tar not reading if output directed to /dev/null Post: 302351501

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Operating Systems Linux Ubuntu tar not reading if output directed to /dev/null Post 302351501 by bakunin on Tuesday 8th of September 2009 06:57:21 PM

09-08-2009

Registered User

First off, I'd like to state that i do NOT have a problem. I just want to achieve a better understanding. So you don't need to tell me workarounds, as i have already found one.

Quote:

Originally Posted by thegeek

Before that why you would want to tar and check the integrity, better you can do by reading all the files !!

This is exactly what i was expecting tar to do: read all the files.

Quote:

Originally Posted by methyl

The parameter after "-f" is the archive filename. A value of "-" when there is no pipeline has no sensible meaning

Sorry, but this is simply not true: the dash as a filename is signifying <stdout> and if i use a redirection or a pipeline to manipulate tars output further should make no difference.

In fact (as i have stated in my first post) the command worked the way i wrote it when i used a real file (instead of /dev/null) as output destination. It is this inconsistency - the command reading all the files when a real file is the destination and not working, when the destination is /dev/null - i want to understand.

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LEARN ABOUT DEBIAN

virt-tar-out

virt-tar-out(1) 					      Virtualization Support						   virt-tar-out(1)

NAME

       virt-tar-out - Pack a virtual machine disk image directory into a tarball.

SYNOPSIS

	virt-tar-out -a disk.img /dir files.tar

	virt-tar-out -d domain /dir files.tar

	virt-tar-out -d domain /dir - | gzip --best > files.tar.gz

DESCRIPTION

       "virt-tar-out" packs a virtual machine disk image directory into a tarball.

       The first parameter is the absolute path of the virtual machine directory.  The second parameter is the tar file to write.  Use "-" to
       write to standard output.

EXAMPLES

       Download the home directories from a guest:

	virt-tar-out -d MyGuest /home - | gzip --best > homes.tar.gz

JUST A SHELL SCRIPT WRAPPER AROUND GUESTFISH

       This command is just a simple shell script wrapper around the guestfish(1) "tar-out" command.  For anything more complex than a trivial
       copy, you are probably better off using guestfish directly.

OPTIONS

       Since the shell script just passes options straight to guestfish, read guestfish(1) to see the full list of options.

SEE ALSO

       guestfish(1), virt-cat(1), virt-copy-in(1), virt-copy-out(1), virt-edit(1), virt-tar-in(1), <http://libguestfs.org/>.

AUTHORS

       Richard W.M. Jones ("rjones at redhat dot com")

COPYRIGHT

       Copyright (C) 2011 Red Hat Inc.	<http://libguestfs.org/>

       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
       the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation,
       Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

libguestfs-1.18.1						    2013-12-07							   virt-tar-out(1)

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