01/04: doc: Suggest how to preserve /var and /root owner and permissions.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit 8c3a5d7059a24e9c6d7bf14be296169cdcf06ad6
Author: Ludovic Courtès <address@hidden>
Date:   Sun May 17 22:53:11 2015 +0200

    doc: Suggest how to preserve /var and /root owner and permissions.
    
    Reported by Andreas Enge <address@hidden>.
    
    * doc/guix.texi (Binary Installation): Suggest --skip-old-files when
      extracting the archive.
---
 doc/guix.texi |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 049292d..7dd32c4 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -269,12 +269,18 @@ As @code{root}, run:
 
 @example
 # cd /
-# tar xf address@hidden@var{system}.tar.xz
+# tar --skip-old-files -xf \
+      address@hidden@var{system}.tar.xz
 @end example
 
 This creates @file{/gnu/store} (@pxref{The Store}), @file{/var/guix},
 and @file{/root/.guix-profile}.  @file{/root/.guix-profile} is a
 ready-to-use profile for @code{root} where Guix is installed.
address@hidden '--skip-old-files' does the right thing with tar 1.28.  The 
manual
address@hidden does not clearly document the behavior we describe here, though.
+The @code{--skip-old-files} option allows you to make sure the owner and
+permissions on @file{/var} and @file{/root} are preserved (@pxref{Option
+Summary, @code{--skip-old-files},, tar, GNU tar: an archiver tool}).
 
 Do @emph{not} unpack the tarball on a working Guix system since that
 would overwrite its own essential files.