From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 712 invoked from network); 21 Aug 2001 14:22:58 -0000 Received: from sunsite.dk (130.225.51.30) by ns1.primenet.com.au with SMTP; 21 Aug 2001 14:22:58 -0000 Received: (qmail 19680 invoked by alias); 21 Aug 2001 14:22:34 -0000 Mailing-List: contact zsh-users-help@sunsite.dk; run by ezmlm Precedence: bulk X-No-Archive: yes X-Seq: 4158 Received: (qmail 19665 invoked from network); 21 Aug 2001 14:22:32 -0000 Recieved: from Richard.Curnow@st.com by popov with local (Exim 3.03 #5) id 15ZCPi-0006En-00; Tue, 21 Aug 2001 15:21:54 +0100 Date: Tue, 21 Aug 2001 15:21:54 +0100 From: Richard Curnow To: zsh-users@sunsite.auc.dk Subject: Re: Zsh Guide chapter 5 (substitutions) Message-ID: <20010821152154.A8668@popov.bri.st.com> Mail-Followup-To: zsh-users@sunsite.auc.dk References: <20010815230024.3E7F614284@pwstephenson.fsnet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.4i-nntp In-Reply-To: <20010815230024.3E7F614284@pwstephenson.fsnet.co.uk>; from pws@pwstephenson.fsnet.co.uk on Thu, Aug 16, 2001 at 12:00:18AM +0100 On page 74, 2nd para from the end, It seems a bit odd to signal a process to restart; why can't the operating system just restart it when you ask? The real answer is probably that signals provide an easy way for you to talk to the operating system without grovelling around in the dirt too much. I think it's to provide a way for a process to save and restore state across the suspension, by installing handlers for SIGTSTP and SIGCONT. I can think of a few cases I've come across where this applies : - if the process has done anything horrible to its /dev/tty, (e.g. echo off, changed the per-line/per-char input (ICANON?) mode, made stdin use asynchronous I/O etc), which would leave an unusable environment for the user back at the shell prompt. - some tools (verilog simulators etc) that use floating licenses seem to relinquish licenses when suspended and re-acquire them when restarted. Very nice of them! On Thu, Aug 16, 2001 at 12:00:18AM +0100, pws@pwstephenson.fsnet.co.uk wrote: > I've uploaded a new version of A User's Guide to the Z-Shell which you > can find at > http://sunsite.dk/zsh/Guide/ > > The main addition is chapter 5, which talks about all forms of shell > substitutions and expansions. Chapter 3 has been slightly edited. I'd > be interested in any comments on either, of course. It's possible -- Richard Curnow---by day : SuperH Core Architecture at STMicroelectronics curnowr@bristol.st.com---------www.superh.com-------------www.st.com---- and by night >>---richard.curnow@go.to---http://go.to/richard.curnow/---