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pax

PAX(1)			FreeBSD General Commands Manual 		PAX(1)

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

SYNOPSIS
     pax [-cdnvz] [-f archive] [-s replstr] ... [-U user] ... [-G group] ...
	 [-T [from_date] [,to_date]] ... [pattern ...]
     pax -r [-cdiknuvzDYZ] [-f archive] [-o options] ... [-p string] ...
	 [-s replstr] ... [-E limit] [-U user] ... [-G group] ... [-T
	 [from_date] [,to_date]] ... [pattern ...]
     pax -w [-dituvzHLPX] [-b blocksize] [[-a] [-f archive]] [-x format]
	 [-s replstr] ... [-o options] ... [-U user] ... [-G group] ...
	 [-B bytes] [-T [from_date] [,to_date] [/[c][m]]] ... [file ...]
     pax -r -w [-diklntuvDHLPXYZ] [-p string] ... [-s replstr] ... [-U user]
	 ... [-G group] ... [-T [from_date] [,to_date] [/[c][m]]] ...
	 [file ...] directory

DESCRIPTION
     The pax utility will read, write, and list the members of an archive
     file, and will copy directory hierarchies.  These operations are indepen-
     dent of the specific archive format, and support a wide variety of dif-
     ferent archive 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 follow-
     ing functional modes pax will operate under: list, read, write, and copy.

       List.  Write to standard output a table of contents of the mem-
	     bers of the archive file read from standard input, whose path-
	     names match the specified patterns.  The table of contents con-
	     tains one filename per line and is written using single line
	     buffering.

     -r      Read.  Extract the members of the archive file read from the
	     standard input, with pathnames matching the specified patterns.
	     The archive format and blocking is automatically determined on
	     input.  When an extracted file is a directory, the entire file
	     hierarchy rooted at that directory is extracted.  All extracted
	     files are created relative to the current file hierarchy.	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.  Write an archive containing the file operands to standard
	     output using the specified 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.

     -r -w   Copy.  Copy 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 direc-
	     tory will be included.  The effect of the copy is as if the
	     copied files were written to an archive file and then subse-
	     quently 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 pos-
     sible (see the -E option for more details on error handling).

OPERANDS
     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 nota-
     tion described by fnmatch(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 mem-
     ber, pax will write these file operand pathnames in a diagnostic message
     to standard error and then exit with a non-zero exit status.

OPTIONS
     The following options are supported:

     -r    Read an archive file from standard input and extract the specified
	   files.  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 ar-
	   chive 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 completion of operation.

     -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
	   .

     -a    Append files to the end of an archive that was previously written.
	   If an archive 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 vol-
	   ume 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 opera-
	   tions 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 sup-
	   port an append operation.

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

     -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.

     -i    Interactively rename files or archive members.  For each archive
	   member matching a pattern operand or each file matching a file op-
	   erand, pax will prompt to /dev/tty giving the name of the file, its
	   file mode and its modification time.  The pax utility will then
	   read a line from /dev/tty.  If this line is blank, the file or ar-
	   chive 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.  The pax utility will immediately exit with a non-zero exit
	   status if  is encountered when reading a response or if
	   /dev/tty cannot be opened for reading and writing.

     -k    Do not overwrite existing files.

     -l    Link files.	(The letter ell).  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 hierarchy rooted at
	   that directory is also matched (unless -d is also specified).

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

     -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 charac-
	   teristics 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.  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 privi-
	       leges, in order to preserve all aspects of the files as they
	       are recorded in the archive.  The e flag is the sum of the o
	       and p flags.

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

	   o   Preserve the user ID and group ID.

	   p   `Preserve' the file mode bits.  This intended to be used by a
	       user with regular privileges who wants to preserve all aspects
	       of the file other than the ownership.  The file times are pre-
	       served 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 cre-
	   ation 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 characteristic 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 modification times are still preserved.

     -s replstr
	   Modify the file or archive member names specified by the pattern or
	   file operands according to the substitution expression replstr,
	   using the syntax of the ed(1) utility regular expressions.  The
	   format of these regular expressions are:
		 /old/new/[gp]
	   As in ed(1), old is a basic regular expression and new can contain
	   an ampersand (&), \n (where n is a digit) back-references, or
	   subexpression matching.  The old string may also contain 
	   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 com-
	   mand line, terminating with the first successful substitution.  The
	   optional trailing g continues to apply the substitution expression
	   to the pathname substring which starts with the first character
	   following the end of the last successful substitution.  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 for-
	   mat:
		  >> 
	   File or archive member names that substitute to the empty string
	   are not selected and will be skipped.

     -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    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 desti-
	   nation 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:
		  == 
	   For pathnames representing a symbolic link, the output has the for-
	   mat:
		  => 
	   Where  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  as soon
	   as processing begins on that file or archive member.  The trailing
	   , is not buffered, and is written only after the file has
	   been read or written.

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

	   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 informa-
		    tion 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.

	   bcpio    The old binary cpio format.  The default blocksize for
		    this format is 5120 bytes.	This format is not very porta-
		    ble and should not be used when other formats are avail-
		    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.

	   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.  Pathnames stored by this
		    format must be 250 characters or less in length.

	   The pax utility 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.

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

     -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 multi-
	   plication by 1048576 (1M), 1024 (1K) or 512, respectively.  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 recom-
	   mended.

     -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 destination directory.

     -E limit
	   Limit the number of consecutive read faults while trying to read a
	   flawed archives 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.

     -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.

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

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

     -T [from_date][,to_date][/[c][m]]
	   Allow files to be selected based on a file modification or inode
	   change time falling within a specified time range of from_date to
	   to_date (the dates are inclusive).  If only a from_date is sup-
	   plied, 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 modification 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 create 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:
		 [yy[mm[dd[hh]]]]mm[.ss]
	   Where 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), the second 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.
	   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.

     -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.

     -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 information about
	   device ID's.

     -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 modifica-
	   tion time is checked using the pathname created after all the file
	   name modifications have completed.

     The options that operate on the names of files or archive members (-c,
     -i, -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 members 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 considered selected unless it is newer than the
     file to which it is compared.

EXIT STATUS
     The pax utility will exit with one of the following values:

     0	 All files were processed successfully.

     1	 An error occurred.

EXAMPLES
     The command:
	   pax -w -f /dev/sa0 .
     copies the contents of the current directory to the device /dev/sa0.

     The command:
	   pax -v -f filename
     gives the verbose table of contents for an archive stored in filename.

     The following commands:
	   mkdir /tmp/to
	   cd /tmp/from
	   pax -rw . /tmp/to
     will copy the entire /tmp/from directory hierarchy to /tmp/to.

     The command:
	   pax -r -s ',^//*usr//*,,' -f a.pax
     reads the archive a.pax, with all files rooted in ``/usr'' into the ar-
     chive extracted relative to the current directory.

     The command:
	   pax -rw -i . dest_dir
     can be used to interactively select the files to copy from the current
     directory to dest_dir.

     The command:
	   pax -r -pe -U root -G bin -f a.pax
     will extract all files from the archive a.pax which are owned by root
     with group bin and will preserve all file permissions.

     The command:
	   pax -r -w -v -Y -Z home /backup
     will 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.

DIAGNOSTICS
     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 processing 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 partially 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 diagnostic 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)

STANDARDS
     The pax utility is a superset of the IEEE Std 1003.2 (``POSIX.2'') stan-
     dard.  The options -z, -B, -D, -E, -G, -H, -L, -P, -T, -U, -Y, -Z, the
     archive formats bcpio, sv4cpio, sv4crc, tar, and the flawed archive han-
     dling during list and read operations are extensions to the POSIX stan-
     dard.

HISTORY
     The pax utility appeared in 4.4BSD.

AUTHORS
     Keith Muller at the University of California, San Diego

BUGS
     The pax utility does not recognize multibyte characters.

FreeBSD 6.1			 July 3, 2004			   FreeBSD 6.1