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Re: Quit versus Clear["Global`*"]

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  • Subject: [mg121273] Re: Quit versus Clear["Global`*"]
  • From: DrMajorBob <btreat1 at>
  • Date: Wed, 7 Sep 2011 05:38:47 -0400 (EDT)
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  • References: <j3t5ga$58h$> <j3vc1k$ejo$>
  • Reply-to: drmajorbob at

When in doubt, Quit

Amen. Other remedies are always a kludge.


On Tue, 06 Sep 2011 02:57:01 -0500, tenons at <tenons at>  

> On Sep 4, 4:14 am, David Bailey <d... at> wrote:
>> On 03/09/2011 13:10, Themis Matsoukas wrote:> What is the difference  
>> between quitting the kernel and executing Clear["Global`*"]?
>> > Is there a command to quit the kernel, instead of selecting  
>> Quit/Local from there Evaluate menu?
>> > Thanks
>> Quit[] will quit the kernel.
>> Obviously Clear["Global`*"] would not clear information that might end
>> up in other contexts, whereas Quit[] will clear everything.
>> I never clear the global context - I just quit the kernel one way or
>> another. Restarting the kernel used to be rather slow, but with the
>> speed of a modern PC, there really doesn't seem much point doing
>> anything else unless you specifically wish to preserve some information
>> that is not in Global`.
>> I tend to quit the kernel quite a lot - e.g. between successive runs of
>> a program - why risk the confusion that can arise when two function
>> definitions end up coexisting!
>> David Bailey
> I agree whole-heartedly with this post.  I've found it the only way
> to stay out of trouble.
> I have a related problem that I hope I can get some suggestions for.
> GIF.exe has a memory leak (reported previously, acknowledged and is on
> someone's todo list at Wolfram, hopefully) which makes a certain set
> evaluations (which use ExportString[#,"GIF"]& extensively) unstable.
> (i.e., MathKernel crashes randomly and unceremoniously, or worse).
> What I would like to do is divide the set of evaluations into
> segments, run them successively quitting the MathKernel after each,
> and then restarting on the next segment.  The Quit[] clears out the
> buildup in GIF.exe. Obviously I can do this by babysitting and
> restarting each segment by hand (which I do, at approximately 15
> minute intervals, painfully wasting time).
> [I've tried many things including Uninstall["path/GIF.exe"] 'ing
> periodically and escaping to the shell to kill the process.  Neither
> improves stability. ]
> How can I carry this out automatically?

DrMajorBob at

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