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PAX(1)                    BSD General Commands Manual                   PAX(1)

NAME
     pax -- read and write file archives and copy directory hierarchies

SYNOPSIS
     pax [-0cdjnOvz] [-E limit] [-f archive] [-G group] [-s replstr] [-T range] [-U user] [pattern ...]
     pax -r [-0cDdijknOuvYZz] [-E limit] [-f archive] [-G group] [-o options] [-p string] [-s replstr]
         [-T range] [-U user] [pattern ...]
     pax -w [-0adHijLOPtuvXz] [-B bytes] [-b blocksize] [-f archive] [-G group] [-o options] [-s replstr]
         [-T range] [-U user] [-x format] [file ...]
     pax -rw [-0DdHijkLlnOPtuvXYZ] [-G group] [-p string] [-s replstr] [-T range] [-U user] [file ...]
         directory

DESCRIPTION
     pax will read, write, and list the members of an archive file and will copy directory hierarchies.  pax
     operation is independent of the specific archive format and supports a wide variety of different ar-chive archive
     chive formats.  A list of supported archive formats can be found under the description of the -x
     option.

     The presence of the -r and the -w options specifies which of the following functional modes pax will
     operate under: list, read, write, and copy.

     <none>  List.  pax will write to standard output a table of contents of the members of the archive file
             read from standard input, whose pathnames match the specified pattern arguments.  The table of
             contents contains one filename per line and is written using single line buffering.

     -r      Read.  pax extracts the members of the archive file read from the standard input, with path-names pathnames
             names matching the specified pattern arguments.  The archive format and blocking is automati-cally automatically
             cally determined on input.  When an extracted file is a directory, the entire file hierarchy
             rooted at that directory is extracted.  Extracted files are created either at absolute paths
             (those that begin with a / character) or relative to the current file hierarchy unless the -s
             option is used to remove leading slashes or add a relative path prefix.  Files being extracted
             to absolute paths may overwrite files outside of the current working directory, so care should
             be taken when extracting untrusted archives.  The setting of ownership, access and modification
             times, and file mode of the extracted files are discussed in more detail under the -p option.

     -w      Write.  pax writes an archive containing the file operands to standard output using the speci-fied specified
             fied archive format.  When no file operands are specified, a list of files to copy with one per
             line is read from standard input.  When a file operand is also a directory, the entire file
             hierarchy rooted at that directory will be included.

     -rw     Copy.  pax copies the file operands to the destination directory.  When no file operands are
             specified, a list of files to copy with one per line is read from the standard input.  When a
             file operand is also a directory the entire file hierarchy rooted at that directory will be
             included.  The effect of the copy is 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 (see the -l option below).

             Warning: The destination directory must not be one of the file operands or a member of a file
             hierarchy rooted at one of the file operands.  The result of a copy under these conditions is
             unpredictable.

     While processing a damaged archive during a read or list operation, pax will attempt to recover from
     media defects and will search through the archive to locate and process the largest number of archive
     members possible (see the -E option for more details on error handling).

     The directory operand specifies a destination directory pathname.  If the directory operand does not
     exist, or it is not writable by the user, or it is not of type directory, pax will exit with a non-zero
     exit status.

     The pattern operand is used to select one or more pathnames of archive members.  Archive members are
     selected using the pattern matching notation described by glob(3).  When the pattern operand is not
     supplied, all members of the archive will be selected.  When a pattern matches a directory, the entire
     file hierarchy rooted at that directory will be selected.  When a pattern operand does not select at
     least one archive member, pax will write these pattern operands in a diagnostic message to standard
     error and then exit with a non-zero exit status.

     The file operand specifies the pathname of a file to be copied or archived.  When a file operand does
     not select at least one archive member, pax will write these file operand pathnames in a diagnostic
     message to standard error and then exit with a non-zero exit status.

     The options are as follows:

     -0      Use the NUL (`\0') character as a pathname terminator, instead of newline (`\n').  This applies
             only to the pathnames read from standard input in the write and copy modes, and to the path-names pathnames
             names written to standard output in list mode.  This option is expected to be used in concert
             with the -print0 function in find(1) or the -0 flag in xargs(1).

     -a      Append the given file operands to the end of an archive that was previously written.  If an ar-chive archive
             chive format is not specified with a -x option, the format currently being used in the archive
             will be selected.  Any attempt to append to an archive in a format different from the format
             already used in the archive will cause pax to exit immediately with a non-zero exit status.
             The blocking size used in the archive volume where writing starts will continue to be used for
             the remainder of that archive volume.

             Warning: Many storage devices are not able to support the operations necessary to perform an
             append operation.  Any attempt to append to an archive stored on such a device may damage the
             archive or have other unpredictable results.  Tape drives in particular are more likely to not
             support an append operation.  An archive stored in a regular file system file or on a disk
             device will usually support an append operation.

     -B bytes
             Limit the number of bytes written to a single archive volume to bytes.  The bytes limit can end
             with `m', `k', or `b' to specify multiplication by 1048576 (1M), 1024 (1K) or 512, respec-tively. respectively.
             tively.  A pair of bytes limits can be separated by `x' to indicate a product.

             Warning: Only use this option when writing an archive to a device which supports an end of file
             read condition based on last (or largest) write offset (such as a regular file or a tape
             drive).  The use of this option with a floppy or hard disk is not recommended.

     -b blocksize
             When writing an archive, block the output at a positive decimal integer number of bytes per
             write to the archive file.  The blocksize must be a multiple of 512 bytes with a maximum of
             64512 bytes.  Archive block sizes larger than 32256 bytes violate the POSIX standard and will
             not be portable to all systems.  A blocksize can end with `k' or `b' to specify multiplication
             by 1024 (1K) or 512, respectively.  A pair of blocksizes can be separated by `x' to indicate a
             product.  A specific archive device may impose additional restrictions on the size of blocking
             it will support.  When blocking is not specified, the default blocksize is dependent on the
             specific archive format being used (see the -x option).

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

     -D      This option is the same as the -u option, except that the file inode change time is checked
             instead of the file modification time.  The file inode change time can be used to select files
             whose inode information (e.g., UID, GID, etc.) is newer than a copy of the file in the destina-tion destination
             tion directory.

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

     -E limit
             Limit the number of consecutive read faults while trying to read a flawed archive to limit.
             With a positive limit, pax will attempt to recover from an archive read error and will continue
             processing starting with the next file stored in the archive.  A limit of 0 will cause pax to
             stop operation after the first read error is detected on an archive volume.  A limit of NONE
             will cause pax to attempt to recover from read errors forever.  The default limit is a small
             positive number of retries.

             Warning: Using this option with NONE should be used with extreme caution as pax may get stuck
             in an infinite loop on a very badly flawed archive.

     -f archive
             Specify archive as the pathname of the input or output archive, overriding the default standard
             input (for list and read) or standard output (for write).  A single archive may span multiple
             files and different archive devices.  When required, pax will prompt for the pathname of the
             file or device of the next volume in the archive.

     -G group
             Select a file based on its group name, or when starting with a #, a numeric GID.  A `\' can be
             used to escape the #.  Multiple -G options may be supplied and checking stops with the first
             match.

     -H      Follow only command-line symbolic links while performing a physical file system traversal.

     -i      Interactively rename files or archive members.  For each archive member matching a pattern op-erand operand
             erand or each file matching a file operand, pax will prompt to /dev/tty giving the name of the
             file, its file mode, and its modification time.  pax will then read a line from /dev/tty.  If
             this line is blank, the file or archive member is skipped.  If this line consists of a single
             period, the file or archive member is processed with no modification to its name.  Otherwise,
             its name is replaced with the contents of the line.  pax will immediately exit with a non-zero
             exit status if EOF is encountered when reading a response or if /dev/tty cannot be opened for
             reading and writing.

     -j      Use bzip2 to compress (decompress) the archive while writing (reading).  The bzip2 utility must
             be installed separately.  Incompatible with -a.

     -k      Do not overwrite existing files.

     -L      Follow all symbolic links to perform a logical file system traversal.

     -l      (The lowercase letter ``ell''.)  Link files.  In the copy mode (-r -w), hard links are made
             between the source and destination file hierarchies whenever possible.

     -n      Select the first archive member that matches each pattern operand.  No more than one archive
             member is matched for each pattern.  When members of type directory are matched, the file hier-archy hierarchy
             archy rooted at that directory is also matched (unless -d is also specified).

     -O      Force the archive to be one volume.  If a volume ends prematurely, pax will not prompt for a
             new volume.  This option can be useful for automated tasks where error recovery cannot be per-formed performed
             formed by a human.

     -o options
             Information to modify the algorithm for extracting or writing archive files which is specific
             to the archive format specified by -x.  In general, options take the form: name=value.

             The following options are available for the old BSD tar format:

             nodir
             write_opt=nodir
                     When writing archives, omit the storage of directories.

     -P      Do not follow symbolic links, perform a physical file system traversal.  This is the default
             mode.

     -p string
             Specify one or more file characteristic options (privileges).  The string option-argument is a
             string specifying file characteristics to be retained or discarded on extraction.  The string
             consists of the specification characters a, e, m, o, and p.  Multiple characteristics can be
             concatenated within the same string and multiple -p options can be specified.  The meanings of
             the specification characters are as follows:

             a   Do not preserve file access times.  By default, file access times are preserved whenever
                 possible.

             e   ``Preserve everything'', the user ID, group ID, file mode bits, file access time, and file
                 modification time.  This is intended to be used by root, someone with all the appropriate
                 privileges, in order to preserve all aspects of the files as they are recorded in the ar-chive. archive.
                 chive.  The e flag is the sum of the o and p flags.

             m   Do not preserve file modification times.  By default, file modification times are preserved
                 whenever possible.

             o   Preserve the user ID and group ID.

             p   ``Preserve'' the file mode bits.  This is intended to be used by a user with regular privi-leges privileges
                 leges who wants to preserve all aspects of the file other than the ownership.  The file
                 times are preserved by default, but two other flags are offered to disable this and use the
                 time of extraction instead.

             In the preceding list, `preserve' indicates that an attribute stored in the archive is given to
             the extracted file, subject to the permissions of the invoking process.  Otherwise the
             attribute of the extracted file is determined as part of the normal file creation action.  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 will not set the S_ISUID (setuid) and S_ISGID (setgid) bits
             of the file mode.  If the preservation of any of these items fails for any reason, pax will
             write a diagnostic message to standard error.  Failure to preserve these items will affect the
             final exit status, but will not cause the extracted file to be deleted.  If the file character-istic characteristic
             istic letters in any of the string option-arguments are duplicated or conflict with each other,
             the one(s) given last will take precedence.  For example, if -p eme is specified, file modifi-cation modification
             cation times are still preserved.

     -r      Read an archive file from standard input and extract the specified file operands.  If any
             intermediate directories are needed in order to extract an archive member, these directories
             will be created as if mkdir(2) was called with the bitwise inclusive OR of S_IRWXU, S_IRWXG,
             and S_IRWXO as the mode argument.  When the selected archive format supports the specification
             of linked files and these files cannot be linked while the archive is being extracted, pax will
             write a diagnostic message to standard error and exit with a non-zero exit status at the com-pletion completion
             pletion of operation.

     -s replstr
             Modify the archive member names according to the substitution expression replstr, using the
             syntax of the ed(1) utility regular expressions.  file or pattern arguments may be given to
             restrict the list of archive members to those specified.

             The format of these regular expressions is:

                   /old/new/[gp]

             As in ed(1), old is a basic regular expression (see re_format(7)) and new can contain an amper-sand ampersand
             sand (`&'), `\n' (where n is a digit) back-references, or subexpression matching.  The old
             string may also contain newline characters.  Any non-null character can be used as a delimiter
             (`/' is shown here).  Multiple -s expressions can be specified.  The expressions are applied in
             the order they are specified on the command line, terminating with the first successful substi-tution. substitution.
             tution.

             The optional trailing g continues to apply the substitution expression to the pathname sub-string, substring,
             string, which starts with the first character following the end of the last successful substi-tution. substitution.
             tution.  The first unsuccessful substitution stops the operation of the g option.  The optional
             trailing p will cause the final result of a successful substitution to be written to standard
             error in the following format:

                   original-pathname >> new-pathname

             File or archive member names that substitute to the empty string are not selected and will be
             skipped.

     -T range
             Allow files to be selected based on a file modification or inode change time falling within the
             specified time range.  The range has the format:

                   [from_date][,to_date][/[c][m]]

             The dates specified by from_date to to_date are inclusive.  If only a from_date is supplied,
             all files with a modification or inode change time equal to or younger are selected.  If only a
             to_date is supplied, all files with a modification or inode change time equal to or older will
             be selected.  When the from_date is equal to the to_date, only files with a modification or
             inode change time of exactly that time will be selected.

             When pax is in the write or copy mode, the optional trailing field [c] [m] can be used to
             determine which file time (inode change, file modification or both) are used in the comparison.
             If neither is specified, the default is to use file modification time only.  The m specifies
             the comparison of file modification time (the time when the file was last written).  The c
             specifies the comparison of inode change time (the time when the file inode was last changed;
             e.g., a change of owner, group, mode, etc).  When c and m are both specified, then the modifi-cation modification
             cation and inode change times are both compared.

             The inode change time comparison is useful in selecting files whose attributes were recently
             changed or selecting files which were recently created and had their modification time reset to
             an older time (as what happens when a file is extracted from an archive and the modification
             time is preserved).  Time comparisons using both file times is useful when pax is used to cre-ate create
             ate a time based incremental archive (only files that were changed during a specified time
             range will be archived).

             A time range is made up of six different fields and each field must contain two digits.  The
             format is:

                   [[[[[cc]yy]mm]dd]HH]MM[.SS]

             Where cc is the first two digits of the year (the century), yy is the last two digits of the
             year, the first mm is the month (from 01 to 12), dd is the day of the month (from 01 to 31), HH
             is the hour of the day (from 00 to 23), MM is the minute (from 00 to 59), and SS is the seconds
             (from 00 to 59).  The minute field MM is required, while the other fields are optional and must
             be added in the following order: HH, dd, mm, yy, cc.

             The SS field may be added independently of the other fields.  Time ranges are relative to the
             current time, so -T 1234/cm would select all files with a modification or inode change time of
             12:34 PM today or later.  Multiple -T time range can be supplied and checking stops with the
             first match.

     -t      Reset the access times of any file or directory read or accessed by pax to be the same as they
             were before being read or accessed by pax.

     -U user
             Select a file based on its user name, or when starting with a #, a numeric UID.  A `\' can be
             used to escape the #.  Multiple -U options may be supplied and checking stops with the first
             match.

     -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.  During read, an archive member with the same name
             as a file in the file system will be extracted if the archive member is newer than the file.
             During write, a file system member with the same name as an archive member will be written to
             the archive if it is newer than the archive member.  During copy, the file in the destination
             hierarchy is 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      During a list operation, produce a verbose table of contents using the format of the ls(1)
             utility with the -l option.  For pathnames representing a hard link to a previous member of the
             archive, the output has the format:

                   ls -l listing == link-name

             For pathnames representing a symbolic link, the output has the format:

                   ls -l listing => link-name

             Where ls -l listing is the output format specified by the ls(1) utility when used with the -l
             option.  Otherwise for all the other operational modes (read, write, and copy), pathnames are
             written and flushed to standard error without a trailing newline as soon as processing begins
             on that file or archive member.  The trailing newline is not buffered and is written only after
             the file has been read or written.

     -w      Write files to the standard output in the specified archive format.  When no file operands are
             specified, standard input is read for a list of pathnames with one per line without any leading
             or trailing <blanks>.

     -X      When traversing the file hierarchy specified by a pathname, do not descend into directories
             that have a different device ID.  See the st_dev field as described in stat(2) for more infor-mation information
             mation about device IDs.

     -x format
             Specify the output archive format, with the default format being ustar.  pax currently supports
             the following formats:

             bcpio    The old binary cpio format.  The default blocksize for this format is 5120 bytes.
                      This format is not very portable and should not be used when other formats are avail-able. available.
                      able.  Inode and device information about a file (used for detecting file hard links
                      by this format), which may be truncated by this format, is detected by pax and is
                      repaired.

             cpio     The extended cpio interchange format specified in the IEEE Std 1003.2 (``POSIX.2'')
                      standard.  The default blocksize for this format is 5120 bytes.  Inode and device
                      information about a file (used for detecting file hard links by this format), which
                      may be truncated by this format, is detected by pax and is repaired.

             sv4cpio  The System V release 4 cpio.  The default blocksize for this format is 5120 bytes.
                      Inode and device information about a file (used for detecting file hard links by this
                      format), which may be truncated by this format, is detected by pax and is repaired.

             sv4crc   The System V release 4 cpio with file CRC checksums.  The default blocksize for this
                      format is 5120 bytes.  Inode and device information about a file (used for detecting
                      file hard links by this format), which may be truncated by this format, is detected by
                      pax and is repaired.

             tar      The old BSD tar format as found in 4.3BSD.  The default blocksize for this format is
                      10240 bytes.  Pathnames stored by this format must be 100 characters or less in
                      length.  Only regular files, hard links, soft links, and directories will be archived
                      (other file system types are not supported).  For backwards compatibility with even
                      older tar formats, a -o option can be used when writing an archive to omit the storage
                      of directories.  This option takes the form:

                            -o write_opt=nodir

             ustar    The extended tar interchange format specified in the IEEE Std 1003.2 (``POSIX.2'')
                      standard.  The default blocksize for this format is 10240 bytes.  Filenames stored by
                      this format must be 100 characters or less in length; the total pathname must be 255
                      characters or less.

             pax will detect and report any file that it is unable to store or extract as the result of any
             specific archive format restrictions.  The individual archive formats may impose additional
             restrictions on use.  Typical archive format restrictions include (but are not limited to):
             file pathname length, file size, link pathname length, and the type of the file.

     -Y      This option is the same as the -D option, except that the inode change time is checked using
             the pathname created after all the file name modifications have completed.

     -Z      This option is the same as the -u option, except that the modification time is checked using
             the pathname created after all the file name modifications have completed.

     -z      Use gzip(1) to compress (decompress) the archive while writing (reading).  Incompatible with
             -a.

     --insecure
             Normally pax ignores filenames or symbolic links that contain ``..'' as a path component.  With
             this option, files that contain ``..'' can be processed.

     The options that operate on the names of files or archive members (-c, -i, -j, -n, -s, -u, -v, -D, -G,
     -T, -U, -Y, and -Z) interact as follows.

     When extracting files during a read operation, archive members are `selected', based only on the user
     specified pattern operands as modified by the -c, -n, -u, -D, -G, -T, -U options.  Then any -s and -i
     options will modify in that order, the names of these selected files.  Then the -Y and -Z options will
     be applied based on the final pathname.  Finally, the -v option will write the names resulting from
     these modifications.

     When archiving files during a write operation, or copying files during a copy operation, archive mem-bers members
     bers are `selected', based only on the user specified pathnames as modified by the -n, -u, -D, -G, -T,
     and -U options (the -D option only applies during a copy operation).  Then any -s and -i options will
     modify in that order, the names of these selected files.  Then during a copy operation the -Y and the
     -Z options will be applied based on the final pathname.  Finally, the -v option will write the names
     resulting from these modifications.

     When one or both of the -u or -D options are specified along with the -n option, a file is not consid-ered considered
     ered selected unless it is newer than the file to which it is compared.

ENVIRONMENT
     TMPDIR      Path in which to store temporary files.

EXAMPLES
     Copy the contents of the current directory to the device /dev/rst_:

           $ pax -w -f /dev/rst0 .

     Give the verbose table of contents for an archive stored in filename:

           $ pax -v -f filename

     This sequence of commands will copy the entire olddir directory hierarchy to newdir:

           $ mkdir newdir
           $ cd olddir
           $ pax -rw . ../newdir

     Extract files from the archive a.pax.  Files rooted in /usr are extracted relative to the current work-ing working
     ing directory; all other files are extracted to their unmodified path.

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

     This can be used to interactively select the files to copy from the current directory to dest_dir:

           $ pax -rw -i . dest_dir

     Extract all files from the archive a.pax which are owned by root with group bin and preserve all file
     permissions:

           $ pax -r -pe -U root -G bin -f a.pax

     Update (and list) only those files in the destination directory /backup which are older (less recent
     inode change or file modification times) than files with the same name found in the source file tree
     home:

           $ pax -r -w -v -Y -Z home /backup

DIAGNOSTICS
     pax will exit with one of the following values:

           0   All files were processed successfully.

           1   An error occurred.

     Whenever 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 is written to standard error and a non-zero exit status will be returned, but pro-cessing processing
     cessing will continue.  In the case where pax cannot create a link to a file, pax will not 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 a file the user wanted.  Additionally, the file modes of extracted files
     and directories may have incorrect file bits, and the modification and access times may be wrong.

     If the creation of an archive is prematurely terminated by a signal or error, pax may have only par-tially partially
     tially created the archive, which may violate the specific archive format specification.

     If while doing a copy, pax detects a file is about to overwrite itself, the file is not copied, a diag-nostic diagnostic
     nostic message is written to standard error and when pax completes it will exit with a non-zero exit
     status.

SEE ALSO
     cpio(1), tar(1)

     "Archiving with Pax", Dru Lavigne, ONLamp.com BSD DevCenter,
     http://www.onlamp.com/pub/a/bsd/2002/08/22/FreeBSD_Basics.html

     pax(1) manual page, http://heirloom.sourceforge.net/man/pax.1.html

STANDARDS
     The pax utility is compliant with the IEEE Std 1003.1-2004 (``POSIX.1'') specification.

     The flags [-0BDEGHjLOPTUYZz], the archive formats bcpio, sv4cpio, sv4crc, tar, and the flawed archive
     handling during list and read operations are extensions to that specification.

AUTHORS
     Keith Muller at the University of California, San Diego.

BSD                            October 11, 2013                            BSD

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