Re: [Help-bash] backgrounding a process sends it into a tailspin

[Cook, Rich]

On Sep 12, 2012, at 7:17 PM, Chet Ramey wrote:

> On 9/7/12 8:46 PM, Cook, Rich wrote:
>> Hello, 
>> I have built and installed gnuplot and wrapped it in a bash script.  The 
>> script simply makes a usage entry in a database, calls gnuplot, then notes 
>> that it exits.  I'm including the script below.  
>> 
>> When the user runs this script and puts it into the background, gnuplot 
>> immediately starts taking up 100% of a CPU, spinning in readline.  This only 
>> happens when gnuplot is wrapped in this way, not when it's called directly.  
>> I would like to avoid this behavior, obviously, but I would also like to 
>> continue using a wrapper script.  What is it about being called from a 
>> script that is causing this odd behavior on gnuplot's part?  
> 
> I can't reproduce this on Mac OS X, using bash-3.2 to bash-4.2 and
> gnuplot-4.whatever-fink-gives-you, or on Fedora 15, using bash-4.2 and
> gnuplot-4.4.  I used the orignal script without the imgtrack stuff.
> It doesn't matter whether I start the script in the background using `&'
> or in the foreground and use ^Z.  Even ^Z/bg doesn't cause any weird
> behavior.
> 
> Maybe we could get back to basics: system type, OS version, bash version,
> gnuplot version.

OK, sure, great, thanks
Here is some info: 
address@hidden (lclocal.el6): uname -a
Linux rzgpu2 2.6.32-220.23.1.1chaos.ch5.x86_64 #1 SMP Tue Jun 19 17:16:17 PDT 
2012 x86_64 x86_64 x86_64 GNU/Linux

chaos5 == rhel6 with some kernel mods, surely no changes to bash

address@hidden (lclocal.el6): bash --version
GNU bash, version 4.1.2(1)-release (x86_64-redhat-linux-gnu)

address@hidden (lclocal.el6): gnuplot --version
gnuplot 4.4 patchlevel 3

Also happens on gnuplot 4.6.0


> Chet
> 
> -- 
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
>                ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, ITS, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/

-- 
✐Richard Cook   
✇ Lawrence Livermore National Laboratory
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---
Information Management & Graphics Grp., Services & Development Div., Integrated 
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(opinions expressed herein are mine and not those of LLNL)