Date: Mon, 20 Jul 2009 13:56:11 -0400 From: Lowell Gilbert <freebsd-stable-local@be-well.ilk.org> To: Glen Barber <glen.j.barber@gmail.com> Cc: stable@freebsd.org, Lowell Gilbert <freebsd-stable-local@be-well.ilk.org> Subject: Re: Shell execution ( [was] Re: Value of $? lost in the beginning of a function.) Message-ID: <44k523fdc4.fsf@be-well.ilk.org> In-Reply-To: <4ad871310907200702q6d13a44bqaeb2242d65866b16@mail.gmail.com> (Glen Barber's message of "Mon\, 20 Jul 2009 10\:02\:23 -0400") References: <4ad871310907191717g1ed90be7y92250f2addc38d43@mail.gmail.com> <44tz17k46h.fsf@lowell-desk.lan> <4ad871310907200702q6d13a44bqaeb2242d65866b16@mail.gmail.com>
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Glen Barber <glen.j.barber@gmail.com> writes: > Hi, Lowell > > On Mon, Jul 20, 2009 at 7:02 AM, Lowell > Gilbert<freebsd-stable-local@be-well.ilk.org> wrote: >> Glen Barber <glen.j.barber@gmail.com> writes: >> >>> Possibly off-topic... >>> >>> >>> 2009/7/19 Glen Barber <glen.j.barber@gmail.com>: >>>> 2009/7/19 Romain Tarti=E8re <romain@blogreen.org>: >>>>> Hi Glen, >>>>> >>>>> On Sun, Jul 19, 2009 at 04:32:28PM -0400, Glen Barber wrote: >>>>>> > % sh foo.sh >>>>>> > % zsh foo.sh >>>>>> > % bash foo.sh >>>>>> What happens if you replace '#!/bin/sh' with '#!/usr/local/bin/zsh' ? >>>>> >>>>> This is not related to my problem since I am not running the script >>>>> using ./foo.sh but directly using the proper shell. =A0sh just behaves >>>>> differently, that looks odd so I would like to know if it is a bug in= sh >>>>> or if there is no specification for this and the behaviour depends of >>>>> the implementation of each shell, in which case I have to tweak the >>>>> script I am porting to avoid this construct (passing $? as an argument >>>>> for example). >>>>> >>>>> Romain >>>>> >>>> >>>> My understanding was this: >>>> >>>> If you specify 'sh foo.sh' at the shell, the script will be run in a >>>> /bin/sh shell, _unless_ you override the shell _in_ the script. >>>> >>>> Ie, 'sh foo.sh' containing '#!/bin/sh' being redundant, but 'zsh >>>> foo.sh' containing '#!/bin/sh' would execute using zsh. >>>> >>>> >>> >>> I meant to say in the last line: "'#!/bin/sh' would override the 'zsh' = shell." >>> >>> Can someone enlighten me if I am wrong about this? >> >> The person to whom you were responding had it closer. >> >> The shell specified in the "#!" first line is only consulted if you run >> it as "./foo.sh". =A0Otherwise, it's input to the shell that you started, >> and the line is only a comment. >> > > I suppose that makes sense, but what if the script location is in the > user's $PATH? That would be the same as "./foo.sh".=20=20 The distinction is between whether the file is treated as an executable or as input to a script. You might find the manual page for execve(2) useful for more detail on how the former case is handled.
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