Fix description of the CACHEDIR.TAG file.

[thirdparty/tar.git] / doc / tar.texi

diff --git a/doc/tar.texi b/doc/tar.texi
index 6994a5bd7dc861d6bc7672c76c93d93f84caf089..ddbf8cba01b75c4c5f3e0f9f54d668d98b00f540 100644 (file)
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -8218,9 +8218,19 @@ that match the following shell globbing patterns:
 @findex exclude-caches
 When creating an archive, the @option{--exclude-caches} option family
 causes @command{tar} to exclude all directories that contain a @dfn{cache
-directory tag}. A cache directory tag is a short file with the
-well-known name @file{CACHEDIR.TAG} and having a standard header
-specified in @url{http://www.brynosaurus.com/cachedir/spec.html}.
+directory tag}. A cache directory tag is a regular file with the
+well-known name @file{CACHEDIR.TAG} whose first 43 octets
+consist of the following ASCII header string:
+
+@example
+Signature: 8a477f597d28d172789f06886806bc55
+@end example
+
+Any remaining bytes are not relevant, in particular the signature
+string does not have to be followed by an LF or CR/LF pair@footnote{The
+cache directory tagging specification is set forth in
+@url{https://bford.info/cachedir/}}.
+
 Various applications write cache directory tags into directories they
 use to hold regenerable, non-precious data, so that such data can be
 more easily excluded from backups.