Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com Message-ID: <3E550957.1070306@veritas.com> Date: Thu, 20 Feb 2003 08:59:03 -0800 From: Bob McGowan Organization: VERITAS Software, Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021130 X-Accept-Language: en-us, en MIME-Version: 1.0 To: cygwin@cygwin.com CC: Fred Ma Subject: Re: Question re. export environment variable References: <3E550005.84B691EA@doe.carleton.ca> In-Reply-To: <3E550005.84B691EA@doe.carleton.ca> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Fred, perhaps this will help: echo $TEST # Test has no value, hence the blank line. $ TEST=noexport # Set but not exported $ echo $TEST noexport $ env|grep TEST # Nothing found, no output. $ export TEST # Export it. $ env|grep TEST # And now it's found in the environment. TEST=noexport $ TEST=second # Change its value. $ env|grep TEST # Same search as above, but the value is changed. TEST=second Perhaps the easiest way to look at it is to think of exporting as making a type of global variable. Everyone (within certain limits; for the shell, only its children...) will see the exported variable. If the value changes, it changes "everywhere". I've quoted everywhere because this only applies to children invoked after the change. So if TEST=second and you run an xterm, the new shell sees TEST=second. Change TEST=third in the first shell, you still have TEST=second in the second shell, since it already got its value for TEST. Start a third shell from the first, it will see TEST=third. And so on. Fred Ma wrote: > Hello, > > I'm using cygwin bash 2.05b-8 (it's actually gnu). > I thought that $HOSTNAME was an environment > variable. When I run gnu make (I'm pretty > sure this is not a make problem), $(HOSTNAME) > is empty. It gets fixed if I do "export HOSTNAME" > before running make. > > Is there a way to check if the export command > has been applied to $HOSTNAME? Does the > actual transcription of $HOSTNAME's value to > the environment happen only once, when > "export" is applied, or is there a continual > monitoring an mirroring of changes to $HOSTNAME > forever after applying "export"? > > Fred > > > > -- > Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple > Bug reporting: http://cygwin.com/bugs.html > Documentation: http://cygwin.com/docs.html > FAQ: http://cygwin.com/faq/ -- Bob McGowan Staff Development Engineer VERITAS Software rmcgowan@veritas.com -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Bug reporting: http://cygwin.com/bugs.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/