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

NAME
     opax -- read and write file archives and copy directory hierarchies (OpenBSD pax implementa-
     tion)

SYNOPSIS
     opax [-0cdOnvz] [-f archive] [-s replstr] ... [-U user] ... [-G group] ... [-T [from_date]
	  [,to_date]] ... [pattern ...]
     opax -r [-cdiknuvzDOYZ] [-f archive] [-o options] ... [-p string] ... [-s replstr] ...
	  [-E limit] [-U user] ... [-G group] ... [-T [from_date] [,to_date]] ... [pattern ...]
     opax -w [-0dituvzHLOPX] [-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 ...]
     opax -r -w [-0diklntuvDHLOPXYZ] [-p string] ... [-s replstr] ... [-U user] ... [-G group]
	  ... [-T [from_date] [,to_date] [/[c][m]]] ... [file ...] directory

DESCRIPTION
     opax will read, write, and list the members of an archive file, and will copy directory
     hierarchies.  opax operation is independent of the specific archive format, and supports a
     wide variety of different 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 following functional modes
     opax will operate under: list, read, write, and copy.

     <none>  List.  opax 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 patterns.
	     The table of contents contains one filename per line and is written using single
	     line buffering.

     -r      Read.  opax extracts 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.  opax writes 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.  opax copies the file operands to the destination directory.  When no file op-
	     erands 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, opax 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 han-
     dling).

     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, opax 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 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, opax 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 op-
     erand does not select at least one archive member, opax will write these file operand path-
     names in a diagnostic message to standard error and then exit with a non-zero exit status.

     The options are as follows:

     -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 archive
	     format supports the specification of linked files and these files cannot be linked
	     while the archive is being extracted, opax will write a diagnostic message to stan-
	     dard 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 <blanks>.

     -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 ar-
	     chive will be selected.  Any attempt to append to an archive in a format different
	     from the format already used in the archive will cause opax 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 opera-
	     tion.

     -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 pathnames 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).

     -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 ar-
	     chive format being used (see the -x option).

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

     -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.

     -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, opax
	     will prompt for the pathname of the file or device of the next volume in the ar-
	     chive.

     -i      Interactively rename files or archive members.  For each archive member matching a
	     pattern operand or each file matching a file operand, opax will prompt to /dev/tty
	     giving the name of the file, its file mode, and its modification time.  opax 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.	opax 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 read-
	     ing and writing.

     -k      Do not overwrite existing files.

     -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 hierarchy rooted at that directory is also matched (unless -d is
	     also specified).

     -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.

     -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 meaning of the specification characters are as fol-
	     lows:

	     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 archive.  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 regu-
		 lar privileges who wants to preserve all aspects of the file other than the own-
		 ership.  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 speci-
	     fied, or the user ID and group ID are not preserved for any reason, opax will not
	     set the S_ISUID (setuid) and S_ISGID (setgid) bits of the file mode.  If the preser-
	     vation of any of these items fails for any reason, opax will write a diagnostic mes-
	     sage 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 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 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, termi-
	     nating 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 trail-
	     ing 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      Reset the access times of any file or directory read or accessed by opax to be the
	     same as they were before being read or accessed by opax.

     -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 ar-
	     chive 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 pre-
	     vious 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 new-
	     line as soon as processing begins on that file or archive member.	The trailing new-
	     line 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.  opax cur-
	     rently 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 information about a file (used for detecting file
		      hard links by this format) which may be truncated by this format is
		      detected by opax and is repaired.

	     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 available.  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 opax 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 opax 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 opax and is repaired.

	     tar      The old BSD tar format as found in BSD4.3.  The default blocksize for this
		      format is 10240 bytes.  Pathnames stored by this format must be 100 charac-
		      ters or less in length (including the trailing   character, which means
		      that filenames can have a maximum length of 99 characters).  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 (including the trailing   character, which means that filenames can
		      have a maximum length of 99 characters).	Pathnames (directorynames + file-
		      names) stored by this format must be 250 characters or less in length.

	     opax 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).	Incompat-
	     ible 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 multiplication by 1048576 (1M), 1024
	     (1K) or 512, respectively.  A pair of bytes limits can be separated by 'x' to indi-
	     cate 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 regu-
	     lar file or a tape drive).  The use of this option with a floppy or hard disk is not
	     recommended.

     -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 archive to
	     limit.  With a positive limit, opax will attempt to recover from an archive read
	     error and will continue processing starting with the next file stored in the ar-
	     chive.  A limit of 0 will cause opax to stop operation after the first read error is
	     detected on an archive volume.  A limit of NONE will cause opax 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 opax 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 tra-
	     versal.

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

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

     -P      Do not follow symbolic links, perform a physical file system traversal.  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 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 opax 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 opax 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 dig-
	     its.  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 dig-
	     its 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 rela-
	     tive 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 IDs.

     -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 com-
	     pleted.

     -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 com-
	     pleted.

     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, ar-
     chive 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.

ENVIRONMENT
     TMPDIR	 Path in which to store temporary files.

EXAMPLES
     $ opax -w -f /dev/rst0 .

     Copies the contents of the current directory to the device /dev/rst0.

     $ opax -v -f filename

     Gives the verbose table of contents for an archive stored in filename.

     $ mkdir newdir; cd olddir; opax -rw . newdir

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

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

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

     $ opax -rw -i . dest_dir

     Can be used to interactively select the files to copy from the current directory to
     dest_dir.

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

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

     $ opax -r -w -v -Y -Z home /backup"

     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
     opax will exit with one of the following values:

     0	 All files were processed successfully.

     1	 An error occurred.

     Whenever opax 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 opax cannot create
     a link to a file, opax 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,
     opax 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, opax may have
     only partially created the archive which may violate the specific archive format specifica-
     tion.

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

SEE ALSO
     spax(1), tar(1), bsdtar(1), star(1), cpio(1), bsdcpio(1), scpio(1)

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

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

BSD					  April 18, 1994				      BSD
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