From: Axel Beckert <firstname.lastname@example.org>
Subject: Re: OpenSSH scp completion reminder
Date: Fri, 15 Apr 2022 14:46:32 +0200 [thread overview]
Message-ID: <email@example.com> (raw)
On Thu, Apr 14, 2022 at 04:44:33PM -0400, Phil Pennock wrote:
> On 2022-04-14 at 18:18 +0200, Axel Beckert wrote:
> > I thought so as well, but I so far couldn't find anything which didn't
> > work with zsh remote file completion with OpenSSH 9.0 on the client
> > side. Otherwise I would have reported it.
> What version was the server running?
I tried it with 8.4p1 (Debian 11 Bullseye) as well as with 9.0p1
(Debian Unstable) on the server side. And both times OpenSSH 9.0p1 and
Zsh 22.214.171.124-test on the client side.
> With localhost being 9.0 for client and server and zsh 5.8, I see this
> reproduction case; setup, then the results of tab-completion, and then
> at the end a manually-constructed filename which definitely would not
> have worked with older scp.
Oh, ok. Now I am confused, though.
> So the good news is that scp in the new mode is "pass the filename
> exactly as it really is, no escaping for the remote side, whatever
> reaches us in argv is what will be used, so you only need to worry
> about local shell escaping".
Correct. That's probably one of the things they wanted to get rid of.
> -O to use original SCP protocol, -s to use sftp protocol.
Thanks for that summary! I searched through the scp(1) man page several
times with different search terms for something like -s, but didn't
*lookingagain* Ah, they removed it again with the 9.0 release. No
traces of it in the 9.0p1 scp(1) man page. But it's in the one from
8.4p1. (I assumed that there is a way to revert a previously set -O —
maybe via config or so — on the commandline. But it seems as if
already the latter is not intended to be possible.)
> -D is for local debugging.
Huh? That's not in the scp(1) man page as of 8.4p1 and in the scp(1)
man page of 9.0p1, -D is documented as follows:
When using the SFTP protocol support via -M, connect
directly to a local SFTP server pro‐ gram rather than a
remote one via ssh(1). This option may be useful in
debugging the client and server.
Ah, I think you forgot to mention that "local debugging" meant "local
debugging on the server side" as sshd(8) mentions:
-D When this option is specified, sshd will not detach and
does not become a daemon. This allows easy monitoring of
> So I think full support means knowing the version, knowing which version
> switched the default behaviour (looks like 9.0 man-page might be
Yes, noticed that, too. It says, the SFTP backend is default since
8.8. But if you look at the upstream changelog, they made SFTP the
default multiple times and then reverted it and applied it again:
Date: Wed Feb 23 21:21:16 2022 +0000
upstream: put back the scp manpage changes for SFTP mode too
Date: Wed Feb 23 19:01:00 2022 +0000
upstream: and we go back to testing sftp-scp after the 8.9
Date: Thu Feb 10 04:12:38 2022 +0000
upstream: revert for imminent OpenSSH release, which wil ship with
scp in RCP mode.
> revision 1.106
> date: 2021/10/15 14:46:46; author: deraadt; state: Exp; lines: +13 -9; commitid: w5n9B2RE38tFfggl;
> openbsd 7.0 release shipped with the (hopefully last) scp that uses RCP
> protocol for copying. Let's get back to testing the SFTP protocol.
This will be put back once the OpenSSH release is done.
I assume that they didn't fix up the "Since OpenSSH 8.8, scp has use
the SFTP protocol for transfers by default" (sic!) phrase in the
scp(1) man page after reapplying the patches from after 8.7 again for
> and then knowing which options have been set on the command-line already
> for this version.
I also wondered if there's a possibility to configure the settings
relevant for rcp vs sftp as scp backend in ~/.ssh/config or
/etc/ssh/ssh_config. But I haven't found anything in that direction so
Kind regards, Axel
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prev parent reply other threads:[~2022-04-15 12:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 15:20 Phil Pennock
2022-04-14 16:18 ` Axel Beckert
2022-04-14 17:04 ` Bart Schaefer
2022-04-14 17:27 ` Axel Beckert
2022-04-14 17:34 ` Mikael Magnusson
2022-04-14 20:44 ` Phil Pennock
2022-04-15 12:46 ` Axel Beckert [this message]
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