X-Git-Url: https://git.dogcows.com/gitweb?a=blobdiff_plain;f=doc%2Ftar.texi;h=fe09c1275df27554bbf012ddc63046ea5097774f;hb=67cad07;hp=f86f077ad9e7811da802419c3ec771b60cabfa09;hpb=c78356fedadbe36aae1e063c69d11636c86d35e6;p=chaz%2Ftar diff --git a/doc/tar.texi b/doc/tar.texi index f86f077..fe09c12 100644 --- a/doc/tar.texi +++ b/doc/tar.texi @@ -35,7 +35,7 @@ This manual is for @acronym{GNU} @command{tar} (version from archives. Copyright @copyright{} 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001, -2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. +2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. @quotation Permission is granted to copy, distribute and/or modify this document @@ -1429,12 +1429,12 @@ example: @smallexample @group -$ @kbd{tar cfv archive /etc/mail} +$ @kbd{tar --create --verbose --file archive /etc/mail} tar: Removing leading `/' from member names /etc/mail/ /etc/mail/sendmail.cf /etc/mail/aliases -$ @kbd{tar tf archive} +$ @kbd{tar --test --file archive} etc/mail/ etc/mail/sendmail.cf etc/mail/aliases @@ -1879,15 +1879,14 @@ will act on the entire contents of the archive. @cindex return status Besides successful exits, @GNUTAR{} may fail for many reasons. Some reasons correspond to bad usage, that is, when the -@command{tar} command is improperly written. Errors may be -encountered later, while encountering an error processing the archive -or the files. Some errors are recoverable, in which case the failure -is delayed until @command{tar} has completed all its work. Some -errors are such that it would not meaningful, or at least risky, to -continue processing: @command{tar} then aborts processing immediately. -All abnormal exits, whether immediate or delayed, should always be -clearly diagnosed on @code{stderr}, after a line stating the nature of -the error. +@command{tar} command line is improperly written. Errors may be +encountered later, while processing the archive or the files. Some +errors are recoverable, in which case the failure is delayed until +@command{tar} has completed all its work. Some errors are such that +it would be not meaningful, or at least risky, to continue processing: +@command{tar} then aborts processing immediately. All abnormal exits, +whether immediate or delayed, should always be clearly diagnosed on +@code{stderr}, after a line stating the nature of the error. Possible exit codes of @GNUTAR{} are summarized in the following table: @@ -1924,7 +1923,7 @@ remote device (@pxref{Remote Tape Server}). allow you to perform a variety of tasks. You are required to choose one operating mode each time you employ the @command{tar} program by specifying one, and only one operation as an argument to the -@command{tar} command (two lists of four operations each may be found +@command{tar} command (the corresponding options may be found at @ref{frequent operations} and @ref{Operations}). Depending on circumstances, you may also wish to customize how the chosen operating mode behaves. For example, you may wish to change the way the output @@ -2786,7 +2785,6 @@ incremental format. @xref{Incremental Dumps}. @opsummary{lzma} @item --lzma -@itemx -J This option tells @command{tar} to read or write archives through @command{lzma}. @xref{gzip}. @@ -3266,8 +3264,9 @@ rather than the data modification time stored in the archive. @xref{Data Modification Times}. @opsummary{transform} +@opsummary{xform} @item --transform=@var{sed-expr} - +@itemx --xform=@var{sed-expr} Transform file or member names using @command{sed} replacement expression @var{sed-expr}. For example, @@ -3308,6 +3307,7 @@ name quoting}. @opsummary{use-compress-program} @item --use-compress-program=@var{prog} +@itemx -I=@var{prog} Instructs @command{tar} to access the archive through @var{prog}, which is presumed to be a compression program of some sort. @xref{gzip}. @@ -3357,6 +3357,12 @@ Use wildcards when matching member names with patterns. @item --wildcards-match-slash Wildcards match @samp{/}. @xref{controlling pattern-matching}. + +@opsummary{xz} +@item --xz +@itemx -J +Use @command{xz} for compressing or decompressing the archives. @xref{gzip}. + @end table @node Short Option Summary @@ -3378,7 +3384,7 @@ them with the equivalent long option. @item -G @tab @ref{--incremental}. -@item -J @tab @ref{--lzma}. +@item -J @tab @ref{--xz}. @item -K @tab @ref{--starting-file}. @@ -3740,7 +3746,7 @@ If @option{--block-number} (@option{-R}) is used, @command{tar} prints, along wi every message it would normally produce, the block number within the archive where the message was triggered. Also, supplementary messages are triggered when reading blocks full of NULs, or when hitting end of -file on the archive. As of now, if the archive if properly terminated +file on the archive. As of now, if the archive is properly terminated with a NUL block, the reading of the file may stop before end of file is met, so the position of end of file will not usually show when @option{--block-number} (@option{-R}) is used. Note that @GNUTAR{} @@ -4137,7 +4143,7 @@ The five operations that we will cover in this chapter are: @itemx -r Add new entries to an archive that already exists. @item --update -@itemx -r +@itemx -u Add more recent copies of archive members to the end of an archive, if they exist. @item --concatenate @@ -5345,9 +5351,9 @@ and @command{mv}, for example) offer similar options. Backup options may prove unexpectedly useful when extracting archives containing many members having identical name, or when extracting archives on systems having file name limitations, making different members appear -has having similar names through the side-effect of name truncation. -(This is true only if we have a good scheme for truncated backup names, -which I'm not sure at all: I suspect work is needed in this area.) +as having similar names through the side-effect of name truncation. +@FIXME{This is true only if we have a good scheme for truncated backup names, +which I'm not sure at all: I suspect work is needed in this area.} When any existing file is backed up before being overwritten by extraction, then clashing files are automatically be renamed to be unique, and the true name is kept for only the last file of a series of clashing files. @@ -7553,7 +7559,7 @@ characters that are quoted by default in the selected quoting style. @command{Tar} archives contain detailed information about files stored in them and full file names are part of that information. When -storing file to an archive, its file name is recorded in the archive +storing file to an archive, its file name is recorded in it, along with the actual file contents. When restoring from an archive, a file is created on disk with exactly the same name as that stored in the archive. In the majority of cases this is the desired behavior @@ -7570,7 +7576,7 @@ directory components, or with otherwise modified names. In other cases it is desirable to store files under differing names in the archive. -@GNUTAR{} provides two options for these needs. +@GNUTAR{} provides several options for these needs. @table @option @opindex strip-components @@ -7592,8 +7598,8 @@ The option @option{--strip=2} instructs @command{tar} to strip the two leading components (@file{usr/} and @file{include/}) off the file name. -If you add to the above invocation @option{--verbose} (@option{-v}) -option, you will note that the verbose listing still contains the +If you add the @option{--verbose} (@option{-v}) option to the invocation +above, you will note that the verbose listing still contains the full file name, with the two removed components still in place. This can be inconvenient, so @command{tar} provides a special option for altering this behavior: @@ -7618,7 +7624,7 @@ stdlib.h @end group @end smallexample -Notice that in both cases the file is @file{stdlib.h} extracted to the +Notice that in both cases the file @file{stdlib.h} is extracted to the current working directory, @option{--show-transformed-names} affects only the way its name is displayed. @@ -7644,7 +7650,9 @@ In case you need to apply more complex modifications to the file name, @table @option @opindex transform +@opindex xform @item --transform=@var{expression} +@itemx --xform=@var{expression} Modify file names using supplied @var{expression}. @end table @@ -7662,6 +7670,21 @@ replacement for each file name part that matches @var{regexp}. Both @var{regexp} and @var{replace} are described in detail in @ref{The "s" Command, The "s" Command, The `s' Command, sed, GNU sed}. +Any delimiter can be used in lieue of @samp{/}, the only requirement being +that it be used consistently throughout the expression. For example, +the following two expressions are equivalent: + +@smallexample +@group +s/one/two/ +s,one,two, +@end group +@end smallexample + +Changing delimiters is often useful when the @var{regex} contains +slashes. For example, it is more convenient to write @code{s,/,-,} than +@code{s/\//-/}. + As in @command{sed}, you can give several replace expressions, separated by a semicolon. @@ -7683,7 +7706,7 @@ sed, GNU sed}). @item @var{number} Only replace the @var{number}th match of the @var{regexp}. -Note: the @var{posix} standard does not specify what should happen +Note: the @acronym{POSIX} standard does not specify what should happen when you mix the @samp{g} and @var{number} modifiers. @GNUTAR{} follows the GNU @command{sed} implementation in this regard, so the interaction is defined to be: ignore matches before the @@ -7692,21 +7715,41 @@ the interaction is defined to be: ignore matches before the @end table -Any delimiter can be used in lieue of @samp{/}, the only requirement being -that it be used consistently throughout the expression. For example, -the following two expressions are equivalent: +In addition, several @dfn{transformation scope} flags are supported, +that control to what files transformations apply. These are: + +@table @samp +@item r +Apply transformation to regular archive members. + +@item R +Do not apply transformation to regular archive members. + +@item s +Apply transformation to symbolic link targets. + +@item S +Do not apply transformation to symbolic link targets. + +@item h +Apply transformation to hard link targets. + +@item H +Do not apply transformation to hard link targets. +@end table + +Default is @samp{rsh}, which means to apply tranformations to both archive +members and targets of symbolic and hard links. + +Default scope flags can also be changed using @samp{flags=} statement +in the transform expression. The flags set this way remain in force +until next @samp{flags=} statement or end of expression, whichever +occurs first. For example: @smallexample -@group -s/one/two/ -s,one,two, -@end group + --transform 'flags=S;s|^|/usr/local/|' @end smallexample -Changing delimiters is often useful when the @var{regex} contains -slashes. For example, it is more convenient to write @code{s,/,-,} than -@code{s/\//-/}. - Here are several examples of @option{--transform} usage: @enumerate @@ -7723,20 +7766,59 @@ $ @kbd{tar --transform='s,usr/,usr/local/,' -x -f arch.tar} $ @kbd{tar --transform='s,/*[^/]*/[^/]*/,,' -x -f arch.tar} @end smallexample +@item Convert each file name to lower case: + +@smallexample +$ @kbd{tar --transform 's/.*/\L&/' -x -f arch.tar} +@end smallexample + @item Prepend @file{/prefix/} to each file name: @smallexample $ @kbd{tar --transform 's,^,/prefix/,' -x -f arch.tar} @end smallexample -@item Convert each file name to lower case: +@item Archive the @file{/lib} directory, prepending @samp{/usr/local} +to each archive member: @smallexample -$ @kbd{tar --transform 's/.*/\L&/' -x -f arch.tar} +$ @kbd{tar --transform 's,^,/usr/local/,S' -c -f arch.tar /lib} @end smallexample - @end enumerate +Notice the use of flags in the last example. The @file{/lib} +directory often contains many symbolic links to files within it. +It may look, for example, like this: + +@smallexample +$ @kbd{ls -l} +drwxr-xr-x root/root 0 2008-07-08 16:20 /lib/ +-rwxr-xr-x root/root 1250840 2008-05-25 07:44 /lib/libc-2.3.2.so +lrwxrwxrwx root/root 0 2008-06-24 17:12 /lib/libc.so.6 -> libc-2.3.2.so +... +@end smallexample + +Using the expression @samp{s,^,/usr/local/,} would mean adding +@samp{/usr/local} to both regular archive members and to link +targets. In this case, @file{/lib/libc.so.6} would become: + +@smallexample + /usr/local/lib/libc.so.6 -> /usr/local/libc-2.3.2.so +@end smallexample + +This is definitely not desired. To avoid this, the @samp{S} flag +are used, which excludes symbolic link targets from filename +transformations. The result is: + +@smallexample +$ @kbd{tar --transform 's,^,/usr/local/,S', -c -v -f arch.tar \ + --show-transformed /lib} +drwxr-xr-x root/root 0 2008-07-08 16:20 /usr/local/lib/ +-rwxr-xr-x root/root 1250840 2008-05-25 07:44 /usr/local/lib/libc-2.3.2.so +lrwxrwxrwx root/root 0 2008-06-24 17:12 /usr/local/lib/libc.so.6 -> +libc-2.3.2.so +@end smallexample + Unlike @option{--strip-components}, @option{--transform} can be used in any @GNUTAR{} operation mode. For example, the following command adds files to the archive while replacing the leading @file{usr/} @@ -8328,7 +8410,8 @@ Creating a compressed archive is simple: you just specify a commands. The compression option is @option{-z} (@option{--gzip}) to create a @command{gzip} compressed archive, @option{-j} (@option{--bzip2}) to create a @command{bzip2} compressed archive, -@option{-J} (@option{--lzma}) to create an @asis{LZMA} compressed +@option{-J} (@option{--xz}) to create an @asis{XZ} archive, +@option{--lzma} to create an @asis{LZMA} compressed archive, @option{--lzop} to create an @asis{LSOP} archive, and @option{-Z} (@option{--compress}) to use @command{compress} program. For example: @@ -8426,6 +8509,7 @@ suffix. The following suffixes are recognized: @item @samp{.lzma} @tab @command{lzma} @item @samp{.tlz} @tab @command{lzma} @item @samp{.lzo} @tab @command{lzop} +@item @samp{.xz} @tab @command{xz} @end multitable @opindex gzip @@ -8470,13 +8554,17 @@ lose some compressibility. But this would have make recovering easier. So, there are pros and cons. We'll see! @opindex bzip2 +@item -J +@itemx --xz +Filter the archive through @code{xz}. Otherwise like +@option{--gzip}. + @item -j @itemx --bzip2 Filter the archive through @code{bzip2}. Otherwise like @option{--gzip}. @opindex lzma @item --lzma -@itemx -J Filter the archive through @command{lzma}. Otherwise like @option{--gzip}. @opindex lzop @@ -8493,6 +8581,7 @@ Filter the archive through @command{compress}. Otherwise like @option{--gzip}. @opindex use-compress-program @item --use-compress-program=@var{prog} +@itemx -I=@var{prog} Use external compression program @var{prog}. Use this option if you have a compression program that @GNUTAR{} does not support. There are two requirements to which @var{prog} should comply: @@ -8531,14 +8620,14 @@ Suppose you name it @file{gpgz} and save it somewhere in your archive signed with your private key: @smallexample -$ @kbd{tar -cf foo.tar.gpgz --use-compress=gpgz .} +$ @kbd{tar -cf foo.tar.gpgz -Igpgz .} @end smallexample @noindent -Likewise, the following command will list its contents: +Likewise, the command below will list its contents: @smallexample -$ @kbd{tar -tf foo.tar.gpgz --use-compress=gpgz .} +$ @kbd{tar -tf foo.tar.gpgz -Igpgz .} @end smallexample @ignore @@ -8810,11 +8899,7 @@ This option is meaningless with @option{--list} (@option{-t}). @item --preserve Same as both @option{--same-permissions} and @option{--same-order}. -The @option{--preserve} option has no equivalent short option name. -It is equivalent to @option{--same-permissions} plus @option{--same-order}. - -@FIXME{I do not see the purpose of such an option. (Neither I. FP.) -Neither do I. --Sergey} +This option is deprecated, and will be removed in @GNUTAR{} version 1.23. @end table @@ -9200,7 +9285,7 @@ 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 reading, @GNUTAR{} computes both checksums and -accept any. It is somewhat worrying that a lot of people may go +accepts any. It is somewhat worrying that a lot of people may go around doing backup of their files using faulty (or at least non-standard) software, not learning about it until it's time to restore their missing files with an incompatible file extractor, or