Re: bourne sh, problems with var setting in case/esac

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Article #1862

#1862

From: Andy Crump
Date: Thu, 29 Nov 1990 16:02

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>>>>> On 15 Nov 90 19:05:53 GMT, rdavis@connie.UUCP (Ray Davis) said:

Ray> In <1990Nov15.155604.16714@usenet.ins.cwru.edu> news@usenet.ins.cwru.edu writes:

>>if i don't pipe esac and not use cat, all is ok, but i want to pipe !

>Sh runs control structures with pipes in a subshell.  Variables set in a
>subshell cannot affect the parent's settings.

Ray> It isn't the control structure that is the problem, it's the
Ray> pipe.  Note that in ksh (and maybe SVR? sh), the pipe causes a
Ray> subshell, but redirecting the output of the case to a file does
Ray> not.  Note also that if you 'cat | case', the case is not in a
Ray> subshell.

I tried this on Intel SVR4 version 2.0 with both ksh and sh and they
behave exactly as everyone describes.  The pipe causes a subshell.
You have been zapped by Mr. SubShell.
--

    -- Andy Crump

    ...!tektronix!reed!littlei!andyc | andyc@littlei.intel.com
    ...!uunet!littlei!andyc          | andyc@littlei.uu.net

Disclaimer: Any opinions expressed here are my own and 
            not representive of Intel Corportation.

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References: <1236@netmuc.UUCP> <1990Nov15.155604.16714@usenet.ins.cwru.edu> <rdavis.658695953@connie.convex.com>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!ogicse!littlei!gandalf!andyc
From: andyc@bucky.intel.com (Andy Crump)
Newsgroups: comp.unix.shell
Subject: Re: bourne sh, problems with var setting in case/esac
Message-ID: <ANDYC.90Nov29160234@bucky.intel.com>
Date: 29 Nov 90 16:02:34 GMT
References: <1236@netmuc.UUCP> <1990Nov15.155604.16714@usenet.ins.cwru.edu>
 <rdavis.658695953@connie.convex.com>
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Distribution: comp
Organization: Intel Corporation, Hillsboro, Oregon
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In-reply-to: rdavis@connie.UUCP's message of 15 Nov 90 19:05:53 GMT

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