannot  be described
       portably.

       The pax format is intended for interchange, not only for  backup  on  a
       single  (family  of)  systems.  It is not as densely packed as might be
       possible for backup:

       o      It contains information as coded characters that could be  coded
              in binary.

       o      It  identifies  extended  records with name fields that could be
              omitted in favor of a fixed-field layout.

       o      It translates names into a portable character set and identifies
              locale-related  information, both of which are probably unneces-
              sary for backup.

       The requirements on restoring from an archive  are  slightly  different
       from  the  historical wording, allowing for non-monolithic privilege to
       bring forward as much as possible. In particular,  attributes  such  as
       "high  performance  file"  might be broadly but not universally granted
       while set-user-ID or chown(2) might be much more restricted.  There  is
       no implication in IEEE Std 1003.1-2001 that the security information be
       honored after it is restored to the file hierarchy, in  spite  of  what
       might  be  improperly  inferred by the silence on that topic. That is a
       topic for another standard.

       Links are recorded in the fashion described here because a link can  be
       to any file type. It is desirable in general to be able to restore part
       of an archive selectively and restore all of those files completely. If
       the  data  is  not  associated with each link, it is not possible to do
       this. However, the data associated with a file can be large,  and  when
       selective  restoration is not needed, this can be a significant burden.
       The archive is structured so that files that have  no  associated  data
       can  always  be  restored by the name of any link name of any link, and
       the user may choose whether data is recorded with each  instance  of  a
       file  that  contains  data.  The format permits mixing of both types of
       links in a single archive; this can be done for special needs, and  pax
       is  expected  to interpret such archives on input properly, despite the
       fact that there is no pax option that would force this  mixed  case  on
       output.  (When  -o linkdata is used, the output must contain the dupli-
       cate data, but the implementation is free to include it or omit it when
       -o linkdata is not used.)

       The  time  values are included as extended header records for those im-
       plementations needing more than the eleven octal digits allowed by  the
       ustar  format. Portable file timestamps cannot be negative.  If pax en-
       counters a file with a negative timestamp in copy or write mode, it can
       reject  the  file,  substitute  a non-negative timestamp, or generate a
       non-portable timestamp with a leading '-'. Even though some implementa-
       tions  can support finer file-time granularities than seconds, the nor-
       mative text requires support only for seconds since the  Epoch  because
       the  ISO  POSIX-1  standard  states them that way. The ustar format in-
       cludes only mtime; the new format adds atime and  ctime  for  symmetry.
       The  atime  access time restored to the file system will be affected by
       the -p a and -p e options. The ctime creation time (actually inode mod-
       ification  time)  is  described with "appropriate privilege" so that it
       can be ignored when writing to the file system. POSIX does not  provide
       a  portable  means to change file creation time. Nothing is intended to
       prevent a non-portable implementation of pax from restoring the value.

       The gid, size, and uid extended header records were included  to  allow
       expansion  beyond  the  sizes  specified in the regular tar header. New
       file system architectures are emerging that will exhaust  the  12-digit
       size  field.  There are probably not many systems requiring more than 8
       digits for user and group IDs, but the extended header values were  in-
       cluded for completeness, allowing overrides for all of the decimal val-
       ues in the tar header.

       The standard developers intended to describe the effective  results  of
       pax with regard to file ownerships and permissions; implementations are
       not restricted in timing or sequencing the restoration  of  such,  pro-
       vided the results are as specified.

       Much  of  the  text  describing  the  extended headers refers to use in
       "write or copy modes". The copy mode references are due to  the  norma-
       tive text: "The effect of the copy shall be as if the copied files were
       written to an archive file and then subsequently extracted ...".  There
       is  certainly no way to test whether pax is actually generating the ex-
       tended headers in copy mode, but the effects must be as if it had.

   pax Archive Character Set Encoding/Decoding
       There is a need to exchange archives of files between systems  of  dif-
       ferent  native codesets. Filenames, group names, and user names must be
       preserved to the fullest extent possible when an archive is read on the
       receiving  platform. Translation of the contents of files is not within
       the scope of the pax utility.

       There will also be the need to represent characters that are not avail-
       able  on the receiving platform. These unsupported characters cannot be
       automatically folded to the local set of characters due to  the  chance
       of  collisions.  This  could  result  in overwriting previous extracted
       files from the archive or pre-existing files on the system.

       For these reasons, the codeset used to represent characters within  the
       extended header records of the pax archive must be sufficiently rich to
       handle all commonly used character sets. The fields requiring  transla-
       tion  include,  at  a  minimum, filenames, user names, group names, and
       link pathnames. Implementations may wish  to  have  localized  extended
       keywords that use non-portable characters.

       The standard developers considered the following options:

       o      The  archive  creator  specifies  the  well-defined  name of the
              source codeset. The receiver must  then  recognize  the  codeset
              name and perform the appropriate translations to the destination
              codeset.

       o      The archive creator includes within the  archive  the  character
              mapping  table  for  the  source codeset used to encode extended
              header records. The receiver must then read the  character  map-
              ping  table and perform the appropriate translations to the des-
              tination codeset.

       o      The archive creator translates the extended  header  records  in
              the source codeset into a canonical form. The receiver must then
              perform the appropriate translations to the destination codeset.

       The approach that incorporates the name of the source codeset poses the
       problem  of codeset name registration, and makes the archive useless to
       pax archive decoders that do not recognize that codeset.

       Because parts of an archive may be corrupted, the  standard  developers
       felt  that  including  the  character map of the source codeset was too
       fragile. The loss of this one key component could result in making  the
       entire archive useless. (The difference between this and the global ex-
       tended header decision was that the latter has a workaround-duplicating
       extended  header records on unreliable media-but this would be too bur-
       densome for large character set maps.)

       Both of the above approaches also put an undue burden on  the  pax  ar-
       chive  receiver  to handle the cross-product of all source and destina-
       tion codesets.

       To simplify the translation from the source codeset  to  the  canonical
       form  and from the canonical form to the destination codeset, the stan-
       dard developers decided that the internal representation  should  be  a
       stateless  encoding.  A  stateless encoding is one where each codepoint
       has the same meaning, without regard to the decoder being in a specific
       state.  An  example of a stateful encoding would be the Japanese Shift-
       JIS; an example of a stateless encoding would be the  ISO/IEC  646:1991
       standard (equivalent to 7-bit ASCII).

       For these reasons, the standard developers decided to adopt a canonical
       format for the representation of file information strings. The obvious,
       well-endorsed  candidate is the ISO/IEC 10646-1:2000 standard (based in
       part on Unicode), which can be used to represent the characters of vir-
       tually  all  standardized  character sets. The standard developers ini-
       tially agreed upon using UCS2 (16-bit Unicode) as the  internal  repre-
       sentation.  This  repertoire of characters provides a sufficiently rich
       set to represent all commonly-used codesets.

       However, the standard developers found that the 16-bit  Unicode  repre-
       sentation  had some problems. It forced the issue of standardizing byte
       ordering. The 2-byte length of each character made the extended  header
       records  twice as long for the case of strings coded entirely from his-
       torical 7-bit ASCII. For these reasons, the standard  developers  chose
       the UTF-8 defined in the ISO/IEC 10646-1:2000 standard. This multi-byte
       representation encodes UCS2 or UCS4 characters reliably and determinis-
       tically,  eliminating  the need for a canonical byte ordering. In addi-
       tion, NUL octets and other characters possibly confusing to POSIX  file
       systems  do not appear, except to represent themselves. It was realized
       that certain national codesets take up more space after  the  encoding,
       due  to their placement within the UCS range; it was felt that the use-
       fulness of the encoding of the names outweighs the disadvantage of size
       increase for file, user, and group names.

       The encoding of UTF-8 is as follows:

       UCS4 Hex Encoding   UTF-8 Binary Encoding
       00000000-0000007F   0xxxxxxx
       00000080-000007FF   110xxxxx 10xxxxxx
       00000800-0000FFFF   1110xxxx 10xxxxxx 10xxxxxx
       00010000-001FFFFF   11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
       00200000-03FFFFFF   111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
       04000000-7FFFFFFF   1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx

       where  each  'x' represents a bit value from the character being trans-
       lated.

   ustar Interchange Format
       The description of the ustar format reflects numerous enhancements over
       pre-1988  versions  of  the  historical  tar utility. The goal of these
       changes was not only to provide the  functional  enhancements  desired,
       but  also  to  retain  compatibility between new and old versions. This
       compatibility has been retained. Archives written using the old archive
       format are compatible with the new format.

       Implementors  should be aware that the previous file format did not in-
       clude a mechanism to archive directory type files. For this reason, the
       convention of using a filename ending with slash was adopted to specify
       a directory on the archive.

       The total size of the name and prefix fields have been set to meet  the
       minimum  requirements  for {PATH_MAX} If a pathname will fit within the
       name field, it is recommended that the pathname be stored there without
       the use of the prefix field. Although the name field is known to be too
       small to contain {PATH_MAX} characters, the value was  not  changed  in
       this version of the archive file format to retain backwards-compatibil-
       ity, and instead the prefix was introduced. Also, because of  the  ear-
       lier  version  of the format, there is no way to remove the restriction
       on the linkname field being limited in size to just that  of  the  name
       field.

       The  size  field is required to be meaningful in all implementation ex-
       tensions, although it could be zero. This is required so that the  data
       blocks can always be properly counted.

       It  is  suggested  that  if device special files need to be represented
       that cannot be represented in the standard format, that one of the  ex-
       tension  types  (A-Z)  be used, and that the additional information for
       the special file be represented as data and be reflected  in  the  size
       field.

       Attempting to restore a special file type, where it is converted to or-
       dinary data and conflicts with an existing filename, need not  be  spe-
       cially  detected by the utility. If run as an ordinary user, pax should
       not be able to overwrite the entries in, for example, /dev in any  case
       (whether  the  file  is  converted to another type or not). If run as a
       privileged user, it should be able to do so, and it would be considered
       a  bug if it did not. The same is true of ordinary data files and simi-
       larly named special files; it is impossible to anticipate the needs  of
       the user (who could really intend to overwrite the file), so the behav-
       ior should be predictable (and thus regular) and rely on the protection
       system as required.

       The  value 7 in the typeflag field is intended to define how contiguous
       files can be stored in a ustar archive.  IEEE Std 1003.1-2001 does  not
       require  the  contiguous file extension, but does define a standard way
       of archiving such files so that all conforming  systems  can  interpret
       these  file  types  in  a meaningful and consistent manner. On a system
       that does not support extended file types, the pax  utility  should  do
       the best it can with the file and go on to the next.

       The  file  protection  modes are those conventionally used by the ls(1)
       utility. This is extended beyond the usage in the ISO POSIX-2  standard
       to  support  the "shared text" or "sticky" bit. It is intended that the
       conformance document should not document anything beyond the  existence
       of  and  support  of  such  a mode.  Further extensions are expected to
       these bits, particularly with  overloading  the  set-user-ID  and  set-
       group-ID flags.

   cpio Interchange Format
       The  reference to appropriate privilege in the cpio format refers to an
       error on standard output; the ustar format  does  not  make  comparable
       statements.

       The  model for this format was the historical System V cpio -c data in-
       terchange format. This model documents the portable version of the cpio
       format  and  not the binary version. It has the flexibility to transfer
       data of any type described within IEEE Std 1003.1-2001, yet is extensi-
       ble  to  transfer  data  types  specific  to extensions beyond IEEE Std
       1003.1-2001 (for example, contiguous files). Because it  describes  ex-
       isting  practice,  there is no question of maintaining upwards-compati-
       bility.

   cpio Header
       There has been some concern that the size of the  c_ino  field  of  the
       header  is too small to handle those systems that have very large inode
       numbers. However, the c_ino field in the header is used strictly  as  a
       hard-link  resolution mechanism for archives. It is not necessarily the
       same value as the inode number of the file in the location  from  which
       that file is extracted.

       The name c_magic is based on historical usage.

   cpio Filename
       For  most  historical  implementations  of the cpio utility, {PATH_MAX}
       octets can be used to describe the pathname without the addition of any
       other  header  fields  (the  NUL  character  would  be included in this
       count).  {PATH_MAX} is the minimum value for pathname size,  documented
       as  256  bytes. However, an implementation may use c_namesize to deter-
       mine the exact length of the pathname.  With the current description of
       the  <cpio.h>  header,  this  pathname size can be as large as a number
       that is described in six octal digits.

       Two values are documented under the c_mode field values to provide  for
       extensibility for known file types:

       0110 000
              Reserved  for contiguous files. The implementation may treat the
              rest of the information for this archive like a regular file. If
              this  file  type is undefined, the implementation may create the
              file as a regular file.

       This provides for extensibility of the cpio format while  allowing  for
       the  ability to read old archives. Files of an unknown type may be read
       as "regular files" on some implementations. On a system that  does  not
       support  extended file types, the pax utility should do the best it can
       with the file and go on to the next.

FUTURE DIRECTIONS
       None.

End of informative sections.
_________________________________________________________________

SEE ALSO
       Shell Command Language, cp(1), ed(1), getopts(1), ls(1), printf(3), the
       Base  Definitions  volume of IEEE Std 1003.1-2001, <cpio.h>, the System
       Interfaces  volume  of  IEEE  Std  1003.1-2001,   chown(2),   creat(2),
       mkdir(2), mkfifo(2), stat(2), utime(2), write(2).

CHANGE HISTORY
       First released in Issue 4.

   Issue 5
       A  note  is added to the APPLICATION USAGE indicating that the cpio and
       tar formats can only support files up to 8 gigabytes in size.

   Issue 6
       The pax utility is aligned with the IEEE P1003.2b draft standard:

       o      Support has been added for symbolic links in the options and in-
              terchange formats.

       o      A new format has been devised, based on extensions to ustar.

       o      References  to  the "extended" tar and cpio formats derived from
              the POSIX.1-1990 standard have been changed to remove  the  "ex-
              tended"  adjective  because  this could cause confusion with the
              extended tar header added in this revision. (All  references  to
              tar are actually to ustar.)

       The TZ entry is added to the ENVIRONMENT VARIABLES section.

       IEEE  PASC  Interpretation  1003.2  #168  is  applied,  clarifying that
       mkdir(2) and mkfifo(2) calls can ignore an [EEXIST] error when extract-
       ing an archive.

       IEEE  PASC  Interpretation  1003.2  #180 is applied, clarifying how ex-
       tracted files are created when in read mode.

       IEEE PASC Interpretation 1003.2 #181 is  applied,  clarifying  the  de-
       scription of the -t option.

       IEEE PASC Interpretation 1003.2 #195 is applied.

       IEEE  PASC  Interpretation  1003.2 #206 is applied, clarifying the han-
       dling of links for the -H, -L, and -l options.

       IEEE Std 1003.1-2001/Cor 1-2002, item XCU/TC1/D6/35 is applied,  adding
       the process ID of the pax process into certain fields. This change pro-
       vides a method for the implementation  to  ensure  that  different  in-
       stances  of  pax extracting a file named /a/b/foo will not collide when
       processing the extended header information associated with foo.

       IEEE Std 1003.1-2001/Cor 1-2002, item XCU/TC1/D6/36 is applied,  chang-
       ing -x B to -x pax in the OPTIONS section.

       IEEE  Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/20 is applied, updat-
       ing the SYNOPSIS to be consistent with the normative text.

       IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/21 is applied,  updat-
       ing  the  DESCRIPTION  to describe the behavior when files to be linked
       are symbolic links and the system is not capable of making  hard  links
       to symbolic links.

       IEEE  Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/22 is applied, updat-
       ing the OPTIONS section to describe the behavior for how  multiple  op-
       tions are to be handled.

       IEEE  Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/23 is applied, updat-
       ing the write option within the OPTIONS section.

       IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/24 is applied,  adding
       a  paragraph  into the OPTIONS section that states that specifying more
       than one of the mutually-exclusive options (-H and -L) is  not  consid-
       ered an error and that the last option specified will determine the be-
       havior of the utility.

       IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/25 is applied,  remov-
       ing  the  ctime  paragraph within the EXTENDED DESCRIPTION.  There is a
       contradiction in the definition of the ctime keyword for  the  pax  ex-
       tended  header,  in that the st_ctime member of the stat structure does
       not refer to a file creation time. No field in the standard stat struc-
       ture from <sys/stat.h> includes a file creation time.

       IEEE  Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/26 is applied, making
       it clear that typeflag 1 RB ( ustar  Interchange  Format)  applies  not
       only  to files that are hard-linked, but also to files that are aliased
       via symlinks.

       IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/27 is applied,  clari-
       fying the cpio c_nlink field.

       End of quoted text from the POSIX.1-2001 standard.

OTHER OPTIONS
       The  following  other options are implemented as extension to the POSIX
       standard.  Note that some other  non-POSIX  options  are  mentioned  in
       -help  and  -xhelp output - these are also supported in spax(1) and are
       described in the star(1) manual page.

       -help  Prints a summary of the most important options for  spax(1)  and
              exits.

       -do-statistics
              Print statistic messages at the end of a spax(1) run.

       -xhelp Prints  a  summary of the less important options for spax(1) and
              exits.

       -version
              Prints the spax version number string and exists.

EXAMPLES
ENVIRONMENT
FILES
SEE ALSO
DIAGNOSTICS
NOTES
       The Institute of Electrical and  Electronics  Engineers  and  The  Open
       Group, have given us permission to reprint portions of their documenta-
       tion. In the following statement, the phrase ``this  text''  refers  to
       portions of the system documentation.

       Portions  of  this text are reprinted and reproduced in electronic form
       in the sfind manual, from IEEE Std 1003.1, 2004 Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX),
       The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004  by
       the Institute of Electrical and Electronics Engineers, Inc and The Open
       Group. In the event of any discrepancy between these versions  and  the
       original  IEEE  and  The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard  can
       be obtained online at http://www.opengroup.org/unix/online.html.

BUGS
AUTHOR
       Joerg Schilling
       Seestr. 110
       D-13353 Berlin
       Germany

       Mail bugs and suggestions to:

       schilling@fokus.fraunhofer.de     or    js@cs.tu-berlin.de    or    jo-
       erg@schily.isdn.cs.tu-berlin.de

Joerg Schilling                    13/04/16                           SPAX(1L)

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