From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Noah Lavine Newsgroups: gmane.emacs.tramp,gmane.emacs.devel Subject: Re: SCPC Detection Program Date: Mon, 12 Apr 2010 15:06:56 -0400 Message-ID: References: <8739z26jxo.fsf@gmx.de> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1271103892 6488 80.91.229.12 (12 Apr 2010 20:24:52 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 12 Apr 2010 20:24:52 +0000 (UTC) Cc: tramp-devel@gnu.org, emacs-devel@gnu.org To: Michael Albinus Original-X-From: tramp-devel-bounces+tramp=quimby.gnus.org@gnu.org Mon Apr 12 22:24:50 2010 Return-path: Envelope-to: tramp@deer.gmane.org Original-Received: from quimby.gnus.org ([80.91.231.51]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1O1QBa-0003Bm-92 for tramp@deer.gmane.org; Mon, 12 Apr 2010 22:24:46 +0200 Original-Received: from lists.gnu.org ([199.232.76.165]) by quimby.gnus.org with esmtp (Exim 3.36 #1 (Debian)) id 1O1QBZ-00033u-00 for ; Mon, 12 Apr 2010 22:24:46 +0200 Original-Received: from localhost ([127.0.0.1]:60301 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1O1QBY-0002JU-H4 for tramp@quimby.gnus.org; Mon, 12 Apr 2010 16:24:44 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1O1OyR-0003DC-PQ for tramp-devel@gnu.org; Mon, 12 Apr 2010 15:07:07 -0400 Original-Received: from [140.186.70.92] (port=52407 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1O1OyP-0003CP-OQ for tramp-devel@gnu.org; Mon, 12 Apr 2010 15:07:06 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1O1OyO-0007Pa-FU for tramp-devel@gnu.org; Mon, 12 Apr 2010 15:07:05 -0400 Original-Received: from mail-pz0-f198.google.com ([209.85.222.198]:55669) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1O1OyI-0007OS-W1; Mon, 12 Apr 2010 15:06:59 -0400 Original-Received: by pzk36 with SMTP id 36so4644940pzk.24 for ; Mon, 12 Apr 2010 12:06:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:received:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=xKsRqbMMalku09wcq8Souu8jxCYZEIaH7UOhobNinkw=; b=xAZbAujgs6yeKzEv1Zu1N6rr8qrpZd8CYDJHyQkH/HMNdDTgl5i7N6WRS+cYoil2Ok TjJ3BhNmYDbIL86M8JArbkD64CyOpzQbFBOWqn/wW7Rtmr0VvvIkoxsfEWkkT+oSvKAB TI6XH0pmUjxWIsiqC6d2BghjgtbRimp4JZllQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=pw6y7hn5r00w6nIGWCdryilGSu6bdN3R4jFGwZH4z0YcPI5MJpCRukSOBEmB/s7M0c vMjZIbqIte886xZpPKVWaajQmye7/4Ay94sBKUBmEesl3oCb4yRSUbZwNgj31RGMB+KV Drw8Kivrg9WopHcATNv7bLiNPgZMYTnuc/fYo= Original-Received: by 10.231.37.2 with HTTP; Mon, 12 Apr 2010 12:06:56 -0700 (PDT) In-Reply-To: <8739z26jxo.fsf@gmx.de> Original-Received: by 10.114.188.30 with SMTP id l30mr4009800waf.134.1271099216802; Mon, 12 Apr 2010 12:06:56 -0700 (PDT) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Mailman-Approved-At: Mon, 12 Apr 2010 16:24:40 -0400 X-BeenThere: tramp-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: tramp-devel.gnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: tramp-devel-bounces+tramp=quimby.gnus.org@gnu.org Errors-To: tramp-devel-bounces+tramp=quimby.gnus.org@gnu.org Xref: news.gmane.org gmane.emacs.tramp:7229 gmane.emacs.devel:123541 Archived-At: Michael, I see your point about version numbers, but I don't think it's as good to add a hint to the Tramp manual, because users still have to look through it to see that it's there and then configure Tramp. In general, I think it's safe to assume that they will read the manual as little as possible in order to accomplish whatever task they're trying to accomplish. For instance, I used Tramp for a while before I realized that there was a way to make it stop asking for my password all the time. This is basically my effort to make sure that this doesn't happen to other users in the future. Is there a commonly-used way to discover the capabilities of a system other than version numbers? Talking to the system package manager would also work for most (although not all) cases, and I could look into writing a connection to PackageKit if that seemed like it could work. It would also be really cool if the ssh program had a way to tell us what command-line arguments it accepted, but I don't see any way to do that short of asking it to open up a test connection and seeing if it gave an error message. That might actually be a reasonable way to do this, if you defer the checking until the first use of ssh - first try opening a connection with ControlMaster, and if that fails, try again without it. Noah On Sun, Apr 11, 2010 at 12:19 PM, Michael Albinus wrote: > Noah Lavine writes: > >> Dear Tramp Developers, > > Hi, > >> I recently started using Tramp and learned about the different access >> methods. As I understand it, the `scpc` method is superior to the >> `ssh` method, but can't be set as default because of old versions of >> ssh that don't support the ControlMaster argument. >> >> It seems to me that it would be better if Tramp could automatically >> detect whether the version of ssh on a computer supported the >> ControlMaster argument and use scpc if it were possible. Therefore, I >> started working on a program to detect this based on the SSH version >> string. The following program correctly detects the presence of an SSH >> version greater than 4.0 on my computer: > > I am not too happy in detecting features by checking version numbers of > programs. This will work for a while, and this will generate problems > later on, likely. > > Maybe it is sufficient to add a hint to the Tramp manual, that the > following setting in the ssh config file is useful, when applicable by > the underlying ssh version: > > Host * > =A0 =A0 =A0 =A0ControlMaster auto > =A0 =A0 =A0 =A0ControlPath =A0 /tmp/%r@%h:%p > >> Noah Lavine > > Best regards, Michael. >