From owner-svn-src-head@FreeBSD.ORG Mon May 11 19:37:32 2015 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3F6EC1F2; Mon, 11 May 2015 19:37:32 +0000 (UTC) Received: from shxd.cx (mail.shxd.cx [64.201.244.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 26F861F9F; Mon, 11 May 2015 19:37:32 +0000 (UTC) Received: from [64.201.244.132] (port=55656 helo=[10.0.0.102]) by shxd.cx with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.77 (FreeBSD)) (envelope-from ) id 1Yrsle-00073h-8n; Mon, 11 May 2015 11:49:30 -0700 Mime-Version: 1.0 (Mac OS X Mail 8.0 \(1990.1\)) Subject: Re: svn commit: r282672 - head/etc/rc.d From: Devin Teske In-Reply-To: <20150511191850.GC68045@spindle.one-eyed-alien.net> Date: Mon, 11 May 2015 12:37:29 -0700 Cc: John Baldwin , Xin LI , "src-committers@freebsd.org" , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" , Devin Teske Message-Id: <9FB76653-EF89-48E5-B4E8-A2006923B76A@FreeBSD.org> References: <201505082336.t48NaWRS080408@svn.freebsd.org> <20150511191850.GC68045@spindle.one-eyed-alien.net> To: Brooks Davis X-Mailer: Apple Mail (2.1990.1) Sender: devin@shxd.cx Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 May 2015 19:37:32 -0000 > On May 11, 2015, at 12:18 PM, Brooks Davis wrote: >=20 > On Sun, May 10, 2015 at 03:45:48PM -0400, John Baldwin wrote: >>=20 >>> On May 8, 2015, at 19:36, Xin LI wrote: >>>=20 >>> Author: delphij >>> Date: Fri May 8 23:36:31 2015 >>> New Revision: 282672 >>> URL: https://svnweb.freebsd.org/changeset/base/282672 >>>=20 >>> Log: >>> Always convert uuid to lower case. >>>=20 >>> MFC after: 2 weeks >>>=20 >>> Modified: >>> head/etc/rc.d/hostid >>>=20 >>> Modified: head/etc/rc.d/hostid >>> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D >>> --- head/etc/rc.d/hostid Fri May 8 23:29:42 2015 (r282671) >>> +++ head/etc/rc.d/hostid Fri May 8 23:36:31 2015 (r282672) >>> @@ -58,7 +58,7 @@ hostid_set() >>>=20 >>> valid_hostid() >>> { >>> - uuid=3D$1 >>> + uuid=3D$(echo $1 | tr '[:upper:]' '[:lower:]') >>=20 >> tr is in /usr/bin so this breaks systems with a separate /usr. = Perhaps you could use dd with conv=3Dlcase instead? >=20 > Alterntively, a shell function "ltr" exists in rc.subr for this = purpose. >=20 ltr would not work in this situation, for multiple reasons. 1. ltr doesn=E2=80=99t support character classes 2. ltr is for replacing one or more characters (cannot be a class) with = a single string (of variable length, 0+). In /etc/networks.subr you can see an example usage of ltr: 287 = = _punct=3D".-/+" 288 = = ltr ${_if} "${_punct}" '_' _if The result of this is to take a value of (for example) foo.bar and = replace any occurrences of period, minus, forward slash, or plus with instead a single underscore. The result is stuffed into the variable =E2=80=9C_if=E2= =80=9D (over- writing previous contents which may have contained aforementioned characters replaced with underscore). An attempt to use ltr in the below fashion: ltr $string =E2=80=98[:lower:]=E2=80=99 =E2=80=98[:upper:]=E2=80=99= somevar would surely fail. While it is indeed *possible* to write a find/replace function in = native- shell that supports character classes, it would not be a small function. The primary issue is that you need to know what the character that matched the class and there aren=E2=80=99t any built-ins that provide = this info. For example: case =E2=80=9C$src=E2=80=9D in *[[:lower:]]*) will trigger when you have a lower-case character that needs conversion to upper-case (or opposite if using *[[:upper:]]*) BUT you won=E2=80=99t = know what the character was that you matched (so how can you know which upper-case character to supplant)? The function will have to resort to complicated substring mechanics or any other seldom known procedure. I=E2=80=99ll have a noodle on it and see what I can come up with. It=E2=80= =99s not exactly immediately coming to me how to do this in any simple fashion while maintaining efficiency (read: by not iterating over every single = character and also by not having a giant massive case statement with every letter spelled out =E2=80=94 coming up with a solution that embraces the use of = the character class I would believe to be more efficient). =E2=80=94=20 Devin=