(extracting untrusted archives): New section.

[chaz/tar] / doc / tar.texi

diff --git a/doc/tar.texi b/doc/tar.texi
index 726661a9e5a143bb4cf947f683be883f17737c7d..6a91f7642dd995ff731e6b9d14e7aec79d0ea879 100644 (file)
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -145,6 +145,8 @@
 @set xref-checkpoint @xref{verbose}
 @set pxref-checkpoint @pxref{verbose}
 
+@set op-check-links @kbd{--check-links}
+
 @set op-compare @kbd{--compare} (@kbd{--diff}, @kbd{-d})
 @set ref-compare @ref{compare}
 @set xref-compare @xref{compare}
@@ -1800,6 +1802,7 @@ long form of the operation without affecting the performance.
 * extracting archives::
 * extracting files::
 * extract dir::
+* extracting untrusted archives::
 * failing commands::
 @end menu
 
@@ -1920,6 +1923,23 @@ of the file names when you extract those files from the archive.
 @FIXME{IMPORTANT!  show the final structure, here.  figure out what it
 will be.}
 
+@node extracting untrusted archives
+@subsection Extracting Archives from Untrusted Sources
+
+Extracting files from archives can overwrite files that already exist.
+If you receive an archive from an untrusted source, you should make a
+new directory and extract into that directory, so that you don't have
+to worry about the extraction overwriting one of your existing files.
+For example, if @file{untrusted.tar} came from somewhere else on the
+Internet, and you don't necessarily trust its contents, you can
+extract it as follows:
+
+@example
+$ @kbd{mkdir newdir}
+$ @kbd{cd newdir}
+$ @kbd{tar -xvf ../untrusted.tar}
+@end example
+
 @node failing commands
 @subsection Commands That Will Fail
 
@@ -2566,6 +2586,13 @@ reads through the archive.  Its intended for when you want a visual
 indication that @command{tar} is still running, but don't want to see
 @samp{--verbose} output.  @FIXME-xref{}
 
+@item --check-links
+
+If this option was given, @command{tar} will check the number of links
+dumped for each processed file. If this number does not match the
+total number of hard links for the file, a warning message will be
+output.
+
 @item --compress
 @itemx --uncompress
 @itemx -Z
@@ -7766,11 +7793,7 @@ device,
 invocation.
 @end itemize
 
-In previous versions of @acronym{GNU} @command{tar}, the
-@samp{--compress-block} option (or even older:
-@samp{--block-compress}) was necessary to reblock compressed archives.
-It is now a dummy option just asking not to be used, and otherwise
-ignored.  If the output goes directly to a local disk, and not through
+If the output goes directly to a local disk, and not through
 stdout, then the last write is not extended to a full record size.
 Otherwise, reblocking occurs.  Here are a few other remarks on this
 topic: