structure and how files are named according to which directory they are
in. You should understand concepts such as standard output and standard
input, what various definitions of the term ``argument'' mean, and the
-differences between relative and absolute path names. @FIXME{and what
+differences between relative and absolute file names. @FIXME{and what
else?}
@item
This manual assumes that you are working from your own home directory
(unless we state otherwise). In this tutorial, you will create a
-directory to practice @command{tar} commands in. When we show path names,
-we will assume that those paths are relative to your home directory.
-For example, my home directory path is @file{/home/fsf/melissa}. All of
-my examples are in a subdirectory of the directory named by that path
+directory to practice @command{tar} commands in. When we show file names,
+we will assume that those names are relative to your home directory.
+For example, my home directory is @file{/home/fsf/melissa}. All of
+my examples are in a subdirectory of the directory named by that file
name; the subdirectory is called @file{practice}.
@item
@item Owner name and group separated by a slash character.
If these data are not available (for example, when listing a @samp{v7} format
-archive), numeric ID values are printed instead.
+archive), numeric @acronym{ID} values are printed instead.
@item Size of the file, in bytes.
Now @command{cd} to the directory named @file{practice}; @file{practice}
is now your @dfn{working directory}. (@emph{Please note}: Although
-the full path name of this directory is
+the full file name of this directory is
@file{/@var{homedir}/practice}, in our examples we will refer to
this directory as @file{practice}; the @var{homedir} is presumed.
names of members you identify. For example, @w{@kbd{tar --list
--file=afiles.tar apple}} would only print @file{apple}.
-Because @command{tar} preserves paths, file names must be specified as
+Because @command{tar} preserves file names, these must be specified as
they appear in the archive (i.e., relative to the directory from which
the archive was created). Therefore, it is essential when specifying
member names to @command{tar} that you give the exact member names.
@opsummary{force-local}
@item --force-local
-Forces @command{tar} to interpret the filename given to @option{--file}
+Forces @command{tar} to interpret the file name given to @option{--file}
as a local file, even if it looks like a remote tape drive name.
@xref{local and remote archives}.
@opsummary{group}
@item --group=@var{group}
-Files added to the @command{tar} archive will have a group id of @var{group},
+Files added to the @command{tar} archive will have a group @acronym{ID} of @var{group},
rather than the group from the source file. @var{group} is first decoded
as a group symbolic name, but if this interpretation fails, it has to be
-a decimal numeric group ID. @xref{override}.
+a decimal numeric group @acronym{ID}. @xref{override}.
Also see the comments for the @option{--owner=@var{user}} option.
@item --incremental
@itemx -G
-Used to inform @command{tar} that it is working with an old
+Informs @command{tar} that it is working with an old
@acronym{GNU}-format incremental backup archive. It is intended
primarily for backwards compatibility only. @xref{Incremental Dumps},
for a detailed discussion of incremental archives.
@opsummary{no-delay-directory-restore}
@item --no-delay-directory-restore
-Setting modification times and permissions of extracted
-directories when all files from this directory has been
-extracted. This is the default. @xref{Directory Modification Times and Permissions}.
+Modification times and permissions of extracted
+directories are set when all files from this directory have been
+extracted. This is the default.
+@xref{Directory Modification Times and Permissions}.
@opsummary{no-ignore-case}
@item --no-ignore-case
@opsummary{no-ignore-command-error}
@item --no-ignore-command-error
-Print warnings about subprocesses terminated with a non-zero exit
+Print warnings about subprocesses that terminated with a nonzero exit
code. @xref{Writing to an External Program}.
@opsummary{no-overwrite-dir}
@item --null
When @command{tar} is using the @option{--files-from} option, this option
-instructs @command{tar} to expect filenames terminated with @option{NUL}, so
+instructs @command{tar} to expect file names terminated with @acronym{NUL}, so
@command{tar} can correctly work with file names that contain newlines.
@xref{nul}.
When creating an archive, it is a synonym for
@option{--old-archive}. This behavior is for compatibility
with previous versions of @GNUTAR{}, and will be
-removed in the future releases.
+removed in future releases.
@xref{Changes}, for more information.
Specifies that @command{tar} should use @var{user} as the owner of members
when creating archives, instead of the user associated with the source
file. @var{user} is first decoded as a user symbolic name, but if
-this interpretation fails, it has to be a decimal numeric user ID.
+this interpretation fails, it has to be a decimal numeric user @acronym{ID}.
@xref{override}.
This option does not affect extraction from archives.
@opsummary{recursion}
@item --recursion
-With this option, @command{tar} recurses into directories.
+With this option, @command{tar} recurses into directories (default).
@xref{recurse}.
@opsummary{recursive-unlink}
@opsummary{show-omitted-dirs}
@item --show-omitted-dirs
-Instructs @command{tar} to mention directories its skipping over when
+Instructs @command{tar} to mention the directories it is skipping when
operating on a @command{tar} archive. @xref{show-omitted-dirs}.
@opsummary{show-transformed-names}
Display file or member names after applying any transformations
(@pxref{transform}). In particular, when used in conjunction with one of
-archive creation operations it instructs tar to list the member names
-stored in the archive, as opposed to the actual file
+the archive creation operations it instructs @command{tar} to list the
+member names stored in the archive, as opposed to the actual file
names. @xref{listing member and file names}.
@opsummary{sparse}
@opsummary{sparse-version}
@item --sparse-version=@var{version}
-Specified the @dfn{format version} to use when archiving sparse
+Specifies the @dfn{format version} to use when archiving sparse
files. Implies @option{--sparse}. @xref{sparse}. For the description
of the supported sparse formats, @xref{Sparse Formats}.
@opsummary{strip-components}
@item --strip-components=@var{number}
Strip given @var{number} of leading components from file names before
-extraction.@footnote{This option was called @option{--strip-path} in
-version 1.14.} For example, if archive @file{archive.tar} contained
+extraction. For example, if archive @file{archive.tar} contained
@file{/some/file/name}, then running
@smallexample
@item --verbose
@itemx -v
-Specifies that @command{tar} should be more verbose about the operations its
-performing. This option can be specified multiple times for some
-operations to increase the amount of information displayed.
+Specifies that @command{tar} should be more verbose about the
+operations it is performing. This option can be specified multiple
+times for some operations to increase the amount of information displayed.
@xref{verbose}.
@opsummary{verify}
@item --volno-file=@var{file}
Used in conjunction with @option{--multi-volume}. @command{tar} will
-keep track of which volume of a multi-volume archive its working in
+keep track of which volume of a multi-volume archive it is working in
@var{file}. @xref{volno-file}.
@opsummary{wildcards}
@ref{--portability}.
The later usage is deprecated. It is retained for compatibility with
-the earlier versions of @GNUTAR{}. In the future releases
+the earlier versions of @GNUTAR{}. In future releases
@option{-o} will be equivalent to @option{--no-same-owner} only.
@item -p @tab @ref{--preserve-permissions}.
Specifies that @command{tar} should use @var{user} as the owner of members
when creating archives, instead of the user associated with the source
file. The argument @var{user} can be either an existing user symbolic
-name, or a decimal numeric user ID.
+name, or a decimal numeric user @acronym{ID}.
There is no value indicating a missing number, and @samp{0} usually means
@code{root}. Some people like to force @samp{0} as the value to offer in
@item --group=@var{group}
@opindex group
-Files added to the @command{tar} archive will have a group id of @var{group},
+Files added to the @command{tar} archive will have a group @acronym{ID} of @var{group},
rather than the group from the source file. The argument @var{group}
-can be either an existing group symbolic name, or a decimal numeric group ID.
+can be either an existing group symbolic name, or a decimal numeric group @acronym{ID}.
@end table
@node Ignore Failed Read
The @option{--read-full-records} (@option{-B}) option is turned on by default when
@command{tar} reads an archive from standard input, or from a remote
-machine. This is because on BSD Unix systems, attempting to read a
+machine. This is because on @acronym{BSD} Unix systems, attempting to read a
pipe returns however much happens to be in the pipe, even if it is
less than was requested. If this option were not enabled, @command{tar}
would fail as soon as it read an incomplete record from the pipe.
@defvr {Backup variable} DIRLIST
-A path to the file containing the list of the file systems to backup
+The name of the file that contains a list of file systems to backup
or restore. By default it is @file{/etc/backup/dirs}.
@end defvr
@defvr {Backup variable} FILELIST
-A path to the file containing the list of the individual files to backup
+The name of the file that contains a list of individual files to backup
or restore. By default it is @file{/etc/backup/files}.
@end defvr
Name or IP address of the host machine being dumped or restored.
@item fs
-Full path name to the file system being dumped or restored.
+Full file name of the file system being dumped or restored.
@item fsname
File system name with directory separators replaced with colons. This
@multitable @columnfractions 0.20 0.60
@headitem Escape @tab Replaced with
-@item \a @tab Audible bell (ASCII 7)
-@item \b @tab Backspace (ASCII 8)
-@item \f @tab Form feed (ASCII 12)
-@item \n @tab New line (ASCII 10)
-@item \r @tab Carriage return (ASCII 13)
-@item \t @tab Horizontal tabulation (ASCII 9)
-@item \v @tab Vertical tabulation (ASCII 11)
-@item \? @tab ASCII 127
-@item \@var{n} @tab ASCII @var{n} (@var{n} should be an octal number
+@item \a @tab Audible bell (@acronym{ASCII} 7)
+@item \b @tab Backspace (@acronym{ASCII} 8)
+@item \f @tab Form feed (@acronym{ASCII} 12)
+@item \n @tab New line (@acronym{ASCII} 10)
+@item \r @tab Carriage return (@acronym{ASCII} 13)
+@item \t @tab Horizontal tabulation (@acronym{ASCII} 9)
+@item \v @tab Vertical tabulation (@acronym{ASCII} 11)
+@item \? @tab @acronym{ASCII} 127
+@item \@var{n} @tab @acronym{ASCII} @var{n} (@var{n} should be an octal number
of up to 3 digits)
@end multitable
@itemize @bullet
@item
-The main operating mode of @command{tar} does not act on a path name
-explicitly listed on the command line if one of its file name
+The main operating mode of @command{tar} does not act on a file name
+explicitly listed on the command line, if one of its file name
components is excluded. In the example above, if
you create an archive and exclude files that end with @samp{*.o}, but
explicitly name the file @samp{dir.o/foo} after all the options have been
@item Non-printable control characters:
@multitable @columnfractions 0.20 0.10 0.60
-@headitem Character @tab ASCII @tab Character name
+@headitem Character @tab @acronym{ASCII} @tab Character name
@item \a @tab 7 @tab Audible bell
@item \b @tab 8 @tab Backspace
@item \f @tab 12 @tab Form feed
@item \v @tab 11 @tab Vertical tabulation
@end multitable
-@item Space (ASCII 32)
+@item Space (@acronym{ASCII} 32)
@item Single and double quotes (@samp{'} and @samp{"})
features were implemented in a way incompatible with other archive
formats.
-Archives in @samp{gnu} format are able to hold pathnames of unlimited
+Archives in @samp{gnu} format are able to hold file names of unlimited
length.
@item oldgnu
@item The maximum length of a symbolic link is limited to 99 characters.
@item It is impossible to store special files (block and character
devices, fifos etc.)
-@item Maximum value of user or group ID is limited to 2097151 (7777777
+@item Maximum value of user or group @acronym{ID} is limited to 2097151 (7777777
octal)
@item V7 archives do not contain symbolic ownership information (user
and group name of the file owner).
This format has traditionally been used by Automake when producing
Makefiles. This practice will change in the future, in the meantime,
-however this means that projects containing filenames more than 99
+however this means that projects containing file names more than 99
characters long will not be able to use @GNUTAR{} @value{VERSION} and
Automake prior to 1.9.
@enumerate
@item The maximum length of a file name is limited to 256 characters,
-provided that the filename can be split at directory separator in
+provided that the file name can be split at a directory separator in
two parts, first of them being at most 155 bytes long. So, in most
cases the maximum file name length will be shorter than 256
characters.
@item posix
Archive format defined by @acronym{POSIX.1-2001} specification. This is the
most flexible and feature-rich format. It does not impose any
-restrictions on file sizes or filename lengths. This format is quite
+restrictions on file sizes or file name lengths. This format is quite
recent, so not all tar implementations are able to handle it properly.
However, this format is designed in such a way that any tar
implementation able to read @samp{ustar} archives will be able to read
formats:
@multitable @columnfractions .10 .20 .20 .20 .20
-@headitem Format @tab UID @tab File Size @tab Path Name @tab Devn
+@headitem Format @tab UID @tab File Size @tab File Name @tab Devn
@item gnu @tab 1.8e19 @tab Unlimited @tab Unlimited @tab 63
@item oldgnu @tab 1.8e19 @tab Unlimited @tab Unlimited @tab 63
@item v7 @tab 2097151 @tab 8GB @tab 99 @tab n/a
they occupy. Also, the @code{suid} or @code{sgid} attributes of
files are easily and silently lost when files are given away.
-When writing an archive, @command{tar} writes the user id and user name
-separately. If it can't find a user name (because the user id is not
+When writing an archive, @command{tar} writes the user @acronym{ID} and user name
+separately. If it can't find a user name (because the user @acronym{ID} is not
in @file{/etc/passwd}), then it does not write one. When restoring,
it tries to look the name (if one was written) up in
-@file{/etc/passwd}. If it fails, then it uses the user id stored in
+@file{/etc/passwd}. If it fails, then it uses the user @acronym{ID} stored in
the archive instead.
@opindex no-same-owner
@subsection Portable Names
Use portable file and member names. A name is portable if it contains
-only ASCII letters and digits, @samp{/}, @samp{.}, @samp{_}, and
+only @acronym{ASCII} letters and digits, @samp{/}, @samp{.}, @samp{_}, and
@samp{-}; it cannot be empty, start with @samp{-} or @samp{//}, or
contain @samp{/-}. Avoid deep directory nesting. For portability to
old Unix hosts, limit your file name components to 14 characters or
@command{tar} programs that follow it.
In the majority of cases, @command{tar} will be configured to create
-this format by default. This will change in the future releases, since
+this format by default. This will change in future releases, since
we plan to make @samp{POSIX} format the default.
To force creation a @GNUTAR{} archive, use option
to ignore any keywords matching the given @var{pattern} in the extended
header records. In both cases, matching is performed using the pattern
matching notation described in @acronym{POSIX 1003.2}, 3.13
-(@pxref{wildcards}). For example:
+(@pxref{wildcards}). For example:
@smallexample
--pax-option delete=security.*
@multitable @columnfractions .25 .55
@headitem Meta-character @tab Replaced By
@item %d @tab The directory name of the file, equivalent to the
-result of the @command{dirname} utility on the translated pathname.
-@item %f @tab The filename of the file, equivalent to the result
-of the @command{basename} utility on the translated pathname.
-@item %p @tab The process ID of the @command{tar} process.
+result of the @command{dirname} utility on the translated file name.
+@item %f @tab The name of the file with the directory information
+stripped, equivalent to the result of the @command{basename} utility
+on the translated file name.
+@item %p @tab The process @acronym{ID} of the @command{tar} process.
@item %% @tab A @samp{%} character.
@end multitable
@item %n @tab An integer that represents the
sequence number of the global extended header record in the archive,
starting at 1.
-@item %p @tab The process ID of the @command{tar} process.
+@item %p @tab The process @acronym{ID} of the @command{tar} process.
@item %% @tab A @samp{%} character.
@end multitable
@subsection Checksumming Problems
SunOS and HP-UX @command{tar} fail to accept archives created using
-@GNUTAR{} and containing non-ASCII file names, that
+@GNUTAR{} and containing non-@acronym{ASCII} file names, that
is, file names having characters with the eight bit set, because they
use signed checksums, while @GNUTAR{} uses unsigned
checksums while creating archives, as per @acronym{POSIX} standards. On
two's-complement base-256 notation to store values that do not fit
into standard @acronym{ustar} range. Such archives can generally be
read only by a @GNUTAR{} implementation. Moreover, they sometimes
-cannot be correctly restored on another hosts even by @GNUTAR{}. For
+cannot be correctly restored on another hosts even by @GNUTAR{}. For
example, using two's complement representation for negative time
stamps that assumes a signed 32-bit @code{time_t} generates archives
that are not portable to hosts with differing @code{time_t}
result of the @command{dirname} utility on its full name.
@item %f @tab The file name of the file, equivalent to the result
of the @command{basename} utility on its full name.
-@item %p @tab The process ID of the @command{tar} process that
+@item %p @tab The process @acronym{ID} of the @command{tar} process that
created the archive.
@item %n @tab Ordinal number of this particular part.
@end multitable
For example, if the file @file{var/longfile} was split during archive
creation between three volumes, and the creator @command{tar} process
-had process ID @samp{27962}, then the member names will be:
+had process @acronym{ID} @samp{27962}, then the member names will be:
@smallexample
var/longfile
name was @file{@var{dir}/@var{name}}, then the condensed file will be
named @file{@var{dir}/@/GNUSparseFile.@var{n}/@/@var{name}}, where
@var{n} is a decimal number@footnote{technically speaking, @var{n} is a
-@dfn{process ID} of the @command{tar} process which created the
+@dfn{process @acronym{ID}} of the @command{tar} process which created the
archive (@pxref{PAX keywords}).}.
To expand a version 1.0 file, run @command{xsparse} as follows:
@FIXME{Reorganize the following material}
The @command{cpio} archive formats, like @command{tar}, do have maximum
-pathname lengths. The binary and old ASCII formats have a max path
-length of 256, and the new ASCII and CRC ASCII formats have a max
-path length of 1024. @acronym{GNU} @command{cpio} can read and write archives
-with arbitrary pathname lengths, but other @command{cpio} implementations
+file name lengths. The binary and old @acronym{ASCII} formats have a maximum file
+length of 256, and the new @acronym{ASCII} and @acronym{CRC ASCII} formats have a max
+file length of 1024. @acronym{GNU} @command{cpio} can read and write archives
+with arbitrary file name lengths, but other @command{cpio} implementations
may crash unexplainedly trying to read them.
-@command{tar} handles symbolic links in the form in which it comes in BSD;
+@command{tar} handles symbolic links in the form in which it comes in @acronym{BSD};
@command{cpio} doesn't handle symbolic links in the form in which it comes
in System V prior to SVR4, and some vendors may have added symlinks
to their system without enhancing @command{cpio} to know about them.
Others may have enhanced it in a way other than the way I did it
at Sun, and which was adopted by AT&T (and which is, I think, also
present in the @command{cpio} that Berkeley picked up from AT&T and put
-into a later BSD release---I think I gave them my changes).
+into a later @acronym{BSD} release---I think I gave them my changes).
(SVR4 does some funny stuff with @command{tar}; basically, its @command{cpio}
can handle @command{tar} format input, and write it on output, and it
@command{cpio} handles special files; traditional @command{tar} doesn't.
-@command{tar} comes with V7, System III, System V, and BSD source;
-@command{cpio} comes only with System III, System V, and later BSD
+@command{tar} comes with V7, System III, System V, and @acronym{BSD} source;
+@command{cpio} comes only with System III, System V, and later @acronym{BSD}
(4.3-tahoe and later).
@command{tar}'s way of handling multiple hard links to a file can handle
-file systems that support 32-bit inumbers (e.g., the BSD file system);
-@command{cpio}s way requires you to play some games (in its "binary"
-format, i-numbers are only 16 bits, and in its "portable ASCII" format,
-they're 18 bits---it would have to play games with the "file system ID"
-field of the header to make sure that the file system ID/i-number pairs
+file systems that support 32-bit inumbers (e.g., the @acronym{BSD} file system);
+@command{cpio}s way requires you to play some games (in its ``binary''
+format, i-numbers are only 16 bits, and in its ``portable @acronym{ASCII}'' format,
+they're 18 bits---it would have to play games with the "file system @acronym{ID}"
+field of the header to make sure that the file system @acronym{ID}/i-number pairs
of different files were always different), and I don't know which
@command{cpio}s, if any, play those games. Those that don't might get
confused and think two files are the same file when they're not, and
This means that the @option{--append}, @option{--concatenate}, and
@option{--delete} commands will not work on any other kind of file.
Some media simply cannot be backspaced, which means these commands and
-options will never be able to work on them. These non-backspacing
+options will never be able to work on them. These non-backspacing
media include pipes and cartridge tape drives.
Some other media can be backspaced, and @command{tar} will work on them
@xopindex{read-full-records, short description}
@item -B
@itemx --read-full-records
-Reblock as we read (for reading 4.2BSD pipes).
+Reblock as we read (for reading 4.2@acronym{BSD} pipes).
If @option{--read-full-records} is used, @command{tar}
will not panic if an attempt to read a record from the archive does
-not return a full record. Instead, @command{tar} will keep reading
+not return a full record. Instead, @command{tar} will keep reading
until it has obtained a full
record.
This option is turned on by default when @command{tar} is reading
an archive from standard input, or from a remote machine. This is
-because on BSD Unix systems, a read of a pipe will return however
+because on @acronym{BSD} Unix systems, a read of a pipe will return however
much happens to be in the pipe, even if it is less than @command{tar}
requested. If this option was not used, @command{tar} would fail as
soon as it read an incomplete record from the pipe.
projects / chaz / tar / commitdiff
