spax



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




NAME

       pax - portable archive interchange


SYNOPSIS

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

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

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

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


DESCRIPTION

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

                        The Open Group Base Specifications Issue 6
                               IEEE Std 1003.1, 2004 Edition
          Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.
         ------------------------------------------------------------------------

       DESCRIPTION

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

            The action to be taken depends on the presence of the -r and -w
            options. 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 directory 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 attempt 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,
                 except 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 extract 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:

               * The intermediate directory used as the path argument

               * 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.

            A single archive can span multiple files. The pax utility shall
            determine, 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 symbolic links and the system is not capable of making
            hard links to symbolic 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 previously
            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.

            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
                 format.
            -a   Append files to the end of the archive. It is
                 implementation-defined 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 creating 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
                 archive 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
                 specified 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 symbolic 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 operand, 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 contents 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 writing.

                 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 symbolic 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
                 specified 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
                 operand. 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
                 algorithm 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
                      follow 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
                 application 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 ignored. 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 indicated:

                 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 performed using the pattern matching notation
                      described in Patterns Matching a Single Character and
                      Patterns Matching Multiple Characters. For example:

                      -o delete=security.*

                      would suppress security-related information. See pax
                      Extended 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
                      allows user control over the name that is written into
                      the ustar header blocks for the extended header produced
                      under 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
                      results.

                      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
                      control 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
                      results.

                      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
                      environment variable. If TMPDIR is not set, pax shall
                      use /tmp.

                 invalid=action
                      (Applicable only to the -x pax format.) This keyword
                      allows user control over the action pax takes upon
                      encountering 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
                           destination hierarchy. (For example, the name may
                           contain embedded NULs.)

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

                         + In list mode, any character string value (filename,
                           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
                      argument 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
                           filename, 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
                      existing files that may be allowed by the -o invalid=
                      actions 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
                      ambiguity, the listopt= format shall be the only or
                      final keyword= value pair in a -o option-argument; all
                      characters 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, evaluated 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
                      extended header records for each file. See pax Extended
                      Header File Times.

                 In addition to these keywords, if the -x pax format is
                 specified, 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 included. Multiple characteristics can be concatenated
                 within the same string and multiple -p options can be
                 specified. The meaning 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
                      characteristics.
                 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,
                 subject to the permissions of the invoking process. The
                 access and modification times of the file shall be preserved
                 unless otherwise 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-arguments 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
                 operands 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, ’0 (where n is a digit)
                 backreferences, or subexpression matching. The old string
                 shall also be permitted 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
                 modification 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 member is newer than the file. In write mode, an
                 archive file member with the same name as a file in the file
                 system shall be superseded if the file is newer than the
                 archive member. If -a is also specified, this is accomplished
                 by appending to the archive; otherwise, it is unspecified
                 whether this is accomplished by actual replacement in the
                 archive or by appending to the archive. 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 hierarchy is
                 newer.
            -v   In list mode, produce a verbose table of contents (see the
                 STDOUT section). Otherwise, write archive member pathnames to
                 standard 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 character special archive files shall be
                      5120. Implementations 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
                      character special archive files shall be 5120.
                      Implementations 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
                      character special archive files shall be 10240.
                      Implementations 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 immediately 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

            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 argument shall be used as the format string
            described in the Base Definitions 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, 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
                 keywords:
                    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
                      addition to the form required by Values for cpio c_mode
                      Field.

                    o Any keyword defined for the extended header in pax
                      Extended Header.

                    o Any keyword provided as an implementation-defined
                      extension 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
                 translated from the UTF-8 encoding to the character set
                 appropriate for the local file system, user database, and so
                 on, as applicable.

            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 subformat 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
                 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
                 preceded by a sequence of comma-separated keywords:

                 (keyword[,keyword] ... )

                 The values for all the keywords that are non-null shall be
                 concatenated 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 ,
                 including 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
            operands are specified. It shall be a text file containing a list
            of pathnames, 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 according 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 determine 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
                 pattern 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_MESSAGES 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_MESSAGES 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 diagnostic 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 unspecified 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 EXTENDED DESCRIPTION section, or some other
            implementation-defined format (see -x format).

            In list mode, when the -o listopt= format has been specified, the
            selected 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 selected archive members shall be written to
            standard output using the following format:

            "%s0, <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
            archive:

            "%s[Image]==[Image]%s0, <ls -l listing>, <linkname>

            For all other pathnames:

            "%s0, <ls -l listing>

            where <ls  -l listing> shall be the format specified by the ls
            utility 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 number 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:

            "%s0, <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
            trailing ’p’, substitutions shall be written to standard error in
            the following format:

            "%s[Image]>>[Image]%s0, <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
            unspecified 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 extended 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), modification 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 identical to the ustar format described in ustar
            Interchange Format. Each file archived shall be represented by the
            following sequence:

               * 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.

               * A header block that describes the file. Any fields in the
                 preceding optional extended header shall override the
                 associated fields in this header block for this file.

               * 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 example, the second file in the archive has no
            extended header preceding it, presumably because it has no need
            for extended attributes.

                 [Image]

                            Figure: pax Format Archive Example

            pax Header Block

            The pax header block shall be identical to the ustar header block
            described in ustar Interchange Format , except that two additional
            typeflag values are defined:

            x    Represents extended header records for the following file in
                 the archive (which shall have its own ustar header block).
                 The format of these extended header records shall be as
                 described in 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
            extended 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. Therefore, header block field values should be selected to
            provide reasonable 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 created by pax -o linkdata shall include these data
            blocks with the hard links.

            pax Extended Header

            A pax extended header contains values that are inappropriate for
            the ustar header block because of limitations in that format:
            fields requiring 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 requirements of the ustar header. The values
            in an extended header add attributes to the following file (or
            files; see the description of the typeflag g header block) or
            override values in the following header block(s), as indicated in
            the following list of keywords.

            An extended header shall consist of one or more records, each
            constructed as follows:

            "%d %s=%s0, <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 consisting 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 extended 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() 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 described 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
                 defined to refer to known standards; additional names may be
                 agreed on between the originator and recipient.
                                   <value>                   Formal Standard

                  ISO-IR[Image]646[Image]1990               ISO/IEC 646:1990

                  ISO-IR[Image]8859[Image]1[Image]1998      ISO/IEC
                                                            8859-1:1998

                  ISO-IR[Image]8859[Image]2[Image]1999      ISO/IEC
                                                            8859-2:1999

                  ISO-IR[Image]8859[Image]3[Image]1999      ISO/IEC
                                                            8859-3:1999

                  ISO-IR[Image]8859[Image]4[Image]1998      ISO/IEC
                                                            8859-4:1998

                  ISO-IR[Image]8859[Image]5[Image]1999      ISO/IEC
                                                            8859-5:1999

                  ISO-IR[Image]8859[Image]6[Image]1999      ISO/IEC
                                                            8859-6:1999

                  ISO-IR[Image]8859[Image]7[Image]1987      ISO/IEC
                                                            8859-7:1987

                  ISO-IR[Image]8859[Image]8[Image]1999      ISO/IEC
                                                            8859-8:1999

                  ISO-IR[Image]8859[Image]9[Image]1999      ISO/IEC
                                                            8859-9:1999

                  ISO-IR[Image]8859[Image]10[Image]1998     ISO/IEC
                                                            8859-10:1998

                  ISO-IR[Image]8859[Image]13[Image]1998     ISO/IEC
                                                            8859-13:1998

                  ISO-IR[Image]8859[Image]14[Image]1998     ISO/IEC
                                                            8859-14:1998

                  ISO-IR[Image]8859[Image]15[Image]1999     ISO/IEC
                                                            8859-15:1999

                  ISO-IR[Image]10646[Image]2000             ISO/IEC
                                                            10646:2000

                  ISO-IR[Image]10646[Image]2000[Image]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 indicates 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 translate the name from the UTF-8 encoding in the
                 header record to the character set appropriate for the group
                 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 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
                 following ustar header block shall determine the type of link
                 created. 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 (contents of the symbolic link) 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
                 linkpath extended header record for each link whose pathname
                 cannot be represented entirely 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() 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 appropriate 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
                 override 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
                 extended header record for each file whose pathname cannot be
                 represented 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 extended 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
                 using 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 attributes
                 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 affected
                 attribute shall be assigned the <value>. When extended 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 ustar
                 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 exactly 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 second 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 supports 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, followed 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 logical records
            filled with binary zeros, interpreted as an end-of-archive
            indicator.

            The logical records may be grouped for physical I/O operations, as
            described under the -b blocksize and -x ustar options. Each group
            of logical records may be written with a single operation
            equivalent to the write() 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
            system 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
            terminated by a NUL character. The fields name, linkname, and
            prefix are NUL-terminated character strings except when all
            characters in the array contain non-NUL characters including the
            last character. The version 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 standard 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
            produce 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
            standard octal digit representation. The encoded bits shall
            represent the following values:

                                  Table: ustar mode Field
                Bit    IEEE Std 1003.1-2001 Bit          Description
               Value

             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 appropriate privilege, the mode bits for which the user
            does not have appropriate privilege shall be ignored. Some of the
            mode bits in the archive 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
            number 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() function.

            The chksum field shall be the ISO/IEC 646:1991 standard IRV
            representation 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 unsigned value. These values shall be added to an
            unsigned integer, initialized 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 conversion to a regular file occurs, the
            pax utility shall produce an error 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
                 typeflag value of binary zero ( ’ ’ ) 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 regular files with a typeflag value of the
                 ISO/IEC 646:1991 standard IRV ’0’.
            1    Represents a file linked to another file, of any type,
                 previously archived. Such files are identified by having the
                 same device and file serial numbers, and pathnames that refer
                 to different 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
                 respectively. 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.
                 Implementations may map the device specifications to their
                 own local specification or may ignore the entry.
            5    Specifies a directory or subdirectory. On systems where disk
                 allocation 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
                 associated some high-performance attribute. Implementations
                 without such extensions should treat this file as a regular
                 file (type 0).
            A-Z  The letters ’A’ to ’Z’, inclusive, are reserved for custom
                 implementations. 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 extract both pathnames from the resulting archive
            will always cause an error (unless the -u option is used) because
            the link cannot be created.

            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
            produce a diagnostic message. Handling of other file types is
            implementation-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 uname and gname fields shall contain the
            ISO/IEC 646:1991 standard IRV representation of the owner and
            group of the file, respectively (truncated to fit, if necessary).
            When the file is restored by a privileged, protection-preserving
            version of the utility, the user and group databases shall be
            scanned for these names. If found, the user and group IDs
            contained within these files shall be used rather than the values
            contained within the uid and gid fields.

            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
            information 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 appending 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
                 containing the identifying value "070707".
            c_dev, c_ino
                 Contains values that uniquely identify the file within the
                 archive (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                040000  Directory

                     C_ISFIFO               010000  FIFO

                     C_ISREG                0100000 Regular file

                     C_ISLNK                0120000 Symbolic link

                     C_ISBLK                060000  Block special file

                     C_ISCHR                020000  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 calculating 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
            pathname, 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 previously 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 implementation-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.
            Interpretation 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:

               * 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.

               * 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.

               * If a user does not have appropriate privilege to set a
                 particular 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 unspecified 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 undefined.

       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 values as
            an unrelated file in the existing part of the archive. Also, when
            (intentionally) appending additional links to a file in the
            existing 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
            between historical tar and cpio implementations. In particular,
            the two utilities use -m in diametrically opposed ways. The -p
            option also provides a consistent means of extending the ways in
            which future file attributes 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
                 superuser, someone with all the appropriate privileges, to
                 preserve all aspects of the files as they are recorded in the
                 archive. The e flag is the sum of o and p, and other
                 implementation-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 usage of pax within shell scripts. This
            problem is inherited from historical 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.
            Specifically, 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 permissions on the first version of the file do not permit
            it to be overwritten.

            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 historical 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%(size)D28.7’      -o listopt=’(name)s28(atime)T28T’

            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
            represents a peaceful compromise between advocates of the
            historical tar and cpio utilities.

            A fundamental difference between cpio and tar was in the way
            directories were treated. The cpio utility did not treat
            directories differently from other files, and to select a
            directory and its contents required 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 requirement. 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 default, 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
            specification character, has the "appropriate privilege" to
            restore full ownership 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() 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
            extracting files with permissions that are different from those
            that existed at the time the archive was created. When extracting
            sensitive information into a directory hierarchy that no longer
            exists, users are encouraged to set their file creation mask
            appropriately to protect these files during extraction.

            The table of contents output is written to standard output to
            facilitate 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 provide this capability as an extension. If there
            are hard links to symbolic 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
            certain 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 (215-512 bytes) is the
            largest multiple of 512 bytes that fits into a signed 16-bit tape
            controller transfer register. There are known limitations in some
            historical systems that would prevent larger blocks from being
            accepted. Historical values were chosen to improve compatibility
            with historical scripts using dd or similar utilities to
            manipulate 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 advantage 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 performance advantages over historical
            implementations. The -n option in early proposals had three
            effects; the first was to cause special characters 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
            behavior is retained by this volume of IEEE Std 1003.1-2001, for
            many reasons. 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 diagnostic
            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 utility. Both
            methods are historical practice: cp provides a simpler, more
            intuitive interface, 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 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 applications 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
            implementations provide informative messages to the user on
            standard error 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 complement 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
            access 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
            historical 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
            functionality. 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
            portability 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 example, 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 retained.

            It is required that extracted directories, by default, have their
            access 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 permissions may not permit file creation. One
            possible solution is to create directories with the mode specified
            in the archive, as modified by the umask of the user, with
            sufficient permissions to allow file creation. 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
            defined by the printf utility. However, since there is no separate
            operand list to get conversion arguments, the format was extended
            to allow specifying the name of the conversion argument as part of
            the conversion specification.

            The T conversion specifier allows time fields to be displayed in
            any of the date formats. Unlike the ls 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/minor or file size, as with ls, 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.

            pax Interchange Format

            The new POSIX data interchange format was developed primarily to
            satisfy 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 realized that this new POSIX data interchange format
            should be very extensible because there were other requirements
            they foresaw in the near future:

               * Support international character encodings and locale
                 information

               * Support security information (ACLs, and so on)

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

               * Include data areas for implementation use

               * 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 format:

               * Encryption

               * Compression

               * Data translation between locales and codesets

               * 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:

               * 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 flexible file naming methodology, could not be
                 extended without breaking some theoretical implementation or
                 using a dummy filename that could be a legitimate filename.

               * Industry experience since the original " tar wars" fought in
                 developing 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:
            reasonable behavior when an older tar or pax utility happened to
            read an archive. 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. Making 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
            functionality 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 historically 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 information in this case. However,
            if the archive were on a reliable medium, such as a CD-ROM, the
            global extended header offers considerable potential 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 encryption 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-defined" text is included to allow
            for a system that can identify the encodings 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 practicality. 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 extensions. 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 special 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
            sufficient. 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:

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

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

               * It translates names into a portable character set and
                 identifies locale-related information, both of which are
                 probably unnecessary 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() 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
            duplicate 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
            implementations needing more than the eleven octal digits allowed
            by the ustar format. Portable file timestamps cannot be negative.
            If pax encounters 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 implementations can support finer file-time
            granularities than seconds, the normative text requires support
            only for seconds since the Epoch because the ISO POSIX-1 standard
            states them that way. The ustar format includes 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 modification
            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 included for completeness,
            allowing overrides for all of the decimal values 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, provided 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
            normative 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 extended 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
            different 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
            available 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 translation 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:

               * 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.

               * 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
                 mapping table and perform the appropriate translations to the
                 destination codeset.

               * 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 extended header decision was that the
            latter has a workaround-duplicating extended header records on
            unreliable media-but this would be too burdensome for large
            character set maps.)

            Both of the above approaches also put an undue burden on the pax
            archive receiver to handle the cross-product of all source and
            destination codesets.

            To simplify the translation from the source codeset to the
            canonical form and from the canonical form to the destination
            codeset, the standard 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 virtually all
            standardized character sets. The standard developers initially
            agreed upon using UCS2 (16-bit Unicode) as the internal
            representation. 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
            representation 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 historical 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 deterministically,
            eliminating the need for a canonical byte ordering. In addition,
            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 usefulness 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
            translated.

            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
            include 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-compatibility, and instead
            the prefix was introduced. Also, because of the earlier 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
            extensions, 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 extension 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 ordinary data and conflicts with an existing filename, need not
            be specially 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 similarly named special files; it is
            impossible to anticipate the needs of the user (who could really
            intend to overwrite the file), so the behavior 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
            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
            interchange 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 extensible to transfer data types
            specific to extensions beyond IEEE Std 1003.1-2001 (for example,
            contiguous files). Because it describes existing practice, there
            is no question of maintaining upwards-compatibility.

            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 determine 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.

       SEE ALSO

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

       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:

               * Support has been added for symbolic links in the options and
                 interchange formats.

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

               * References to the "extended" tar and cpio formats derived
                 from the POSIX.1-1990 standard have been changed to remove
                 the "extended" 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() and mkfifo() calls can ignore an [EEXIST] error when
            extracting an archive.

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

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

            IEEE PASC Interpretation 1003.2 #195 is applied.

            IEEE PASC Interpretation 1003.2 #206 is applied, clarifying the
            handling 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 provides a method for the implementation to ensure that
            different instances 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,
            changing -x B to -x pax in the OPTIONS section.

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

            IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/21 is applied,
            updating 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,
            updating the OPTIONS section to describe the behavior for how
            multiple -o delete= pattern options are to be handled.

            IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/23 is applied,
            updating 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 considered an error and that the last option
            specified will determine the behavior of the utility.

            IEEE Std 1003.1-2001/Cor 2-2004, item XCU/TC2/D6/25 is applied,
            removing the ctime paragraph within the EXTENDED DESCRIPTION.
            There is a contradiction in the definition of the ctime keyword
            for the pax extended 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 structure 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 ( 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,
            clarifying the cpio c_nlink field.

       End of informative text.
         ------------------------------------------------------------------------
                    UNIX ® is a registered Trademark of The Open Group.
                      POSIX ® is a registered Trademark of The IEEE.
                          [ Main Index | XBD | XCU | XSH | XRAT ]
         ------------------------------------------------------------------------

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


OPTIONS

       The following other options are implemented as extension to  the  POSIX
       standard:

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

       -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
       joerg@schily.isdn.cs.tu-berlin.de



Joerg Schilling                    04/09/26                           SPAX(1L)

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