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authorPaul Eggert <eggert@cs.ucla.edu>2011-05-26 12:09:52 -0700
committerPaul Eggert <eggert@cs.ucla.edu>2011-05-26 12:10:39 -0700
commit9708b248e8e0139e43be400086e9dfd7b145aeda (patch)
treef6c28bce3fa46fe3ec4b6b471cffbca2a8aecf0e
parentafcdb894920d2a2ba34a6a1fcf6f57d6490a804f (diff)
downloadtar-9708b248e8e0139e43be400086e9dfd7b145aeda.tar.gz
* doc/tar.texi (Old Options): Clarify distinction from short options.
Adjust other parts of the manual to use examples that parse the same regardless of whether "-" is in front of the option clump. See <http://lists.gnu.org/archive/html/bug-tar/2011-05/msg00022.html>.
-rw-r--r--doc/tar.texi50
1 files changed, 23 insertions, 27 deletions
diff --git a/doc/tar.texi b/doc/tar.texi
index db8f986e..357c8c1c 100644
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -2117,12 +2117,20 @@ end up overwriting files.
@subsection Old Option Style
@cindex options, old style
@cindex old option style
+@cindex option syntax, traditional
-Like short options, @dfn{old options} are single letters. However, old options
+As far as we know, all @command{tar} programs, @acronym{GNU} and
+non-@acronym{GNU}, support @dfn{old options}: that is, if the first
+argument does not start with @samp{-}, it is assumed to specify option
+letters. @GNUTAR{} supports old options not only for historical
+reasons, but also because many people are used to them. If the first
+argument does not start with a dash, you are announcing the old option
+style instead of the short option style; old options are decoded
+differently.
+
+Like short options, old options are single letters. However, old options
must be written together as a single clumped set, without spaces separating
-them or dashes preceding them@footnote{Beware that if you precede options
-with a dash, you are announcing the short option style instead of the
-old option style; short options are decoded differently.}. This set
+them or dashes preceding them. This set
of letters must be the first to appear on the command line, after the
@command{tar} program name and some white space; old options cannot appear
anywhere else. The letter of an old option is exactly the same letter as
@@ -2146,7 +2154,7 @@ $ @kbd{tar cvbf 20 /dev/rmt0}
Here, @samp{20} is the argument of @option{-b} and @samp{/dev/rmt0} is
the argument of @option{-f}.
-On the other hand, this old style syntax makes it difficult to match
+The old style syntax can make it difficult to match
option letters with their corresponding arguments, and is often
confusing. In the command @w{@samp{tar cvbf 20 /dev/rmt0}}, for example,
@samp{20} is the argument for @option{-b}, @samp{/dev/rmt0} is the
@@ -2172,8 +2180,6 @@ the value for option @samp{f} and recognizes the option @samp{z}. The
second example, however, uses @file{z} as the value for option
@samp{f} --- probably not what was intended.
-Old options are kept for compatibility with old versions of @command{tar}.
-
This second example could be corrected in many ways, among which the
following are equivalent:
@@ -2183,16 +2189,6 @@ following are equivalent:
@kbd{tar cf archive.tar.gz -z file}
@end smallexample
-@cindex option syntax, traditional
-As far as we know, all @command{tar} programs, @acronym{GNU} and
-non-@acronym{GNU}, support old options. @GNUTAR{}
-supports them not only for historical reasons, but also because many
-people are used to them. For compatibility with Unix @command{tar},
-the first argument is always treated as containing command and option
-letters even if it doesn't start with @samp{-}. Thus, @samp{tar c} is
-equivalent to @w{@samp{tar -c}:} both of them specify the
-@option{--create} (@option{-c}) command to create an archive.
-
@node Mixing
@subsection Mixing Option Styles
@@ -3732,7 +3728,7 @@ $ @kbd{tar xvvf archive.tar}
Verbose output appears on the standard output except when an archive is
being written to the standard output, as with @samp{tar --create
---file=- --verbose} (@samp{tar cfv -}, or even @samp{tar cv}---if the
+--file=- --verbose} (@samp{tar cvf -}, or even @samp{tar cv}---if the
installer let standard output be the default archive). In that case
@command{tar} writes verbose output to the standard error stream.
@@ -4312,7 +4308,7 @@ the following commands:
@smallexample
@kbd{tar --create --file=empty-archive.tar --files-from=/dev/null}
-@kbd{tar cfT empty-archive.tar /dev/null}
+@kbd{tar -cf empty-archive.tar -T /dev/null}
@end smallexample
@xopindex{extract, complementary notes}
@@ -8730,7 +8726,7 @@ archive, @option{--lzop} to create an @asis{LSOP} archive, and
For example:
@smallexample
-$ @kbd{tar cfz archive.tar.gz .}
+$ @kbd{tar czf archive.tar.gz .}
@end smallexample
You can also let @GNUTAR{} select the compression program based on
@@ -8740,14 +8736,14 @@ example, the following invocation will use @command{bzip2} for
compression:
@smallexample
-$ @kbd{tar cfa archive.tar.bz2 .}
+$ @kbd{tar caf archive.tar.bz2 .}
@end smallexample
@noindent
whereas the following one will use @command{lzma}:
@smallexample
-$ @kbd{tar cfa archive.tar.lzma .}
+$ @kbd{tar caf archive.tar.lzma .}
@end smallexample
For a complete list of file name suffixes recognized by @GNUTAR{},
@@ -8804,7 +8800,7 @@ If you see such diagnostics, just add the suggested option to the
invocation of @GNUTAR{}:
@smallexample
-$ @kbd{cat archive.tar.gz | tar tfz -}
+$ @kbd{cat archive.tar.gz | tar tzf -}
@end smallexample
Notice also, that there are several restrictions on operations on
@@ -8875,7 +8871,7 @@ environment variable. For example, when using @command{gzip} you can
use @env{GZIP} as in the example below:
@smallexample
-$ @kbd{GZIP=--best tar cfz archive.tar.gz subdir}
+$ @kbd{GZIP=--best tar czf archive.tar.gz subdir}
@end smallexample
@noindent
@@ -9397,7 +9393,7 @@ directory with a verbose level 2, you will get an output similar to
the following:
@smallexample
-$ tar cfvv ../archive.tar .
+$ tar cvvf ../archive.tar .
drwxr-xr-x gray/staff 0 2007-10-30 15:13 ./
-rw-r--r-- gray/staff 4 2007-10-30 15:11 ./jeden
hrw-r--r-- gray/staff 0 2007-10-30 15:11 ./one link to ./jeden
@@ -11367,7 +11363,7 @@ second tape, and then back to the first tape, etc., just do either of:
@smallexample
$ @kbd{tar --create --multi-volume --file=/dev/tape0 --file=/dev/tape1 @var{files}}
-$ @kbd{tar cMff /dev/tape0 /dev/tape1 @var{files}}
+$ @kbd{tar -cM -f /dev/tape0 -f /dev/tape1 @var{files}}
@end smallexample
The second method is to use the @samp{n} response to the tape-change
@@ -11646,7 +11642,7 @@ manage to get some date string as part of the label. For example:
@smallexample
@group
-$ @kbd{tar cfMV /dev/tape "Daily backup for `date +%Y-%m-%d`"}
+$ @kbd{tar -cM -f /dev/tape -V "Daily backup for `date +%Y-%m-%d`"}
$ @kbd{tar --create --file=/dev/tape --multi-volume \
--label="Daily backup for `date +%Y-%m-%d`"}
@end group