PAX(1)                     OpenBSD Reference 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
     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 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.

     <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 patterns. 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 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. pax 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 di-
             rectory, the entire file hierarchy rooted at that directory will
             be included.

     -r -w   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 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 se-
     lected.  When a pattern operand does not select at least one archive mem-
     ber, 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 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 ex-
           tract 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 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 archive will be selected.  Any attempt
           to append to an archive in a format different from the format al-
           ready 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 opera-
           tions necessary to perform an append operation.  Any attempt to ap-
           pend 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 in-
           teger 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 stan-
           dard 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
           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.  Oth-
           erwise, its name is replaced with the contents of the line.  pax
           will immediately exit with a non-zero exit status if EOF is encoun-
           tered when reading a response or if /dev/tty cannot be opened for
           reading 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 character-
           istics can be concatenated within the same string and multiple -p
           options can be specified.  The meaning of the specification charac-
           ters 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 stan-
           dard 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-ar-
           guments are duplicated or conflict with each other, the one(s) giv-
           en 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, us-
           ing the syntax of the ed(1) utility regular expressions.  The for-
           mat 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 ex-
           pressions 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:
                 <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
           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:
                 <ls -l listing> == <link name>
           For pathnames representing a symbolic link, the output has the for-
           mat:
                 <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.

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

           cpio     The extended cpio interchange format specified in the IEEE
                    Std1003.2 (``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 de-
                    tected 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
                    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 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 BSD4.3.  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
                    Std1003.2 (``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.

           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.

     -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
           multiplication 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 recommend-
           ed.

     -D    This option is the same as the -u option, except that the file in-
           ode 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, 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 de-
           tected on an archive volume.  A limit of NONE will cause pax to at-
           tempt 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 op-
           tions 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
           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 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 in-
           ode 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 op-
           tions 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 de-
           vice 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 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.

EXAMPLES
     pax -w -f /dev/rst0 .

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

     pax -v -f filename

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

     mkdir newdir cd olddir pax -rw . newdir

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

     pax -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.

     pax -rw -i . dest_dir

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

     pax -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.

     pax -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.

STANDARDS
     The pax utility is a superset of the IEEE Std1003.2 (``POSIX.2'') stan-
     dard.  The options -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.

SEE ALSO
     cpio(1), tar(1)

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

ERRORS
     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 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.

OpenBSD 2.8                     April 18, 1994                               9
