From owner-freebsd-questions@FreeBSD.ORG Thu Dec 11 05:23:06 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 10BAF1065670; Thu, 11 Dec 2008 05:23:06 +0000 (UTC) (envelope-from mike@jellydonut.org) Received: from mail-fx0-f19.google.com (mail-fx0-f19.google.com [209.85.220.19]) by mx1.freebsd.org (Postfix) with ESMTP id E4C598FC1B; Thu, 11 Dec 2008 05:23:04 +0000 (UTC) (envelope-from mike@jellydonut.org) Received: by fxm12 with SMTP id 12so374573fxm.19 for ; Wed, 10 Dec 2008 21:23:03 -0800 (PST) Received: by 10.181.28.15 with SMTP id f15mr605520bkj.75.1228972983177; Wed, 10 Dec 2008 21:23:03 -0800 (PST) Received: by 10.181.240.8 with HTTP; Wed, 10 Dec 2008 21:23:03 -0800 (PST) Message-ID: <1de79840812102123p2144fb37hc9a0b2c958061c34@mail.gmail.com> Date: Thu, 11 Dec 2008 00:23:03 -0500 From: "Michael Proto" To: "Giorgos Keramidas" In-Reply-To: <87zlj390vw.fsf@kobe.laptop> MIME-Version: 1.0 References: <1de79840812092149t4d212027o2c908635419fa838@mail.gmail.com> <87zlj390vw.fsf@kobe.laptop> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: FreeBSD Current , freebsd-questions@freebsd.org Subject: Re: behavioral change of "read" builtin for sh on 8-CURRENT X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Dec 2008 05:23:06 -0000 Thanks! PR 129566 filed on this issue. -Proto On Wed, Dec 10, 2008 at 4:27 PM, Giorgos Keramidas wrote: > Hi Michael, > > This looks like a bug in 8.0-CURRENT. > > Can you please file a bug report and include the text you sent below? > > On Wed, 10 Dec 2008 00:49:58 -0500, "Michael Proto" > wrote: > > I've noticed a behavioral difference of the "read" builtin statement > within > > /bin/sh on CURRENT and I'm hoping someone can point me in the right > > direction on how to restore the old behavior. > > > > I have a /bin/sh script that accepts input for IP address information: > > > > #!/bin/sh > > set -x > > DEFINT=vr0 > > DEFIP=192.168.0.1 > > DEFMASK=255.255.255.0 > > read -p "Enter network interface [$DEFINT]: " -t 5 INT > > read -p "Enter IP address [$DEFIP]: " -t 5 IP > > read -p "Enter netmask [$DEFMASK]: " -t 5 MASK > > echo ${INT:=$DEFINT} : ${IP:=$DEFIP}/${MASK:=$DEFMASK} > > > > This script waits for terminal input for each of the above variables > (INT, > > IP, MASK) and defaults to a script-provided value if no input is entered > in > > 5 seconds for each variable. On 6.x and 7.x if I simply hit Enter at the > > prompt (and don't provide any input) no value is assigned to the variable > so > > my INT, IP, and MASK variables are set to null and the parameter > > substitution of the DEF* variables works as expected. > > > > On 8-CURRENT if I hit Enter with no input at the prompt the system seems > to > > recognize the newline as input and continues to sit there until I hit > Enter > > again. When I do this there appears to be a strange unprintable value > > assigned to the INT, IP, and MASK variables yet the variable subsitution > > doesn't work correctly. > > > > The man page on sh lists the following behavior for read: > > > > read [-p prompt] [-t timeout] [-er] variable ... > > The prompt is printed if the -p option is specified and the > > stan- > > dard input is a terminal. Then a line is read from the > > standard > > input. The trailing newline is deleted from the line and > the > > line is split as described in the section on White Space > > Splitting (Field Splitting) above, and the pieces are > assigned > > to > > the variables in order. If there are more pieces than > > variables, > > the remaining pieces (along with the characters in IFS that > > sepa- > > rated them) are assigned to the last variable. If there are > > more > > variables than pieces, the remaining variables are assigned > the > > null string. > > > > > > As I interpret this, read should delete the trailing newline and assign a > > null value since there is is no "input" before the newline. Then the > > variable substitution should take over and assign the DEF* variables > > appropriately. 6 and 7 follow this but 8 does not. > > > > Here's the output of the script (with set -x) to help show what I'm > seeing. > > > > This is on 6 and 7: > > > > + DEFINT=vr0 > > + DEFIP=192.168.0.1 > > + DEFMASK=255.255.255.0 > > + read -p Enter network interface [vr0]: -t 5 INT > > Enter network interface [vr0]: > > + read -p Enter IP address [192.168.0.1]: -t 5 IP > > Enter IP address [192.168.0.1]: > > + read -p Enter netmask [255.255.255.0]: -t 5 MASK > > Enter netmask [255.255.255.0]: > > + echo vr0 : 192.168.0.1/255.255.255.0 > > vr0 : 192.168.0.1/255.255.255.0 > > > > > > And this is what I see with 8: > > > > + DEFINT=vr0 > > + DEFIP=192.168.0.1 > > + DEFMASK=255.255.255.0 > > + read -p Enter network interface [vr0]: -t 5 INT > > Enter network interface [vr0]: > > + read -p Enter IP address [192.168.0.1]: -t 5 IP > > Enter IP address [192.168.0.1]: > > + read -p Enter netmask [255.255.255.0]: -t 5 MASK > > Enter netmask [255.255.255.0]: > > /: cho > > /: > > > > Strange that the "echo" statement is missing the first "e" character in > the > > debug output. > > > > Even stranger on 8-CURRENT, if I *do* enter input before the newline (say > I > > change the IP address or the network interface), the first character is > not > > echoed back to the screen but is still saved to the variable. Here's an > > example when I run the script and provide input at each prompt: > > > > + DEFINT=vr0 > > + DEFIP=192.168.0.1 > > + DEFMASK=255.255.255.0 > > + read -p Enter network interface [vr0]: -t 5 INT > > Enter network interface [vr0]: r0 > > + read -p Enter IP address [192.168.0.1]: -t 5 IP > > Enter IP address [192.168.0.1]: 92.168.0.1 > > + read -p Enter netmask [255.255.255.0]: -t 5 MASK > > Enter netmask [255.255.255.0]: 55.255.255.0 > > + echo br0 : 192.168.0.1/255.255.255.0 > > br0 : 192.168.0.1/255.255.255.0 > > + echo ifconfig br0 inet 192.168.0.1 netmask 255.255.255.0 > > > > Notice that when I'm prompted, the first character doesn't echo but is > still > > saved in the variable. > > > > > > Does anyone else see this same behavior? Any ideas on how to reset it > back > > to how it works in STABLE? I'm not doing anything special with IFS so I'm > > stumped on how to troubleshoot this. > > > > > > > > Thanks, > > Proto > > _______________________________________________ > > freebsd-questions@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" > > > > -- >