Nicholas D Steeves posted on Wed, 25 May 2016 16:36:13 -0400 as excerpted:

On 25 May 2016 at 15:03, Duncan [off-list ref] wrote:

quoted

Dmitry Katsubo posted on Wed, 25 May 2016 16:45:41 +0200 as excerpted:

quoted

quoted

btrfs-restore [needs an o]ption that applies (y) to all questions
(completely unattended recovery)

That['s] a known sore spot that a lot of people have complained
about.

I'm surprised no one has mentioned, in any of these discussions, what I
believe is the standard method of providing this functionality:
yes | btrfs-restore -options /dev/disk

Good point.

I didn't bring it up because while I've used btrfs restore a few times, 
my btrfs are all on relatively small SSD partitions, so I both needed 
less y's, and the total time per restore is a few minutes, not hours, so 
it wasn't a big deal.  As a result, while I know of yes, I didn't need to 
think about automation, and as I never used it, it didn't occur to me to 
suggest it for others.

Had I needed to use it, however, I expect I would have reached for yes, 
myself, so good point indeed, pointing out its use to others.  I just 
wish I'd thought of mentioning it, now.  =:^)

And if you need it in your initrd on a Debian-like system, put the
following in /etc/initramfs-tools/hooks/yes.hook :

#!/bin/sh

. /usr/share/initramfs-tools/hook-functions

if command -v /usr/bin/yes >/dev/null 2>&1; then
    copy_exec /usr/bin/yes usr/bin/yes copy_exec /usr/bin/yes
    usr/bin/yes
fi

I haven't tested this, but it seems like it would do the trick.

FWIW, for those using a dracut-based initr* (which should be fedora/rh-
based distros as well as those like arch and gentoo, where it'd be an 
option, the recommended option in at least gentoo's case), it's a simple 
config file edit, with dracut taking care of the rest, including pulling 
in libraries for non-static binaries.  I've not used it for yes, but I've 
used it for a few other binaries.

I use the /etc/dracut.conf.d/* style of config here, and here's what I 
have in my specific installitems.conf file in that dir:

install_items+="
	/bin/most
	/bin/nano
"

(I don't have less, which dracut uses by default, on my system, 
preferring most.  And nano is a tiny but useful text editor that doesn't 
require the esoteric pre-use knowledge of something like vi/vim-minimal, 
tho I prefer the larger mc/mcedit in a less size constrained environment.)

Obviously I'd just need to include one more line there to pull in 
/bin/yes, if I wanted/needed it.  (Tho I've not checked, for all I know 
dracut pulls it in on its own or via some other module I'm already using.)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman